healthcare waste dissertation

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Open Access

Peer-reviewed

Research Article

Assessment of healthcare waste management practices and associated factors in Addis Ababa City Administration Public Health Facilities

Roles Writing – original draft, Writing – review & editing

Affiliation Menelik II Medical and Health Science College, Addis Ababa, Ethiopia

Roles Methodology, Writing – review & editing

* E-mail: [email protected]

Affiliation University of South Africa, Pretoria, South Africa

• Menelik Legesse Tadesse, 
• Bethabile Lovely Dolamo

• Published: November 4, 2022
• https://doi.org/10.1371/journal.pone.0277209
• Peer Review
• Reader Comments

Healthcare waste management is very important due to its hazardous nature that can cause risk to human health and the environment. In developing countries, healthcare waste has not received much attention and has been disposed of together with municipal waste. The aim of the study was to assess the healthcare waste management practices in Addis Ababa City Administration Public Health Facilities.

An institutional-based cross-sectional design was used for the study at Addis Ababa city 15 Public health centres and 3 hospitals. Data were collected using self-administered questionnaires distributed to 636 randomly selected healthcare waste handlers and managers. Observational check list also used. The data were entered into the EPI- INFO version TM 7 and exported to IBM SPSS 20 for analysis. Both descriptive and analytic statistics were employed.

Among the respondents, 358 (90.86%) from health centres and 96.38% (133) from hospitals indicated that their facilities had separate containers for hazardous and non-hazardous waste however, 61 (15.48%) from health centres and 29 (21.01%) from hospitals indicated that healthcare waste containers were not clearly marked or labelled. The study found that the main forms of on-site treatment of healthcare waste for health centres and hospitals before disposal were burning. Manager respondents from the health centres 65 (92.86%), 64 (91.43%) and from hospitals 31 (91.18%), 30 (88.24%) indicated that healthcare waste handlers were used protective clothing when handling waste and were provided with protective clothing when handling healthcare waste respectively.

In this study healthcare waste management among healthcare waste handlers and healthcare facility managers were not getting full attention. Collection of healthcare waste were not done regularly, containers were not clearly marked and were not located in appropriate areas where they might be needed. Support healthcare waste handlers by training help to improve their knowledge, attitude and practice.

Citation: Tadesse ML, Dolamo BL (2022) Assessment of healthcare waste management practices and associated factors in Addis Ababa City Administration Public Health Facilities. PLoS ONE 17(11): e0277209. https://doi.org/10.1371/journal.pone.0277209

Editor: Nor Adilla Rashidi, Universiti Teknologi Petronas: Universiti Teknologi PETRONAS, MALAYSIA

Received: December 23, 2021; Accepted: October 22, 2022; Published: November 4, 2022

Copyright: © 2022 Tadesse, Dolamo. This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: All manuscript files are available from the UNISA database URI: http://hdl.handle.net/10500/26614 .

Funding: The author(s) received no specific funding for this work.

Competing interests: The authors have declared that no competing interests exist.

Healthcare waste produced in the course of health care activities entails a higher risk of infection and injuries than municipal waste. In developing countries, healthcare waste has not received much attention and has been disposed of together with municipal waste [ 1 ]. In Ethiopia, improper healthcare waste management is alarming and poses a serious threat to public health [ 2 ].

The risk of healthcare waste and its management has become a global cause of concern. The majority of the problems are associated with an exponential growth in the health care sector together with low or non-compliance with guidelines and recommendations. The management of healthcare waste requires increased attention and diligence to avoid substantial disease burden associated with poor practice, including exposure to infectious agents and toxic substances [ 3 , 4 ]. According to the United Nations Environmental Program [ 5 ], healthcare waste is one of the most troublesome forms of waste and one of the most important environmental concerns for the global community. Healthcare waste production at hospitals and its management are important issues worldwide [ 6 ]. Since the mid-1990s the world has experienced a dramatic increase in the amount of hazardous waste generated, at the same time, a vigorous drive for sustainable development and increased environmental awareness and concern [ 7 ].

Poor waste management practices at the level of healthcare facilities, including failure to segregation of waste and errors in the colour coding of waste disposal, can result in hazardous waste being disposed of not only improperly, but also accessible to community members [ 8 ]. In Botswana, [ 9 ] found that due to a lack of understanding of the importance of colour coding and segregation in the management of healthcare waste, patients were given healthcare waste bags for their personal belongings and clothing after being discharged from the hospital. In Korea [ 10 ] found that policy on healthcare waste management was inadequate and required strengthening.

The poor management of healthcare waste (HCW) is associated with a lack of adequate training of healthcare workers and disposal practices, including disposal with municipal waste together with some autoclave treatment and incinerator use.

The studies conducted in Ethiopia health centres and hospitals focused on healthcare waste generation and did not consider its management and intervention [ 2 , 11 ]. The high generation of healthcare waste is due to the increasing population and the use of healthcare facilities that exceeds the ability of Addis Ababa City Administration to manage the increased amount of healthcare waste. This study wished to assess the management system The concern is about the lack of appropriate HCW segregation, selection, handling, storage, transport, treatment and final disposal. This motivated the researcher to conduct this study to assess the healthcare waste management in health facilities in Addis Ababa City Health Bureau. Between 2011 and 2016, the Addis Ababa City Administration Health Bureau built more than 60 health centres and one [ 1 ] referral hospital [ 12 ].

Materials and methods

Study setting and design.

The study setting was Addis Ababa, the capital city of Ethiopia. It is the largest and most populous city in the country [ 13 ]. The city has three layers of administration, the city administration at the top, 10 sub-cities administration in the middle and 116 Woredas (Districts) at the bottom [ 12 ]. There were 6 public referral hospitals and 95 functional public health centers during the study period. A facility based cross-sectional study was conducted among healthcare waste handlers and managers. The study assessed the healthcare waste management practices in 15 selected public health centres and 3 hospitals. Data was obtained from questionnaires distributed to 636 randomly selected healthcare professionals, ancillary staff and managers from January 24 to February 24, 2018.

Source population

All healthcare waste handlers and managers in Addis Ababa City Administration public health centres and hospitals.

Study population

Sampled healthcare waste handlers and managers from selected health centres and hospitals.

Inclusion and exclusion criteria

Healthcare waste handlers and managers (Doctors, Health Officers, Nurses, midwifes, pharmacists, laboratory technicians, Environmental health professionals, Biomedical engineers, ancillary staffs comprised cleaners, porters and operatives for handling waste selected by proportion.) in 15 health centres and 3 hospitals who were worked more than six months and agree to participate in the study were included. Healthcare waste handlers and managers who were absent at the time of data collection were excluded from the study.

Sample size and sampling techniques

The sample size determined for this study was determined by a single population proportion formula with the assumption of 50%, 95% confidence interval and 5% marginal error. The researcher used multistage sampling in this study and calculate the design effect of 2. Correction formula was also used because the number of healthcare workers were less than 10000. A total of 636 participants were selected out of which 532 were healthcare waste handlers and 104 were managers. Proportional allocation was performed 394 participant healthcare waste handlers were from 15 health centres and 138 were from 3 hospitals. Moreover 70 managers were from health centres and 34 were from hospitals. Simple random sampling method was used to select participants from both health centres and hospitals.

Data collection tool

Data was collected by means of questionnaires and observational check list. To reduce subjectivity (information bias), the principal investigator adopted a structured questionnaire from World Health Organization’s healthcare waste management rapid assessment tools [ 14 ] as a data collection tool in line with the research objective. The questionnaire included respondents’ demographic characteristics, knowledge and practice of HCW management. The questionnaire consisted of closed questions (requiring a ‘Yes’ or ‘No’ answer). The main questions covered segregation, collection, transportation, storage, treatment and disposal, waste recycling and re-use, occupational health and safety, internal policies, and administration and healthcare waste management. Data collectors distributed the questionnaires in the 15 health centres and 3 hospitals to the respondents. Observation was conducted by the data collectors and supervisors to see the waste management practice of healthcare waste handlers and the work site to health centres and hospitals. The data collectors used the prepared observational check list to follow the HCW management practice and captured supporting photographs.

Data quality control

Fifteen data collectors who graduated from a college with Grade 10+3 diploma in health science were used for data collection on healthcare waste management. Eight supervisors who were BSc graduates in Environmental Health or related fields assisted the principal investigator with the data collection. Training manual was prepared for two days of training. The principal investigator gave training to data collectors and supervisors, including data collection and fieldworkers practice in data collection and data-collection tools. Information sheet and consent form also attached with the data collection tool to share the information about the study. Data collection tools and observational check lists was pre-tested to two health centers and one hospital other than the study areas. Respondents who were not able to read, the English language questionnaires were the tool were translated to local language Amharic by professional translator and assisted by the data collectors. Daily onsite supervision was made by the supervisors and principal investigator during data collection assuring ethical issue and respondents assuring an animosity.

Data processing and analysis

Data was entered by EPI- INFO TM 7 after a manual check for completeness. The entered data were exported to IBM SPSS Version 20. Both descriptive and inferential statistics were used. Data analysis was performed separately for each of health centres and hospitals which were grouped by category. Tables and graphs were used to show frequencies, percentage, bivariate logistic regression analysis to identify candidate variables for multivariable logistic regression analysis. The multivariable analysis a significant association was found with a p-value of less than 0.05. the association were presented with an adjusted odds ratio (AOR) and corresponding 95% CI.

Ethical consideration

Ethical approval and clearance were obtained from the Higher Degrees Committee, Department of Health Studies, University of South Africa and Addis Ababa City Administration Health Bureau to conduct the study. The letter was submitted to both health centers and hospital administrators to begin the study. A written information sheet and consent form was provided to all participants. The participants were informed of the purpose of the study; that participation was voluntary, and that all information would be treated strictly confidentially. The participants signed informed consent and also informed to withdraw from the study at any time was clearly stated for the participants.

Sociodemographic characteristics of the respondents

A total of 636 healthcare waste handlers and managers, 370 (58.18%) and 266 (41.82%) were males and females participated respectively ( Table 1 ). In this study 15 health centres and 3 general hospitals were selected (Figs 1 and 2 ). The largest 251 (39%) participants were nurses 162 (64.5%) worked at health centres and 89 (35.5%) worked at hospitals, the least 2 (0.31%) participants were biomedical engineers worked at hospitals ( Fig 3 ).

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The respondents’ age ranged from 20 to 59 years. Of the respondents, 372 (58.49%) were aged between 20–29, 216 (33.96%) were aged between 30–39, and 5.03% (32) were aged between 40–49. The mean age of the respondents was 30.9 years ( Table 2 ).

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Of the respondents, 421 (66.19%), 158 (24.84%), 24 (3.77%) and 21 (3.3%) had work experience of, 1–5 years, 6–10 year, 11–15 years and 21 years and more experience respectively ( Table 3 ).

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Healthcare waste management practice

From this study healthcare waste handlers, 350 (88.83%) from health centres and 127 (92.03%) from hospitals indicated that the health facility they worked at had separate storage areas for HCW. With reference to storage, 358 (90.86%) from health centres and 133 (96.38%) from hospitals indicated that their facilities had separate containers for hazardous and non-hazardous waste. The respondent healthcare waste handlers, 61 (15.48%) from health centres and 29 (21.01%) from hospitals indicated that the healthcare waste containers were not clearly marked or labelled ( Table 4 ).

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Healthcare waste handlers, 339 (86.04%) from health centres and 106 (76.81%) from hospitals indicated that the HCW containers were located appropriate areas where they might be needed. Majority of respondent healthcare waste handlers, 325 (82.49%) and 83. 330 (76%) from health centres and 105 (76.09%) and 99 (71.74%) from hospitals indicated that the HCW containers in health facilities were made of leak-proof material and the HCW containers were easy to carry respectively ( Table 4 ).

Respondents from health centres343 (87.06%) and 119 (86.23%) from hospitals stated that the sharps containers were made of puncture-resistant material but 51 (12.94%) from health centres and 41 (22.71%) from hospitals indicated that sharps containers were not closed securely and disposed of whenever they were 3/4 full. Most of the respondents, 335 (85.02%) from health centres and 87 (63.04%) from hospitals stated that the HCW containers were emptied daily or whenever they were 3/4 full ( Table 4 ).

Healthcare waste handlers from health centres 96 (24.37%) and 41 (29.71%) from hospitals indicated that no formal or informal separation of waste took place at their health facilities. Respondents from health centres 209 (53.03%) and 87 (63.04%) from hospitals indicated that plastics and intravenous sets were not kept separately for recycling. Healthcare waste handlers, 126 (31.98%) and 310 (76.68%) from health centres and 49 (35.51%) and 93 (67.39%) from hospitals indicated that not all waste handlers wore heavy duty gloves and sturdy shoes when handling HCW and washed their hands and their hard duty gloves after handling waste respectively ( Table 4 ).

The respondent healthcare handlers 157 (39.85%), 260 (65.99%), 58.12% (229), 246 (62.44%) and 56 (14.21%) from health centres and 61 (44.2%), 97 (70.29%), 93 (67.39%), 90 (65.22%) and 38 (27.54%) from hospitals indicated cytotoxic, pathological, reagent, outdated pharmaceutical and radioactive waste was indicated their facility generated as waste of special concern ( Table 4 ).

None of the respondents who indicated that their facilities generated HCW of special concern indicated how the disposal thereof was handled. The respondents were asked to indicate how liquid waste was disposed of and to specify for cytotoxic and reagent processing liquids. Healthcare waste handlers, 20 (5.08%) from health centres and 10 (7.25%) from hospitals indicated that liquid waste was disposed of via sinks, and 23 (5.84%) from health centres and 4 (2.9%) from hospitals indicated via sewers. None of the respondents specified cytotoxic or reagent processing liquids ( Table 4 ).

Types of HCW generation

The types of HCW generated and observed in respective healthcare facilities in daily basis were asked to the study participants. Most respondents observed, 277 (70.30%), 261 (66.24%) and 265 (67.26%), 114 (82.61%) from health centres and hospitals indicated used gloves and sharps respectively were generated more in daily basis ( Table 5 ).

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The type of HCW least generated and observed from health centres and hospitals 80 (20.30%), 67 (48.55%) and 60 (15.23%), 59 (42.7%) were indicated human tissue and organ and excreta respectively ( Table 5 ).

The respondents were asked to indicate the on-site means of transportation observed of HCW in their healthcare facilities. The study found that health centres mainly used buckets followed by pedal bins and trolleys to transport HCW on site while hospitals used mainly pedal bins and sometimes buckets and trolleys ( Fig 4 ).

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Healthcare waste management and managers

Regarding HCW management issues, a total of 104 managers respondents, 70 from health centres and 34 from hospitals were participated. The type of professions to managers participated in the study were nurses, laboratory technicians and health officers accounted 37 (35.6%) and 15 (14.4%) each respectively ( Table 6 ).

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Manager respondents, 69 (98.57%) from health centres and 31 (91.18%) from hospitals indicated that HCW generated by their facilities was segregated. From health centres 47 (61.43%) and from hospitals 24 (70.59%) indicated that the HCW was securely stored before transportation to the incinerator. Healthcare manager from the health centres 65 (92.86%) and 31 (91.18%) from hospitals indicated that healthcare waste handlers used protective clothing when handling waste, and 64 (91.43%) from health centres and 30 (88.24%) from hospitals indicated that the waste handlers were provided with protective clothing when handling HCW ( Table 7 ).

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Managers from health centres 47(67.14%) and hospitals 21(61.76%) indicated that there were a current operational standard for HCW management in their health facilities. Forty-nine (70.0%) from health centres and 25(73.53%) from hospitals indicated they had applicable guideline for HCW in the health facilities, beside 57(81.43%) and 23(67.65%) from health centres and hospitals respectively indicated HCW management committee organized in healthcare facilities ( Table 7 ).

The respondent managers were asked to indicate the type of protective clothing used for handling HCW in health centres, 45 (64.29%) used gloves; 35 (50%) used gowns; 17 (24.29%) used aprons; 23 (32.86%) used sturdy shoes; 10 (14.29%) used goggles; 5 (7.14%) used capes, and 20 (28.57%) used masks. Of the respondents from hospitals, 21 (61.76%) used gloves; 9 (26.47%) used gowns; 11 (32.35%) used aprons; 9 (26.47%) used sturdy shoes; 12 (35.29%) used goggles; 3 (8.82%) used capes, and 8 (23.53%) used masks ( Table 8 ).

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The respondent managers were asked to rate their facilities’ handling and segregation of HCW in health centres, 37 (52.86%) rated the handling of HCW good; 20 (28.57%) rated it very good; 7 (10%) rated it excellent, and 6 (8.57%) rated it poor. The respondent managers in the hospitals, 16 (47.06%) rated the handling good; 13 (38.24%) very good; 5 (14.71%) poor, and none rated it excellent ( Fig 5A ).

Rate of handling (a) and segregation (b) of HCW in the study health facilities, Addis Ababa City Administration, February 2018.

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Respondent managers in health centres, 34 (48.57%) rated the segregation good; 23 (32.86%) very good; 8 (11.43%) poor, and 5 (7.14%) excellent. Manager respondents from hospitals, 18 (52.94%) rated the segregation good; 10 (29.41%) rated it very good; 5 (14.71%) rated it poor, and 1 (2.94%) rated it excellent ( Fig 5B ).

The manager respondents were asked to indicate the method and means of collection and off-site disposal of HCW, 14 (20%) from health centres and 7 (20.60%) from hospitals indicated that the municipality collected the HCW for off-site disposal. Of the respondents, 1 (1.43%) from the health centres and 1 (2.94%) from the hospitals indicated that a cooperative organisation was responsible for collection and off-site HCW disposal ( Table 9 ). Most of the respondents did not answer the question.

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The manager respondents were asked what was used to store hazardous HCW prior to disposal, from health centres, 34 (48.57%) indicated red plastic healthcare waste bags; 16 (22.86%) indicated yellow sharps containers; 11 (15.71%) indicated ‘other’ and specified large interim containers; 5 (7.14%) indicated black plastic refuse bags; 3 (4.29%) indicated pedal bins; 1 (1.43%) indicated standard metal dustbins. From hospitals, 58.82% [ 20 ] indicated red plastic healthcare waste bags; 6 (17.65%) yellow sharps containers; 4 (11.76%) pedal bins; 2 (5.88%) black plastic refuse bags; 1 (2.94%) indicated standard metal dustbins, and 1 (2.94%) indicated ‘other’ and specified large interim containers ( Fig 6 ).

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The respondent managers were asked how HCW was transported on-site for storage before collection for off-site disposal, from health centres, 24 (34.29%) indicated in pedal bins; 40 (57.14%) indicated buckets, and 6 (8.57%) indicated trolleys. Respondent managers from hospitals, 28 (82.35%) indicated pedal bins; 3 (8.82%) indicated buckets, and 3 (8.82%) indicated trolleys ( Table 11 ).

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Managers were asked who was responsible for HCW management in their facilities, in health centres, 28 (40%) indicated sanitarian/environmental health professionals were responsible for HCW management; 27 (38.57%) indicated safety officers, and 15 (21.43%) indicated ‘other’ and specified (laboratory technicians, midwifes, ancillary staffs) ( Fig 7 ).

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Managers from hospitals, 28 (82.35%) indicated sanitarian/environmental health professionals were responsible for HCW management; 5 (14.71%) indicated safety officers, and 1 (2.94%) indicated ‘other’ and specified ancillary staff ( Fig 7 ).

Risks of the current waste management system

The respondent managers were asked to indicate whether their health facilities had concerns about HCW management, 64 (91.43%) from health centres and 30 (88.24%) from hospitals indicated that management had concerns about HCW management. Managers from health centres 35 (50.0%) and from hospitals 21 (61.76%) indicated that the HCW posed risks to waste collectors; 19 (27.14%) from health centres and 24 (70.59%) from hospitals indicated that waste collectors (handlers) had been injured by needles. Respondent managers, 40 (57.14%) from health centres and 24 (70.59%) from the hospitals indicated that their facilities had a register for injury or HCW contamination to staff ( Table 12 ).

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The respondent managers were asked to indicate the number of HCW handlers (ancillary/janitors) working at their facilities, from health centres, 59 (84.29%) indicated 5 or more; 3 (4.29%) indicated 4; 5 (7.14%) indicated 3, and1 (1.43%) indicated 1. Manager respondents from hospitals, 29 (85.29%) indicated 5 or more; 3 (8.82%) indicated 2, and 2 (5.88%) indicated 1 ( Fig 8 ).

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The Manager respondents were asked to indicate the type of injuries sustained in their health facilities in the previous 12 months, from health centres, 8 (11.43%) indicated deep injuries; 10 (14.29%) indicated slight skin penetration; 5 (7.14%) indicated superficial, and 7 (10%) indicated splash injuries. From hospital managers, 12 (35.29%) indicated deep injuries; 15 (44.12%) indicated slight skin penetration; 14 (41.18%) indicated superficial, and 13 (38.24%) indicated splash injuries ( Table 13 ).

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Observation

The tide line of waste management with reference to waste minimisation, segregation, storage, handling, collection, and treatment was not properly and adequately practised by any of the surveyed health centres and hospitals. During the study 15 health centres and 3 hospitals selected were observed.

Interim storage

Of the health care facilities, 13 health centres and 1 hospital had interim storage sites and HCW disposal sites located in areas minimally accessible to their staff. Six health centres and 2 hospitals had interim storage containers that had no lids to prevent odour and escape of wastes and waste leakage. Open plastic buckets and safety boxes were used to transport waste manually to the disposal site. In 10 health centres and the 3 hospitals HCW stored on site remained on site for more than 48 hours before final disposal ( Table 14 ).

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Treatment and disposal of HCW

During the study period, almost all the health centres and hospitals did no use disinfection of HCW storage/collection utilities treatment (used chemical treatment or autoclaving) for HCW before disposal for on-site and off-site. Almost all the health centres and hospitals disposed of all HCW inside their compounds (on-site) as incineration considered the final treatment except placenta and surgically removed body parts. During observation, 1 health centre and 3 hospitals disposed of the HCW outside the compound (off-site) ( Table 15 ). The disposals of ash residues were seen to the field near by the incinerator during observation ( Fig 9 ). The burial site for placenta and surgical removals and were away from any water source at most of the health centres and hospitals. All the health facilities except 1 health centre had incinerators on the premises. In 3 of the health facilities, the incinerators were located downwind from the main service area. The incinerators of 11 health centres and 2 hospitals had sufficient air inlets on the side. At 12 of the health centres and all the 3 hospitals ash residues from the incinerators was disposed of inside the compound. The incinerators at 8 of the health centres and 2 of the hospitals were not surrounded by a fence or wall to limit access to scavengers ( Fig 10A and 10B ). Burial pits such as placenta pits and surgical removal pits were employed for final on-site waste disposal. The burial pits in most of the health centres and hospitals was 1–2 meters wide and 2–5 meters deep and the bottom of the pit was at least 1.8 meters above the water table ( Table 15 ).

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Incinerator (a) and placenta pit (b) with no fencing in one of the study health centres, Addis Ababa City Administration, February 2018.

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During observation all healthcare facilities used incineration for on-site HCW disposal except 1 health centre. The health centre that did not incinerate HCW disposed of it by open burning in the premises ( Table 16 ). All hospitals used municipality for off- site disposal moreover incineration for disposal of HCW. Most, 12 health centres had no off-site disposal for HCW some 3 of the health centres used cooperative organization for HCW off-site disposal beside incineration ( Table 16 ).

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Factors associated with healthcare waste handling practice

In the bivariate logistic regression analysis; Sex, age group, occupational category, work experience, type of health facility, separate container for HCW, located in appropriate place, leak proof materials used for HCW collection, labelling or marking of HCW container, easy to carry by the handlers, puncture- resistant material for sharps, HCW containers emptied daily or whenever ¾ full, formal or informal separation of HCW takes place, recycling of used plastic materials, HCW handlers wear heavy duty gloves and sturdy shoes, wash both hard heavy duty gloves and hands after handling HCW, means of transportation for HCW and generation of HCW of special concern (cytotoxic) showed statistically significant association with separate storage area for healthcare waste ( Table 17 ).

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The backward stepwise multivariate logistic regression analysis has shown that the odds of healthcare waste handling practice was found to increase by 5 times among using puncture resistant material for sharps [AOR = 4.82, 95% CI: (2.32, 10.02)]. The generation of cytotoxic waste had an association with the healthcare waste handling practice. Generation of cytotoxic waste [AOR = 8.37, 95% CI: (3.20, 21.88)] were 8.37 times more likely to health care waste handling practice ( Table 17 ).

From previous study done in Addis Ababa half of the health centers didn’t have separate containers for the collection of hazardous and non-hazardous wastes moreover the labeling of the waste containers didn’t see by seven of the study health centers [ 2 ]. In this study most respondents, 358 (90.86%) from the health centres and 133 (96.38%) from the hospitals indicated that their facilities had separate containers for hazardous and non-hazardous waste also some respondents 15.48% (61) from the health centres and 29 (21.01%) from the hospitals indicated that the healthcare waste containers were not clearly marked or labelled. Two hundred and forty-one, (67.3%) used the readily existing waste bins for placing of medical waste in South Omo Zone public health facilities [ 15 ]. The difference might be in organizing different management structure in the health care facilities.

In this study collection of HCW in the healthcare facilities was not regularly done, 55 (13.96%) from the health centres and 32 (23.19%) from the hospitals indicated that the HCW containers were not located in appropriate areas where they might be needed. The study from three hospitals of Addis Ababa indicated, HCW materials were collected daily basis while the collection program was irregular in the most hospitals [ 11 ]. The reason might be either there is a shortage of containers or negligence by the coordinators.

HCW containers in the health facilities were not made of leak-proof material it was indicated by the respondents, 69 (17.51%) from the health centres and 33 (24.26%) from the hospitals. It is also similar to the study done in Addis Ababa most of the HCW at the hospitals was found to be collected in perforated plastic bins that are intended for use in administrative areas only [ 11 ].

The study found that HCW containers were not easy to carry for transportation in the healthcare facilities, it was indicated by the respondents, 64 (16.24%) from the health centres and 39 (28.26%) from the hospitals. Most health centres mainly used buckets followed by pedal bins and trolleys to transport HCW on site while the hospitals used mainly pedal bins and sometimes buckets and trolleys. The study conducted in Addis Ababa private clinics showed 16 (5.8%) of the clinics had trolley/wheelbarrow and 2 (0.7%) of the clinics were linked with the sewerage lines [ 16 ]. The overall waste transporting practice was poor in 238 (85.6%) of the clinics [ 16 ]. The similarity might be the healthcare facilities consider to transporting HCW be the lower priority to manage.

In this study 310(76.65%) from health centres and 93(67.39%) from hospitals indicated that healthcare waste handlers washed their hands after handling wastes. Study done in Addis Ababa government hospitals, 57.6% professionals followed standard precaution practice after any direct contact to patients and their disposals [ 17 ]. This indicates most of the workers has a good practice to standard precaution practices.

Off-site disposal of HCW implemented in the healthcare facilities was assured by the respondents, 14 (20%) from the health centres and 7 (20.60%) from the hospitals and most of them indicated that the municipality collected the HCW for off-site disposal. Similarly, the study conducted in Addis Ababa hospitals showed that dispose their waste at off-site, the untreated hospital waste materials in the central storage area were finally loaded onto vehicles and transported to “koshe” unsanitary landfill site for open dumping [ 11 ]. This might be the healthcare facilities has a problem to treatment or disinfection of HCW which pose infection to human and the environment.

In this study application of operational standards and guidelines for HCW management in the healthcare facilities also limited, it was indicated by respondent managers from the health centres, 23 (32.86%) and from hospital 13 (38.23%) indicated there was no current operational standard for HCW management. In previous study conducted in Addis Ababa six out of ten studied health centers, Standard Operational Procedures, as well as any applicable local or regional guidelines about healthcare waste management were not found [ 2 ]. But another study done in Bahir Dar private and public hospitals 161(83.9%) and 179(79.2%) respectively indicated healthcare workers responded as there were rules and regulations regarding HCW management in the health facilities [ 18 ] also study done in South Omo Zone public health facilities indicated 41.3% of respondents apply medical waste management guidelines and policy to manage health-care waste correctly [ 15 ]. The reason might be either preparation of HCW management guideline by health facilities or the policy makers do consider HCW as an issue of priority.

In this study indicated most healthcare facilities had no HCW management committees 13 (18.57%) and 11 (32.35%) from the health centres and hospitals respectively also study done in Bahir Dar 59(30.7%) of private hospitals and 86(38.1%) of public hospitals health care workers indicated had no healthcare waste management committee in the health facilities [ 18 ].

Incineration was the most common method of treatment for HCW in studied healthcare facilities in Addis Ababa. Similar studies in Belo Horizonte, Brazil showed 60% of HCW treatment technology goes directly to incineration [ 19 ]. There is no centralized incineration for all HCFs in Addis Ababa and surrounding regions to destroy pharmaceutical wastes. Most of the study HCFs had incinerators on the premises; only a few incinerators were located downwind from the main service area burn all hazardous and non-hazardous waste together. Most incinerators had sufficient air inlets on the side in most cases ash from the incinerators was disposed of inside the compound. Many of the incinerators were not surrounded by a fence or wall to limit access to scavengers. The finding in line with other hospitals and private clinics study in Addis Ababa showed the main HCW disposal mechanism was incineration, incinerators incinerating all the solid HCWs together and used low combustion, single chamber, brick incinerators, and barrels in clinics incinerator as a treatment/final waste disposal method [ 11 , 16 ]. A systematic review done in Ethiopia waste treatment and disposal practice indicated low combustion incinerator was used to treat all the HCW types [ 20 ]. This might be due to lack of proper way of quantifying the types of waste management utility supply, poor financial allocation and rules and regulations.

Healthcare waste management system had been given very little attention in all health centers and hospitals. Pretreatment of infectious solid waste and liquid waste must be practiced before disposing helps to minimize the transmission of most pathogens to human and environment. Intervention measures are important point to fill the gap in knowledge, practice and attitude should be supported by training on healthcare waste management for waste handlers and managers bring greatest change on practice and management of HCWs. Healthcare facilities collaborate with private and non-government organization as partners or other stake holders also important strengthening Public Private Partnership is very important. The presence of applicable national, regional and local guidelines for HCW management practice is helpful for all healthcare facilities to guide all aspects in HCW management. The findings of the study should contribute to the achievement of the United Nations [ 21 ] sustainable development goals (SDGs) for 2016–2030, which are aimed at bringing about a sustainable world and protecting the planet.

Limitation of the study

This study has the following limitation: the study conducted was cross-sectional and couldn’t identify causality. The study was conducted in public healthcare facilities healthcare waste handlers and managers and couldn’t represent healthcare waste handlers and managers outside the public healthcare facilities (private HCF). The study is conducted on healthcare waste management issues other studies should also be conducted the generation rate is very important.

Acknowledgments

First, I would like to express my deepest gratitude to Professor Bethabile Lovely Dolamo for her unreserved support throughout the study period. I sincerely thank University of South Africa, Kotebe Education University Menelik II Medical and Health Science College, Addis Ababa City Government Health Bureau, head of the study health centers and hospital case teams and managers for their unreserved cooperation during data collection time. My deepest gratitude also goes to all data collectors and supervisor for their commitment during data collection. I would like to thank my beloved wife Alemnesh Mude, daughters Bezawit Menelik and Hermela Menelik for their patience during the study period.

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Townend, William King. "Assessment and delivery of sustainable healthcare wastes management." Thesis, Imperial College London, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.429172.

Ramabitsa-Siimane, Ts'aletseng. "The identification of environmentally sound technologies for healthcare waste management in Lesotho." Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-05112006-114349.

Gomes, Keila Adiene Guimarães. "Caracterização dos resíduos sólidos de serviços de saúde do Hospital Escola Hélvio Auto em Maceió AL, visando a elaboração e implantação do plano de gerenciamento de resíduos." Universidade Federal de Alagoas, 2011. http://repositorio.ufal.br/handle/riufal/423.

Pugliesi, Érica. "Estudo da evolução da composição dos resíduos de serviços de saúde (RSS) e dos procedimentos adotados para o seu gerenciamento integrado, no Hospital Irmandade Santa Casa de Misericórdia de São Carlos - SP." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/18/18139/tde-18112011-160242/.

Ciplak, Nesli. "Healthcare waste management in Istanbul : improving decision making." Thesis, University of Leeds, 2012. http://etheses.whiterose.ac.uk/15229/.

Domingo, Nikula. "Reducing construction waste in healthcare projects : a project lifecycle approach." Thesis, Loughborough University, 2011. https://dspace.lboro.ac.uk/2134/9107.

Fernand, Rosemary A. "The fate and effects of Scotland's healthcare waste with a focus on pharmaceuticals." Thesis, Glasgow Caledonian University, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.517954.

Ferreira, Eduardo Rodrigues [UNESP]. "Gestão e gerenciamento dos resíduos de serviços de saúde em Presidente Prudente - SP." Universidade Estadual Paulista (UNESP), 2007. http://hdl.handle.net/11449/99879.

Ferreira, Eduardo Rodrigues. "Gestão e gerenciamento dos resíduos de serviços de saúde em Presidente Prudente - SP /." Presidente Prudente : [s.n.], 2007. http://hdl.handle.net/11449/99879.

Shehab, Salman Ali Salman. "Enhancing environmental sustainability of healthcare facilities : a system dynamics analysis approach." Thesis, Brunel University, 2017. http://bura.brunel.ac.uk/handle/2438/15593.

Raila, Emilia Mmbando. "Climate Change Implications for Health-Care Waste Incineration Trends during Emergency Situations." ScholarWorks, 2015. https://scholarworks.waldenu.edu/dissertations/242.

Skoog, Marcus, and Adam Backman. "Replacing waste streams in the healthcare industry by applied technology : Developing technology for a circular economy." Thesis, Blekinge Tekniska Högskola, Institutionen för maskinteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-19719.

Eriksson, Albert. "Reducing waste from healthcare in a society of mass consumption : Applying PSS for personal protective equipment." Thesis, Blekinge Tekniska Högskola, Institutionen för maskinteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-21088.

Manzi, Sean. "Understanding waste management behaviour in care settings in South West England : a mixed methods study." Thesis, University of Plymouth, 2015. http://hdl.handle.net/10026.1/3501.

Makhura, R. R., S. F. Matlala, and M. P. Kekana. "Medical waste disposal at a hospital in Mpumalanga Province, South Africa: implications for training of healthcare professionals." Department of Public Health, Faculty of Health Sciences, University of Limpopo, Sovenga, South Africa, 2016. http://hdl.handle.net/10386/1571.

Rodrigues, Marlos André Silva. "Modelo de integração de informação entre sistemas isolados para implementação de aplicações de Healthcare." Universidade Federal do Amazonas, 2016. http://tede.ufam.edu.br/handle/tede/5599.

Nabiyouni, Nasim. "A Lean Six-Sigma Approach to Red Bag Waste Management in Hospitals." University of Toledo / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=toledo14810384664442.

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Masilela, Mapula Priscilla. "The development and institutionalisation of knowledge and knowledge-sharing practices relating to the management of healthcare risk waste in a home-based care setting." Thesis, Rhodes University, 2017. http://hdl.handle.net/10962/13142.

Esteves, Roger Vinicius Rosa. "Análise do sistema de gerenciamento dos resíduos de serviços de saúde pérfuro-cortantes nos municípios da Bacia Hidrográfica do Rio dos Sinos." Universidade do Vale do Rio dos Sinos, 2010. http://www.repositorio.jesuita.org.br/handle/UNISINOS/4282.

Svensson, Ivan, and Elin Berglund. "At the heart of it all : A value stream mapping of the heart emergency at Danderyds Sjukhus AB." Thesis, KTH, Industriell ekonomi och organisation (Inst.), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-170535.

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Martini, Adriana Amaral. "Estudo de alternativa de valorização de resíduos de serviços de saúde advindos de processo de desinfecção por desativação eletrotérmica (ETD)." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/6/6139/tde-06012017-110356/.

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Silva, Ubiratan Amorim da. "Implantação de células experimentais para a avaliação de codisposição de resíduos sólidos de serviço de saúde e resíduos sólidos domiciliares: resultados preliminares." Universidade do Estado do Rio de Janeiro, 2011. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=3424.

Ribeiro, Eliane de Oliveira Aranha. "Resíduos sólidos de saúde: diagnóstico e possibilidade de aplicação da logística reversa em uma Policlínica Odontológica." Universidade Federal do Amazonas, 2016. http://tede.ufam.edu.br/handle/tede/5533.

Sahlén, Decibell. "Makt och hierarkier inom källsortering : En studie som undersöker källsortering inom äldreomsorgen." Thesis, Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-66927.

Ventura, Katia Sakihama. "Modelo de avaliação do gerenciamento de resíduos de serviços de saúde (RSS) com uso de indicadores de desempenho: estudo de caso - Santa Casa de São Carlos-SP." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-19072009-120104/.

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Tadesse, Menelik Legesse. "Healthcare waste management, quantification and intervention in Addis Ababa City Administration health bureau public health facilities." Thesis, 2019. http://hdl.handle.net/10500/26614.

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• Published: 15 March 2024

Metagenomic insights into the wastewater resistome before and after purification at large‑scale wastewater treatment plants in the Moscow city

• Shahjahon Begmatov 1 ,
• Alexey V. Beletsky 1 ,
• Alexander G. Dorofeev 2 ,
• Nikolai V. Pimenov 2 ,
• Andrey V. Mardanov 1 &
• Nikolai V. Ravin 1  

Scientific Reports volume  14 , Article number:  6349 ( 2024 ) Cite this article

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• Antimicrobials
• Microbial communities
• Industrial microbiology

Wastewater treatment plants (WWTPs) are considered to be hotspots for the spread of antibiotic resistance genes (ARGs). We performed a metagenomic analysis of the raw wastewater, activated sludge and treated wastewater from two large WWTPs responsible for the treatment of urban wastewater in Moscow, Russia. In untreated wastewater, several hundred ARGs that could confer resistance to most commonly used classes of antibiotics were found. WWTPs employed a nitrification/denitrification or an anaerobic/anoxic/oxic process and enabled efficient removal of organic matter, nitrogen and phosphorus, as well as fecal microbiota. The resistome constituted about 0.05% of the whole metagenome, and after water treatment its share decreased by 3–4 times. The resistomes were dominated by ARGs encoding resistance to beta-lactams, macrolides, aminoglycosides, tetracyclines, quaternary ammonium compounds, and sulfonamides. ARGs for macrolides and tetracyclines were removed more efficiently than beta-lactamases, especially ampC , the most abundant ARG in the treated effluent. The removal efficiency of particular ARGs was impacted by the treatment technology. Metagenome-assembled genomes of multidrug-resistant strains were assembled both for the influent and the treated effluent. Ccomparison of resistomes from WWTPs in Moscow and around the world suggested that the abundance and content of ARGs depend on social, economic, medical, and environmental factors.

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Introduction.

The spread of antimicrobial resistance (AMR) in the environmental microbiome has become one of the frequently noted problems in recent years, along with global climate change, food security and other technological challenges. Numerous studies show that from year to year, in addition to increasing the cost of hospitalization and treatment of patients infected with multidrug-resistant bacteria, the number of deaths of such patients is growing 1 , 2 . Understanding the mechanisms underlying the emergence, selection and dissemination of AMR, and antibiotic resistance genes (ARGs), is required for the development of sustainable strategies to control and minimize this threat. The dissemination of antibiotic resistant bacteria (ARB) and ARGs occurs differently and this process is more active in urban territories rather than in rural ones. The rate of spread of ARGs and ARB in urban areas is obviously determined by the high population density and, as a rule, wastewater which flows from these areas contains both ARG and ARB. Most antibiotics used in medicine, agriculture and the food industry, as well as resistant bacteria, end up in wastewater. Wastewater treatment plants (WWTPs) therefore could provide a comprehensive overview of ARG abundance, diversity and genomic backgrounds in particular region 3 . Moreover, wastewater and WWTPs are places where ARGs and ARB are particularly abundant and are often considered “hotspots” for the formation of strains with multiple resistance and one of the main sources of the spread of AMR in the environment 4 .

Despite numerous studies on the role of WWTPs in resistome diversity and dissemination, each new study is, in terms of time and geography, unique, as many urban areas and countries have not yet been studied. In addition, some studies are dedicated to explore only one component of the wastewater treatment system, such as wastewater, activated sludge or treated effluent, and there is a lack of research that would give a comprehensive view of the diversity and change in the composition of the resistome at different stages of water cleaning, from wastewater to treated effluent, released into the environment.

Usually, wastewater treatment in large facilities takes place in three stages. The first stage includes physical methods of water cleaning, the second stage is microbiological treatment in bioreactors with activated sludge (AS), and the third stage is the final treatment of water and its disinfection. At the second stage, than could be performed using several technologies, microorganisms of AS are used to remove organic matter, ammonium, and (in more complex processes) phosphorus 5 . At this stage, the removal of microorganisms present in the wastewater, including ARB, occurs due to their adsorption on AS particles, which are removed along with excess AS. The efficiency of this process differs for various bacteria and depends on the purification technology used. Therefore, purification technologies directly affect the removal of particular ARGs and ARB, however, this issue was poorly studied 6 .

ARGs representing all known resistance mechanisms have been found in WWTP environments 7 . ARGs for beta-lactams, macrolides, quinolones, tetracyclines, sulfonamides, trimethoprim, and multidrug efflux pump genes have been found in the incoming wastewater, AS, and treated effluent in various countries 7 , 8 . Recently, Munk and coauthors (2022) using metagenomics methods characterized resistomes of 757 urban wastewater samples from 243 cities in 101 countries covering 7 major geographical regions. They reported regional patterns in wastewater resistomes that differed between subsets corresponding to drug classes and were partly driven by taxonomic variation 3 . Although this study did not analyzes the composition of the wastewater resistome after treatment, there are numerous evidences that the prevalence of ARB and ARG in rivers may increase downstream from the point of discharge of treated wastewater into them 9 , 10 . In a study of WWTPs in Germany, 123 types of clinically significant antibiotic resistance genes were found in treated wastewater discharged into water bodies 11 . An analysis of the presence of 30 ARGs at different stages of wastewater treatment at WWTPs in Northern China showed that the content of most ARGs in the treated effluent was lower compared to the influent entering the treatment, although an increase in the abundance of some ARGs and their release into the environment was also observed 12 . A metagenomic analysis of WWTP in Hong Kong revealed seasonal changes in the content of several types of ARG and its decrease in the treated effluent 13 , 14 . Most ARGs were reduced by more than 98% in the treated effluent compared to the wastewater entering the treatment 14 . Some other studies have also reported a decrease in ARGs after wastewater treatment 15 , 16 , 17 . However, in other studies, no changes in the ARG content or even an increase were observed 17 , 18 , 19 . Although there are numerous studies of resistomes in WWTP-related environments the distribution of samples was geographically biased and covered mostly North America, Western Europe, Eastern Asia (mostly China), Australasia, and few places in South America/Caribbean and Sub-Saharan Africa 3 .

In order to expand the geographical coverage and our knowledge about global resistome abundance and diversity, we analyzed resistomes of wastewater before and after treatment at large-scale WWTPs in the city of Moscow (Russia). Although Moscow WWTPs are among the largest in the world and may play an important role in the spread of antibiotic resistance, the resistomes of municipal wastewaters in Moscow have not previously been studied by modern molecular genetic methods. Previously we performed 16S rRNA gene profiling of AS microbial communities at large-scale WWTPs responsible for the treatment of municipal wastewater ion Moscow 5 . Comparison of microbial communities of AS samples from WWTPs in Moscow and worldwide revealed that Moscow samples clustered together indicating the importance of influent characteristics, related to local social and environmental factors, for wastewater microbiomes 5 . For example, due to the relatively low cost of water for household consumption, wastewater in Moscow has a relatively low content of organic matter. Apparently the presence of ARB and ARGs in communal wastewater depends on the frequency of antibiotic use and the range of drugs used. These factors differ in different countries and cities. Therefore, the characterization of the resistome and the role of Moscow WWTPs in the dispersion of ARGs is an important goal. Of particular interest is also the assessment of the impact of wastewater treatment technology on the composition of the resistome and the degree of ARG removal.

Here we present the first metagenomic overview of the composition of resistome of influent wastewater, AS and treated effluent released into the environment at two Moscow WWTPs employing different treatment technologies.

Characteristics of WWTPs and water chemistry

The Lyuberetskiy WWTP complex of JSC “Mosvodokanal” carry out the treatment of wastewater in the city of Moscow with a capacity of about 2 million m 3 per day. This complex consists of several wastewater treatment units (hereafter referred to as WWTPs). They purify the same inflow wastewater but otherwise are independent installations between which there is no transfer and mixing of AS. Two WWTPs implementing different technologies for wastewater treatment were chosen as the objects of study. The first one (LOS) is operated using anaerobic/anoxic/oxic process, also known as the University of Cape Town (UCT) technology. There the sludge mixture first enters the anaerobic zone, where phosphate-accumulating microorganisms (PAO) consume easily degradable organics, then to the anoxic zone, where denitrification and accumulation of phosphates by denitrifying PAO occur, and finally to the aerobic zone, where organic matter and ammonium are oxidized while PAO accumulate large quantities of polyphosphate. The second WWTP (NLOS2) uses a simpler nitrification–denitrification technology (N-DN). In the aerobic zones organics and ammonium are oxidized, while in the anoxic zone nitrate is reduced to gaseous nitrogen. This treatment technology removes organic matter and nitrogen, but was not specially aimed to remove phosphates. The production capacity of LOS is approximately 2 times more than that of NLOS2; there are no other important differences between these WWTPs besides treatment technology.

Sampling and chemical analysis

Wastewater and AS samples were collected in September 2022 and kindly provided by “Mosvodokanal” JSC. The temperature of water samples was about 24 °C. Samples of AS from bioreactors of two WWTPs were taken in 50 ml Falcon tubes (BD Biosciences). Wastewater samples (influent and effluents from two WWTPs) were taken in 5 L plastic bottles. The cells were collected by centrifugation at 3000 g for 20 min at 4 °C.

Wastewater quality values, namely, biochemical oxygen demand (five days incubation) (BOD 5 ), chemical oxygen demand (COD), total suspended solids (TSS), sludge volume index (SVI), ammonium nitrogen (N-NH 4 ), nitrate nitrogen (N-NO 3 ), nitrite nitrogen (N-NO 2 ) and phosphorus (P-PO 4 ) in the influent and effluents of two WWTPs were measured by the specialized laboratory “MSULab” according to the Federal inspection of environmental management’s protocols for chemical analyses of water.

DNA isolation, 16S rRNA gene sequencing and analysis

Total genomic DNA was isolated using a Power Soil DNA isolation kit (Qiagen, Germany). DNA for each sample was isolated in four parallel replicates, which were then pooled. PCR amplification of 16S rRNA gene fragments comprising the V3–V4 variable regions was performed using the universal primers 341F (5′-CCTAYG GGDBGCWSCAG) and 806R (5′-GGA CTA CNVGGG THTCTAAT) 20 . The obtained PCR fragments were bar-coded and sequenced on Illumina MiSeq (2 × 300 nt reads). Pairwise overlapping reads were merged using FLASH v.1.2.11 21 . All sequences were clustered into operational taxonomic units (OTUs) at 97% identity using the USEARCH v.11 program 22 . Low quality reads were removed prior to clustering, chimeric sequences and singletons were removed during clustering by the USEARCH algorithms. To calculate OTU abundances, all reads obtained for a given sample were mapped to OTU sequences at a 97% global identity threshold by USEARCH. The taxonomic assignment of OTUs was performed by searching against the SILVA v.138 rRNA sequence database using the VSEARCH v. 2.14.1 algorithm 23 .

The diversity indices at a 97% OTU cut-off level were calculated using USEARCH v.11 22 . To avoid sequencing depth bias, the numbers of reads for each sample were randomly sub-sampled to the size of the smallest set.

Sequencing of metagenomic DNA, contigs assembly and binning of MAGs

Metagenomic DNA was sequenced using the Illumina HiSeq2500 platform according to the manufacturer’s instructions (Illumina Inc., San Diego, CA, USA). The sequencing of a paired-end (2 × 150 bp) NEBNext Ultra II DNA Library prep kit (NEB) generated from 145 to 257 million read pairs per sample. Adapter removal and trimming of low-quality sequences (Q < 30) were performed using Cutadapt v.3.4 24 and Sickle v.1.33 ( https://github.com/najoshi/sickle ), respectively. The resulting Illumina reads were de novo assembled into contigs using SPAdes v.3.15.4 in metagenomic mode 25 .

The obtained contigs were binned into metagenome-assembled genomes (MAGs) using 3 different programs: MetaBAT v.2.2.15 26 , MaxBin v.2.2.7 27 and CONCOCT v.1.1.0 28 . The results of the three binning programs were merged into an optimized set of MAGs using DAS Tool v.1.1.4 29 . The completeness of the MAGs and their possible contamination (redundancy) were estimated using CheckM v.1.1.3 30 with lineage-specific marker genes. The assembled MAGs were taxonomically classified using the Genome Taxonomy Database Toolkit (GTDB-Tk) v.2.0.0 31 and Genome Taxonomy database (GTDB) 32 .

ARG identification

Open reading frames (ORFs) were predicted in assembled contigs using Prodigal v.2.6.3 33 . ARGs were predicted using the NCBI AMRFinderPlus v.3.11.4 ( https://github.com/ncbi/amr/wiki ) command line tool and its associated database 34 . The predicted protein sequences of all ORFs were analyzed in this tool with parameter “-p”.

Efficiency of wastewater treatment

Two wastewater treatment technologies were used in the investigated WWTPs,—nitrification/denitrification at NLOS2 and more advanced anaerobic/anoxic/oxic UCT process at LOS. LOS removed more than 99.5% of organic matter (according to the BOD5 data) and more than 99.9% of ammonium while the performance of NLOS2 was poorer (Table 1 ). Particularly noticeable differences were observed in nitrate and nitrite concentrations in the effluents suggesting the lower efficiency of denitrification in the NLOS2. Interestingly, although the NLOS2 unit was not designed to remove phosphorus, the concentration of phosphates in the treated effluent at this WWTP is only slightly higher than at LOS. The treated influent at LOS contains fewer solids consistently with lower SVI. Overall, the technology used at LOS plant is more efficient.

Microbiomes of the influent wastewater, activated sludge and treated effluent

The 16S rRNA gene profiling of microbial communities revealed 1013 species-level OTUs (97% identity) in the influent and 1.2–1.7 times more OTUs in the AS and treated effluent samples (Supplemental Table S1 ). The Shannon diversity indices correlated with the number of detected OTUs and increased in the series “influent” – “activated sludge” – “effluent” at each WWTP (Supplemental Table S2 ).

Analysis of the microbiome of wastewater supplied for biological treatment showed that that the most numerous phyla in the microbial community were Firmicutes (28.4% of all 16S rRNA gene sequences), Campylobacterota (28.0%), Proteobacteria (20.9%), and Bacteroidota (10.5%) (Fig.  1 ). These were mainly representatives of the fecal microbiota, which are often found in wastewater. The phylum Firmicutes was dominated by Streptococcaceae (9.7%, mostly S treptococcus sp.), Lachnospiraceae (5.9%), Ruminococcaceae (3.0%), Carnobacteriaceae (1.7%), Peptostreptococcaceae (1.6%) and Veillonellaceae (1.4%). Most of Campylobacterota belonged to the family Arcobacteraceae (26.8%) of the genera Arcobacter (19.9%), Pseudarcobacter (2.5%) and uncultured lineage (4.3%), as well as by sulfur-oxidizing Sulfurospirillum (1.0%). Among the Proteobacteria the most abundant genera were Acinetobacter (7.8%) , Aeromonas (1.8%) and Pseudomonas (1.1%). Most of the identified Bacteroidota were typical fecal contaminants such as members of the genera Bacteroides (2.6%), Macellibacteroides (1.5%), Prevotella (1.4%), and Cloacibacterium (1.2%).

Microbial community composition in the influent, AS and treated effluent samples according to 16S rRNA gene profiling. The composition is displayed at the phylum level. INFL, influent wastewater; AS-LOS, AS at LOS plant; CW-LOS, treated effluent at LOS plant; AS-NLOS2, AS at NLOS2 plant; CW-NLOS2, treated effluent at NLOS2 plant.

Activated sludge of WWTP bioreactors is a complex microbial community consisting of physiologically and phylogenetically heterogeneous groups of microorganisms involved in the removal of major contaminants from wastewater. The composition of AS microbiomes was very different from the microbiome of incoming wastewater (Fig.  1 ). The phyla Campylobacterota (less than 0.5%) and Firmicutes (2–4%) were much less abundant in AS microbiomes. Proteobacteria was the dominant group in the microbiomes of AS (23–40%), but its composition differed from the microbiome of influent wastewater: instead of the fecal microflora (Enterobacterales and others) the AS community harbored lineages involved in the purification processes ( Competibacteraceae , Rhodocyclaceae , Nitrosomonadaceae , etc.). Likewise, Bacteroidota were among the most numerous phyla in AS microbiomes at both LOS (6.5%) and NLOS2 (14.1%), but instead of Bacteroidales mostly comprised Chitinophagales and Sphingobacteriales typical for AS communities. The numerous groups of AS community also included Chloroflexi (22% and 10% in LOS and NLOS2, respectively), Patescibacteria (1.8% and 9.9%), Nanoarchaeota (4.3% and 9.1%), Nitrospirota (3.9% and 7.3%), Verrucomicrobiota and Myxococcota (about 4% in both WWTPs). Bacteria that play an important role in the removal of nitrogen ( Nitrospira and Nitrosomonas ) and phosphorus ( Dechloromonas ), as well as glycogen-accumulating Ca . Competibacter, have been found in large numbers. The abundance of these functional groups is consistent with the high efficiency of nitrogen and phosphorus removal.

The main source of microorganisms in treated effluent is the AS, from which they are washed out; bacteria from the influent water may also be present in minor amounts. Therefore, as expected, the microbiome composition of treated wastewater was similar to that of activated sludge. Consistently, compositions of microbiomes of treated effluent were similar to that of AS samples. However, some differences were observed, in particular, the microbiomes of the treated effluent contained many Cyanobacteria (7.74% and 3.49% for LOS and NLOS2, respectively) which were found in minor amounts both in the influent water and in the ASs (< 0.5%). Probably, these light-dependent bacteria proliferate in the final clarifier and then can be easily washed out with the effluent.

Diversity of resistomes

The results of metagenomic analysis of incoming wastewater revealed 544 ARGs in the assembled contigs, classified into 33 AMR gene families (Table 2 and Supplemental Table S3 ). Among the most numerous were classes A, C, D and metallo- beta-lactamases, rifampin ADP-ribosyltransferase, Erm 23S ribosomal RNA methyltransferase, aminoglycoside nucleotidyl-, acetyl- and phospho-transferases, the ABC-F type ribosomal protection proteins, chloramphenicol acetyltransferase, trimethoprim-resistant dihydrofolate reductase, quaternary ammonium compound efflux SMR transporters, lincosamide nucleotidyltransferases, tetracycline efflux MFS transporters and tetracycline resistance ribosomal protection proteins (Table 2 ). These genes may enable antibiotic inactivation (373 genes), target protection (85 genes), efflux (44 genes) and target replacement (25 genes).

The abovementioned genes confer resistance to most of commonly used drugs: beta-lactams (198 genes), macrolides (74 genes), rifamycin (60 genes), aminoglycosides (51 genes), tetracycline (27 genes), phenicols (27 genes), diaminopyrimidines (19 genes), quaternary ammonium compounds (16 genes), glycopeptides (15 genes), lincosamide (13 genes), fosfomycine (12 genes) and drugs of 11 others classes (Fig.  2 ).

ARGs identified in wastewater and AS samples categorized by drug classes.

About twice less ARGs were identified in AS samples from both WWTPs. Like in the influent, beta-lactamases of classes A, D, and metallo-beta-lactamases were the most numerous, while only a few genes for class C enzymes were found (Table 2 ). Other families of ARGs, numerous in the influent, were also numerous in AS microbiomes. A notable difference between the resistomes of the AS samples is the greater number of rifampin-ADP-ribosyltransferase genes ( arr ) in NLOS2 compared to LOS (63 vs 33). The largest number of arr genes was assigned to Bacteroidota, and the lower relative abundance of this phylum in AS at LOS likely explains these differences. Like in the wastewater, resistance to beta-lactams, macrolides, rifamycin, aminoglycosides, and tetracyclines was the most common (Fig.  2 ). On the contrary, genes for some drug classes were underrepresented in AS resistomes, especially for diaminopyrimidines (3 and 2 genes for LOS and NLOS2, respectively) and glycopeptide antibiotics (2 and 0 genes).

The results of metagenomic analysis of treated effluent showed that the diversity of these resistomes was only slightly higher than that of the corresponding AS samples. This result was expected since the main source of microorganisms in the effluent is activated sludge, from which they are partially washed. However, resistomes of treated effluent at both WWTPs contains about twice more class A beta-lactamase genes than AS samples suggesting less efficient absorption of their host bacteria at AS particles (Table 2 ).

Quantitative analysis of antibiotic resistance genes of WWTP

The results described above provide information on the diversity of resistance genes, but not on their abundance in the metagenomes, which depends on the abundance of corresponding bacterial hosts. To quantify the shares of individual ARGs in the metagenome and resistome, the amounts of metagenomic reads mapped to the corresponding ARGs in contigs were determined. In total, the resistome accounted for about 0.05% of the metagenome of wastewater supplied for treatment, while the shares of resistomes in the metagenomes of AS and treated effluent samples were 0.02% and 0.014% at the LOS and NLOS2 WWTPs, respectively.

Quantitative analysis of the content of individual ARGs in metagenomes showed that the structure of the influent resistome was very different from that of AS and treated effluent. The relative content of ARGs accounting for more than 1% in at least one analyzed resistome is shown in Fig.  3 . The LOS and NLOS2 WWTPs differed significantly from each other, and the differences between the AS and effluent resistomes at each WWTP were much less pronounced.

The relative abundancies of particular ARGs in the resistomes. Only ARGs with shares greater than 1% in at least one sample are shown, all other ARGs are shown as “others”.

The resistome of the influent was not only the most diverse, but also the most even in composition. The shares of none of the ARGs exceeded 5% of the resistome, and the 23 most common ARGs accounted for a half of the resistome. The most abundant ten ARGs were qacE, sul1, ampC, blaOXA, msr(E), erm(B), mph(E), tet(C), aph(3'')-Ib and aph(6)-Id, conferring resistance to antiseptics, sulfonamides, beta-lactams, macrolides, aminoglycosides (streptomycin), and tetracyclines.

AS and treated effluent at LOS plant was strongly dominated by a single AGR type, class C beta-lactamase ampC , accounting for about 45% of their resistomes. This gene was also the most abundant one in the resistomes of AS and effluent at NLOS2 (14.8% and 18.2%, respectively). Apparently it originates from the influent wastewater supplied for treatment where its share in the resistome was 3.2%. AmpC β-lactamases are considered clinically important cephalosporinases encoded on the chromosomes and plasmids of various bacteria (especially Enterobacteriaceae ), where they mediate resistance to cephalothin, cefazolin, cefoxitin and most penicillins 35 . Close homologues of this gene, with a nucleotide sequence identity of 99.8–100%, have been found in plasmids and chromosomes of various Proteobacteria ( Thauera, Sphingobium, Aeromonas etc.). Since in all samples ampC was found in short contigs with very high coverage, it is likely widespread in the genomes of various bacteria in different genetic contexts.

The second most abundant ARG in the resistomes of AS samples was sulfonamide-resistant dihydropteroate synthase ( sul1 ). It accounted for 4–5% of AS and treated effluent resistomes in LOS and for about 11% in NLOS2, while its share in the influent water resistome was about 5%. The sul1 gene is usually found in class 1 integrons being linked to other resistance genes, including qacE 36 . Consistently, sul1 and qacE were found in one contig assembled for the influent water samples and assigned to Gammaproteobacteria. Another sulfonamide-resistance gene, sul2 , was also numerous, accounting for about 2% of the resistomes in the influent and LOS samples, and for about 4% in the AS and water treated at NLOS2.

Since ARGs entering the activated sludge and then into the treated effluent originate mostly from wastewater supplied for treatment, the absolute majority of ARGs present in the influent in significant amounts (more than 0.2% resistome) in were also found in AS and effluent samples. The only exception macrolide 2′-phosphotransferase gene mph(B) accounting for 0.51% in the influent resistome. Likewise, all ARGs accounting for more than 0.2% of resistomes in the treated effluent were present also in the influent.

Potential multidrug resistant strains

One of the most important public health problems is the spread of multidrug resistant pathogens (MDR), which refers to resistance to at least one agent in three or more chemical classes of antibiotic (e.g. a beta-lactam, an aminoglycoside, a macrolide) 37 . Such strains can arrive with wastewater entering the treatment, and also form in AS communities. AS are dense and highly competitive microbial communities, which, along with the presence of sublethal concentrations of antibiotics and other toxicants in wastewater, creates ideal conditions not only for the selection of resistant strains, but also for the formation of multiple resistance through horizontal gene transfer 4 . To identify MDR bacteria, we binned metagenomic contigs into metagenome-assembled genomes (MAGs) and looked for MAGs comprising several ARGs. Only MAGs with more than 70% completeness and less than 15% contamination were selected for analysis: 117, 56, 72, 94 and 121 for influent, AS of LOS, effluent of LOS, AS of NLOS2 and effluent of NLOS2, respectively. Five MAGs of MDR bacteria were identified in the metagenome of the influent, one—in AS of LOS, two—in the LOS effluent and one in the NLOS2 effluent (Table 3 ). These MAGs were assigned to unclassified genus-level lineages of Ruminococcaceae and Cyclobacteriaceae, Phocaeicola vulgatus, Streptococcus parasuis, Ancrocorticia sp., Enterococcus sp., Bacillus cereus and Undibacterium sp.

Disscussion

We characterized the composition of microbial communities and the resistomes of influent wastewater, activated sludge and treated effluent from two WWTPs in city of Moscow, where various biological water treatment technologies are used. Among the predominant bacteria in the influent wastewater we found mainly fecal contaminants of the genera Collinsella , Bacteroides , Prevotella , Arcobacter , Arcobacteraceae , Blautia , Faecalibacterium, Streptococcus , Acinetobacter , Aeromonas and Veillonella 38 , 39 , 40 , 41 , 42 , 43 . Previously, we performed 16S rRNA gene profiling of wastewater before and after treatment at one WWTP (LOS) and revealed that all abovementioned potential pathogens were efficiently removed and their relative abundance in the water microbiome decreased by 50‒100 times 44 . Similar pattern of removal of potential pathogenic bacteria was observed here for NLOS2 where another water treatment technology is used.

An important indicator of the dissemination of ARG is the proportion of the resistome in the entire metagenome before and after wastewater treatment. In the influent, the resistome accounted for about 0.05% of the metagenome, which corresponds to approximately two ARGs per bacterial genome. Approximately the same values are typical for most countries 3 . After treatment, the fraction of the resistome in the wastewater metagenomes decreases, but, surprisingly, only by 2–4 times. However, since the total concentration of microorganisms in treated effluent is approximately two orders of magnitude lower than in raw wastewater, it is likely that the total abundance of ARGs in the treated effluent is significantly reduced.

Apparently, fecal contaminants effectively removed during treatment are not the only carriers of ARG in wastewater, which are also found in bacteria characteristic of activated sludge and thus appearing in the effluents. Unfortunately, due to the high diversity of microbiomes and the tendency of ARG to be present in multiple copies in different genomic environments, most of the contigs containing ARG turned out to be short, which did not allow to define their taxonomic affiliation.

The resistome of influent water includes 26 ARGs, the share of which is more than 1%. Among of them the prevalence of ampC, aadA, qacE, bla, qacF and qacL is specific for Moscow WWTPs, since these genes were not among the 50 most common ARGs according to the results of a worldwide analysis of wastewater resistomes in large cities 3 . Different ARGs were most “evenly” represented in the influent wastewater while in the AS and treated effluent, a clear selection of particular types of ARGs was observed, which obviously reflects a change in the composition of microbiomes. A vivid example is the increase in the proportion of ampC in the resistomes, especially at LOS.

The discovered ARGs can confer resistance to most classes of antibiotics and among the resistomes of the studied WWTPs in the city of Moscow, genes conferring resistance to beta-lactam antibiotics were the most common, they accounted for about 26% of the resistome in the water supplied for treatment (Fig.  4 ). Similar values have been observed for wastewater in some other countries, particularly in Eastern Europe and Brazil, where 20 to 25% of reads were assigned to ARGs conferring resistance to beta-lactams 3 . According to data for 2021, beta lactams accounted for about 40% of the total antibiotic consumption in Russia in the medical sector 45 .

The relative abundancies of ARGs in the resistomes categorized by drug classes.

Like in most wastewater resistomes in different countries, ARGs conferring resistance to macrolides, aminoglycosides and tetracycline were also among the most abundant in wastewater from Moscow (Fig.  4 ). Resistance to macrolides, rather than beta-lactams, was most common in wastewater from most countries in Europe and North America, while in Moscow ARGs to macrolide were the second most common. Macrolides and tetracyclines are also widely used in medicine in Russia (20% and 5% of total antibiotic consumption in 2021, respectively). On the contrary, medical consumption of aminoglycosides in Russia is rather low (< 1% of the total), therefore, the high abundance of relevant ARGs was unexpected. The opposite pattern was observed for quinolones, which make up about 22% of the antibiotics used in medicine, but their ARGs accounted for only about 1% of the resistome. However the main mechanisms of resistance to quinolones, mutations in the target enzymes, DNA gyrase and DNA topoisomerase IV, and increased drug efflux 46 , were not addressed in our study.

A peculiar feature of Moscow wastewater resistome was the high content of resistance genes to sulfonamides (about 9%), which were not among the major genes in wastewater resistomes worldwide 3 . Sulfonamides are synthetic antimicrobial agents that currently have limited use in the human medicine, alone or mainly in combination with trimethoprim (a dihydrofolate reductase inhibitor), in the treatment of uncomplicated respiratory, urinary tract and chlamydia infections 7 , 47 . Different sulfonamide ARGs ( sul1, sul2 and sul3 ) were detected in the wastewater in the some countries, including Denmark, Canada, Spain and China, applying culture dependent, independent and qPCR methods 7 . The opposite picture was observed for streptogramin resistance genes, which were among the ARGs in the majority of resistomes worldwide, but in Moscow wastewater they accounted for less than 1%. This is probably due to the limited use of this drug in Russia.

Another distinguishing feature of the resistome of wastewater in Moscow is the high content of ARGs conferring resistance to quaternary ammonium compounds (QAC), about 9%. It can be explained by the frequent use of these antiseptics in medicine. QACs are active ingredients in more than 200 disinfectants currently recommended for inactivation the SARS-CoV-2 (COVID-19) virus 48 . A recent study showed that the number of QACs used to inactivate the virus in public facilities, hospitals and households increased during the COVID-19 pandemic 49 . Indeed, the results of a study dedicated to the study of wastewater resistome worldwide 3 did not reveal the presence of QAC ARGs in the wastewater, since the samples for this study were collected before the pandemic.

An important issue is the extent to which different water treatment technologies remove ARGs. The effective removal of ARG was primary due to a decrease in the concentration of microorganisms in treated effluent, since the share of resistome in the metagenome after treatment decreased by only 2.6 –3.7 times and the NLOS2 plant appeared to be more effective in this respect. However, compared to LOS, treated effluent at NLOS2 contains approximately twice as much suspended solids, probably due to poorer settling characteristics of the sludge indicated by the higher SVI. Therefore, the overall efficiency of removing ARGs from wastewater at two WWTPs may be similar.

Considering the relative abundances of ARGs in the resistomes, genes conferring resistance to macrolides and tetracyclines were removed more efficiently than beta lactamases, especially ampC , and rifampin ADP-ribosyltransferase genes. The low efficiency of removal of the ampC gene and the increase in its abundance in the resistome after wastewater treatment were previously reported for WWTPs in Germany 50 . Efficient removal of ARGs to macrolides ( ermB, ermF, mph(A), mef(A) ) and tetracyclines ( tet(A), tet(C), tet(Q), tet(W) ) has been reported in a number of studies worldwide 51 . ARGs enabling resistance to sulfonamides, tetracyclines and chloramphenicol were more efficiently removed at LOS than at NLOS2, while the opposite was observed for beta lactamases (Fig.  4 ). The later became the most abundant class of ARGs in the treated effluent.

Metagenomic analysis not only identified resistance genes, but also revealed probable MDR strains based on the analysis of assembled MAGs. We identified 9 such strains in both influent, AS and treated effluent. The real number of MDR strains is probably higher, since only a small fraction of all metagenomic contigs was included in the assembled high quality MAGs.

Phocaeicola vulgatus , (formerly Bacteroides vulgatus ), is a mutualistic anaerobic bacteria commonly found in the human gut microbiome and frequently involved in human infections. The results of whole genome analysis showed presence of blaTEM-1 and blaCMY-2 ARGs, which confers resistant to beta-lactams 52 , 53 . P. vulgatus was also identified as potential host for the transmission of tetracycline ARGs 54 . Streptococcus parasuis is an important zoonotic pathogen that causes primarily meningitis, sepsis, endocarditis, arthritis, and pneumonia in both pigs and humans 55 . A variety of MDR strains of this bacterium have been described. For instance, S. parasuis strain H35 was isolated from a lung sample of a pig in China; several ARGs, including optrA , catQ , erm(B), lsa(E), msr(D), mef(A), mdt(A), tet(M), lnu(B), aadE and two copies of aacA-aphD , were found in the chromosome and cfr(D) was detected on plasmid pH35-cfrD 56 . MDR strain of Bacillus cereus was identified in the effluent water microbiome. This bacterium is known as human pathogen and a common cause of food poisoning with toxin-producing property 57 . Bacillus cereus was isolated from drinking water treatment plant in China and antimicrobial susceptibility testing revealed that it was resistant to cefoxitin, penicillin tetracycline 58 , macrolide-lincosamide-streptogramin (MLSB), aminoglycoside and tetracycline antibiotics 59 . Assembled MAG B.cereus from effluent water contained ARGs conferring to macrolides, beta-lactams, fosfomycin and streptogramin and may be considered as MDR strain. Genomes of members of the genera Streptococcus (AS of LOS) and Enterococcus (influent), not identified at the species level, were found to contain multiple ARGs. Most of species of these genera are opportunistic and true pathogens known for their drug resistance 60 , 61 . One MAG from the influent water metagenome was assigned to uncultured lineage of the family Ruminococcaceae. Members of this family are typical non-pathogenic gut inhabitants, although genomes of some strains could harbor ARGs 62 .

Three MAGs retrieved from influent wastewater microbiome ( Ancrocorticia ) and treated effluent water ( Cyclobacteriaceae and Undibacterium ) were found to contain several ARGs. However, we found no evidences about pathogenic and MDR strains in these taxa. It is possible that these environmental bacteria acquired ARGs via horizontal gene from outside their lineages. WWTPs are an ideal environment for horizontal gene transfer (HGT), since when bacteria are exposed to strong selective pressures, such as the presence of antimicrobials, the horizontal acquisition of ARGs enables genetic diversification and create the potential for rapid gains in fitness 63 .

Conclusions

Metagenome sequencing of the raw wastewater, activated sludge and treated wastewater at two large WWTPs of the Moscow city revealed several hundreds of ARGs that could confer resistance to most commonly used classes of antibiotics.

Resistome accounted for about 0.05% of the wastewater metagenome and after wastewater treatment its share decreased by 3–4 times.

The resistomes were dominated by ARGs encoding resistance to beta-lactams, macrolides, aminoglycosides, tetracycline, QAC, and sulfonamides. A peculiar feature of Moscow wastewater resistome was the high content of ARGs to sulfonamides and limited occurrence of resistance to streptogramins.

ARGs for macrolides and tetracyclines were removed more efficiently than ARGs for beta-lactamases.

A comparison of wastewater resistomes from Moscow and around the world suggested that the abundance and content of ARG in wastewater depend on social, medical, and environmental factors.

Data availability

The raw data generated from 16S rRNA gene sequencing and metagenome sequencing have been deposited in the NCBI Sequence Read Archive (SRA) and are available via the BioProject PRJNA945245.

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Acknowledgements

This work was partly supported by the Russian Science Foundation (Project 22-74-00022 to S.B.).

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Shahjahon Begmatov, Alexey V. Beletsky, Andrey V. Mardanov & Nikolai V. Ravin

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S.B. and N.V.R. designed and supervised the research project; A.G.D. collected the samples and analysed chemical composition of wastewater; A.V.M. performed 16S rRNA gene profiling and metagenome sequencing; S.B., A.V.B., N.V.P., and N.V.R. analysed the sequencing data; S.B. and N.V.R. wrote the manuscript. All authors have read and agreed to the published version of the manuscript.

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Begmatov, S., Beletsky, A.V., Dorofeev, A.G. et al. Metagenomic insights into the wastewater resistome before and after purification at large‑scale wastewater treatment plants in the Moscow city. Sci Rep 14 , 6349 (2024). https://doi.org/10.1038/s41598-024-56870-0

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Fraud, waste and abuse: How some doctors are exploiting Medicare and turning patients into 'cash cows'

When Lisa Crotty discovered a hospital had billed her chronic pain treatments as cerebral palsy/muscular dystrophy procedures, conditions she doesn't have, she was stunned. 

What concerned her more was the attitude of the private hospital's billing department when she alerted it to the extra money it had pocketed from the billing errors.

"They said to me, 'why are you concerned? It's not coming out of your pocket, your health fund is paying'," she said.

Her private health records show the incorrect billing occurred twice, once in October 2023 and again in February this year, which resulted in the overcharging of her private health fund more than $2,000 following a procedure known as nerve ablations, where a portion of the nerve is destroyed or removed to reduce pain.

"I couldn't believe what I heard," she said.

"I was told they would look into it, but I have not heard back."

Lisa is one of several chronic pain sufferers whose medical bills reveal anaesthetists apparently billing for fictitious services and hospitals, anaesthetists and physicians submitting inflated bills.

It follows a Four Corners investigation into the chronic pain industry, which exposed over treatment and questionable billing practices in the multi-billion-dollar sector.

The revelations prompted Federal Health Minister Mark Butler to ask his department to "urgently" investigate the matters further. There are also now urgent calls for reforms.

'He was just lining his own pockets'

Anaesthetist Joanna Sutherland, who chairs the Safety and Quality Committee of the Australian and New Zealand College of Anaesthetists (ANZCA), described the anaesthesia billing system as unfit for purpose and said it was open to misinterpretation and misapplication.

"In my opinion it is in the interests of providers, patients and funders that it be substantially reformed," Dr Sutherland said.

The Four Corners program led to a flood of patients sending questionable billings to ABC investigations.

One patient, who asked not to be named, said he was shocked when his anaesthetist sent him a notice to pay for a service that didn't happen because the surgery was cancelled by the hospital days earlier.

It requested he pay the outstanding amount as his private health fund and Medicare had not paid the bill in full.

He said he called, visited, and wrote to the anaesthetic service in an attempt to understand how a private health fund and Medicare had been billed (and paid) for a service that didn't happen.

"How did the fund even pay for this? How many others have they paid that they shouldn't have? How could it have been paid. How?" he wrote in an email to the clinic last June.

His local politician weighed in and wrote to the clinic, asking for an explanation. The clinic told the politician it had apologised to the patient for the "mess" and said it was still to refund Medicare and the private health fund.

"We will do our very best to resolve the problems with this account as we want the best for our providers and also our patients."

Another patient provided medical and billing records to the ABC that showed his anaesthetist billed for services that were not provided, wrongly billed for more complex services and exaggerated the anaesthetic time, all of which paid more money.

Even before the surgery, the patient's wife — herself, a former practice manager — became worried about the way the anaesthetist was charging.

When she called the anaesthetist's secretary to express her concerns, the response was: "this is how he always does it" but then agreed to refund a $500 fee the patient had paid.

Later, the patient noticed that two pre-anaesthetic consultations had been billed and the patient's wife confirmed that neither had lasted longer than 15 minutes, which is a Medicare requirement for the items billed.

"Most people certainly wouldn't have an understanding of these funding arrangements," the former practice manager said.

"This anaesthetist tried to make out like he was doing us a favour … but he was just lining his own pockets when in fact it was an act of fraud against Medicare and our health fund.

"And it's the arrogance too. They think they're untouchable."

In a statement, the Australian and New Zealand College of Anaesthetists (ANZCA) said the overwhelming majority of anaesthetists and specialist pain medicine physicians operate with integrity and make every effort to comply with increasingly complex billing requirements.

It said as the body representing the professional standards of specialist anaesthetists and specialist pain medicine physicians, it supports an investigation of any allegations of overservicing, wastage, and unprofessional behaviour by the relevant federal regulatory authorities.

Red flags in billing data

The Four Corners investigation into the pain industry included a report prepared by international healthcare fraud, waste, and abuse organisation, Kirontech and local medical billing organisation Synapse, which assessed the billing records of more than 23,000 de-identified private health insurance patients who underwent spinal surgery in Australia between November 2017 and May 2023.

The report didn't look at the full medical records, only the private health bills, but it found many red flags in the data, suggesting there was a problem with misbilling including billing for services not provided, billing for longer services than provided, and billing for more complex services than those provided.

The ABC asked Dr Sutherland and medical billing expert Margaret Faux, a registered nurse and lawyer with a PhD in Medicare, who runs Synapse, to review the medical records, Medicare and private health fund records of three chronic pain patients.

These patients were Trudi King, Teresa Burbery, and Jason Parker, who were all featured in the Four Corners investigation in early April.

They described their findings of the three's billings as "troubling" and consistent with the trends found in the Kirontech/Synapse report.

They said in each of the three patients, every anaesthesia bill they reviewed raised concerns.

"One hundred per cent of the anaesthetic claims we reviewed were questionable," they said.

In the case of Ms Burbery, who was left paralysed after her pain specialist struck her spinal cord during a procedure for a trial spinal cord stimulator, her medical records suggest the anaesthetist billed and was paid a higher rebate on her private health fund bill by saying she had "severe systemic disease" that limits her daily life, which didn't match her medical records.

This was confirmed by Ms Burbery and the anaesthetist's own documentation in the medical records.

"This was a classic example of what the medical records say and what was billed being two completely different things," Dr Faux said.

"Neither Medicare nor the private fund were in the room when the service took place, so they have no way of knowing the truth. The system is trust-based and therefore very vulnerable to abuse."

Dr Sutherland said the anaesthesia bills she reviewed with Dr Faux demonstrate what is happening in the current overly complex system.

"What you want is a system which basically needs no external policing. Inconsistencies or mistakes in billing should be immediately apparent to the provider or the payer through a forcing function or something where the computer says no, so it self-regulates," Dr Sutherland said.

An appalled Ms Burbery said the findings were "absolutely shocking".

"I really hope it's investigated as a whole," she said.

'I was a cash cow'

Jason Parker's health records raised similar concerns, including apparently fictitious billing and exaggerating of complexity by anaesthetists on at least three occasions between 2019 and 2023, when he had 10 spinal cord stimulator-related procedures after a work accident years earlier damaged his back.

Dr Sutherland and Dr Faux noted a series of pre-anaesthesia consultations claimed in 2022 and 2023, where there was no evidence in the medical records that a consultation occurred. They spoke to Mr Parker, who confirmed there was no consultation on each of three occasions, no history taking or examination by the anaesthetist.

They also noted the anaesthetist charged a billing item that said Mr Parker had "severe systemic or significant disease", which was not supported in his medical records, but paid more.

Mr Parker confirmed his health status at the time of the procedure was not limited by any severe systemic or significant disease.

"Not only was I left traumatised as a result of these brutal surgeries, I was left realising that I was a cash cow for the financial benefit of the practice," Mr Parker said.

"It's a travesty that this continues and the pain industry profits greatly from this process. It has to be seen, investigated and to end."

No evidence of psychosocial history

An audit of Trudi King's experience in an intensive care unit in 2021 uncovered what appears to be even more dubious billing by several anaesthetists and other doctors at a private hospital in NSW.

Much of the questionable billing took place when Ms King was sedated and ventilated and in a coma after spinal fusion surgery went horribly wrong.

Dr Sutherland and Dr Faux said on one occasion a pre-anaesthesia assessment did not meet Medicare requirements.

"There was no evidence of a documented management plan, nor was it consistent with a consultation lasting 15-30 minutes," they said.

They noted other anaesthetic bills that didn't match the medical records included a 45-minute consultation and management plan, while Ms King was in a coma.

"The assessment documentation in the medical records consisted of five words: Complex, IPPV, Sedated and two illegible words," they said.

They also found that one anaesthetist, in addition to billing for a pre-anaesthetic consultation that did not meet Medicare requirements, also billed an advanced surgery service, but the surgery performed did not meet the definition of "advanced" in their view.

They noted that a neurologist and a geriatrician each separately billed Ms King's health fund for a 45-minute consultation and management plan, which required a psychosocial history and medication review.

"We can find no evidence in the medical records of any psychosocial history, no evidence of comprehensive multi or detailed single organ system assessment, no formulation of differential diagnoses, no evidence of comprehensive management plan of significant complexity," they said.

The findings shocked Ms King.

"I feel violated … I trusted them," the grandmother of two said.

"I trusted the private health sector and doctors but it's just about money and that makes me violently ill. It makes me feel sick they would do that. How has it gone on so long that no one has questioned this before?"

Misbilling concerns raised seven years ago

Dr Sutherland said most concerning was the questionable billing they found in the three patients' records were some of the same problems outlined in a 2017 report released by the Medicare Benefits Schedule (MBS) Review Taskforce Anaesthesia Clinical Committee, which she chaired.

"Here we are seven years later, and the problems appear to have worsened at significant cost to taxpayers," Dr Sutherland said.

The taskforce, completed during the Turnbull government, reviewed more than 500 Medicare items related to anaesthesia, which accounted for more than $528 million in benefits.

Of the more than 60 recommendations that were made, many were not accepted or significantly watered down after sector feedback.

Dr Sutherland and Dr Faux urged the federal government to revisit some of the 2017 MBS taskforce recommendations, including a reform of the anaesthesia billing system.

They also called on the government to give the Medicare regulator, the Professional Services Review (PSR), additional powers to have the discretion to launch its own investigations, starting in the area of chronic pain and spinal interventions, including anaesthesia and other related services.

ANZCA said it supports the work of the PSR in investigating inappropriate practices in Medicare billing.

"Any changes to the referral process would require widespread consultation and legislative change," it said.

Private Healthcare Australia chief executive Rachel David said she was concerned by the misbilling and asked the government to urgently amend the law to enable the sharing of data between funds and Medicare in a bid to reduce wasteful or fraudulent billing.

Under the current laws, health funds and Medicare can't share data and can therefore only see part of the billing picture, which makes it harder to detect misbilling, which is draining our health system.

The Four Corners exposé into the multi-billion-dollar chronic pain industry found the sector had become a breeding ground for exploitation.

Kirontech chief medical officer and trained anaesthetist Simon Peck has been working in this arena for more than 20 years and said fraud, waste and abuse was a problem in every healthcare system he has looked at without exception.

"The patterns are remarkably predictable," he said.

"So much so I used to say to the sceptics 'If you say there is no problem it means you haven't actually looked. And the more times that you deny that you have a problem the bigger it will be when you eventually do look.'"

He said he is yet to be wrong.

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'I'm so sorry': Teresa had a minor procedure to treat her chronic pain. The surgeon struck her spinal cord

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National News | Missouri man confesses to strangling…

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National News | Missouri man confesses to strangling 72-year-old wife because he couldn’t afford medical care

Ronnie Wiggs was charged with second-degree murder in connection with the death of his wife, who died Saturday in the Kansas City suburb of Independence. He made his initial court appearance on Monday and a hearing was set for Thursday to review his $250,000 bond.

The victim’s name has not yet been released. She was at Centerpoint Medical Center on Friday to get a new port for her dialysis when she suddenly became unresponsive , according to a probable cause affidavit. Hospital staff were able to regain her pulse, but ultimately determined she was braindead and made arrangements to harvest her organs.

She was formally pronounced dead on Saturday and her husband left the hospital shortly thereafter. Wiggs later returned to the medical facility with the woman’s son, where workers heard him say, “I did it, I killed her, I choked her,” according to the affidavit.

A witness later pointed out injuries on the victim’s neck that seemed suspicious , according to the court document. She also suffered a fresh wound in the middle of her throat.

Wiggs was arrested at the scene and later confessed to his wife’s murder, telling authorities that he covered her nose and mouth to keep her from screaming while he strangled her, the statement said. He added that he was depressed and couldn’t handle the caregiving and bills. He further admitted to a previous attempt to kill her while she was at a rehabilitation facility, but she woke up and told him stop, according to court documents.

Wiggs also said he planned other murder attempts in the past, but he did not follow through because his wife had been hooked up to monitors at the time.

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