New multi-source waste co-incineration and clustering park operating model for small- and medium-sized city: A case study in China.

With improvements in urban waste management to promote sustainable development, an increasing number of waste types need to be sorted and treated separately. Due to the relatively low amount of waste generated in small- and medium-sized cities, separate treatment facilities for each waste type lack scale, waste is treated at a high cost and low efficiency. Therefore, industrial symbiosis principles are suggested to be used to guide collaborative waste treatment system of multi-source solid wastes, and co-incineration is the most commonly used technology. Most existing studies have focused on co-incineration of one certain waste type (such as sludge or medical waste) with municipal solid waste (MSW), but the systematic design and the comprehensive benefits on a whole city and park level have not been widely studied. Taking the actual operation of a multi-source waste co-incineration park in south-central China as an example, this study conducted a detailed analysis of the waste-energy-water metabolism process of MSW, sludge, food waste, and medical waste co-incineration. The environmental and economic benefits were evaluated and compared with the single decentralized waste treatment mode. The results showed that the multi-source waste co-incineration and clustering park operating model was comprehensively superior to the single treatment mode, greenhouse gases and human toxicity indicators were decreased by 11.87% and 295.74%, respectively, and the internal rate of return of the project was increased by 29.35%. This mainly benefits from the synergy of technical system and the economies of scale. Finally, this research proposed policy suggestions from systematic planning and design, technical route selection, and an innovative management mode in view of the potential challenges.

Potential of solid recovered fuel production from autoclave treated healthcare waste in Sultanate of Oman.

Economic growth has a potential impact on waste generation worldwide. Growing recognition for resources recovery from waste including production of a clean energy has led to the development of standards for, and the generation of, Solid Recovered Fuel (SRF). SRF, according to BS EN ISO 21640 is a fuel prepared from nonhazardous/treated waste to be utilized for energy recovery in incineration or co-incineration plants which meets the classification and specification. The amount of combustible fractions (i.e., plastic, textile and paper) that are present in Healthcare Waste (HCW) and Municipal Solid Waste (MSW) provides an opportunity for SRF production. HCW is defined as clinical waste generated from healthcare facilities. Limited efforts in utilizing treated HCW in production of SRF were noted, despite the fact that high content of combustible fractions, hence the novelty of this research. This research addresses the opportunities of utilizing autoclaved HCW as an alternate fuel; through a detailed chemical and physical analysis of autoclaved HCW collected from the Sultanate of Oman hospital and healthcare facilities. Furthermore, this study examines the possible uses of such materials instead of landfilling. The utilization of treated HCW as an alternative fuel is not only saving the land space, but also reduces the carbon emissions originating from landfilling. This in fact would also support the government in achieving its aspiring goal of the net zero carbon emissions by 2050 through better utilization of these materials in production of SRF as an alternative to fossil fuel combustion. The study revealed that autoclaved HCW appears to have a high quality SRF and is classified as (NCV 4, Cl 3); which complies with the potential end users' specifications. It is estimated that the combined energy output from MSW and HCW combustible fractions could cover about 12.75% of the energy requirements for Oman cement factories.Implications: The results confirm the viability of using autoclave (HCW) as an alternative fuel due to its high thermal energy content. Based on mean Net Calorific Value (NCV) of analyzed HCW that is found around 14 (MJ/Kg (ar)), and the mean Cl level (i.e., 0.814 ± 0.213% (d)); the SRF is classified as (NCV4, Cl 3). This grade is found to be well within the end users accepted range. This opens up the opportunity for creating a market demand for HCW that not only it could boost its recovery, but it could also unlock the value that can generates.

Healthcare waste generation and quantification in public health centres in Addis Ababa, Ethiopia.

BACKGROUND: Healthcare waste produced in healthcare activities entails 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 wastes. Modern method of disposal of healthcare waste have been introduced to most healthcare institutions mismanagement and increased in production in public health centres in Ethiopia is important issues. The aim of the study was to assess the type of healthcare waste generation and quantification in selected public health centres in Addis Ababa, Ethiopia. METHODS: An institution based cross-sectional study were conducted from January to February 2018. Fifteen health centres in Addis Ababa City Administration were selected for this study. Data were collected by using by different color plastic bags (Black plastic bags for non-hazardous wastes, Yellow plastic bags for hazardous wastes and Yellow safety box for needles and Red bags for pharmaceutical wastes and toxic wastes). The collected wastes were measured by weighing scale and were written to data entry sheet. To assure the data quality calibration of weighing scale was made by the standard weight every morning. EPI INFO TM7 and IBM SPSS were used for data entry, cleaning and analysis. RESULTS: The mean healthcare waste generation was 10.64+5.79Kg/day of which 37.26% (3.96+2.20Kg/day) was general waste and 62.74% (6.68+4.29) was hazardous waste from the studies health centres. Total hazardous waste; sharps, infectious, pathological and pharmaceutical wastes constitutes mean (±SD) 0.97 ±1.03, 3.23 ± 2.60, 2.17±1.92 and 0.25 ±0.34 kg/day respectively. Healthcare waste 29.93% and 0.32% were generated from delivery and post-natal case team and nutrition and growth monitoring case team respectively. The annual mean+ SD of healthcare waste generation rate per health centres were 3807.53+ 2109.84 Kg/year. CONCLUSION: The finding in this study showed there was an increased in hazardous healthcare waste in amount as compared to the WHO standard 85% non-hazardous waste and 10% hazardous waste and 5% toxic wastes. The healthcare waste management practices about segregation, collection, transportation and disposal at the source is crucial to decrease in quantity. Generally unselective handling and disposal of healthcare wastes is a concern.

How COVID-19 pandemic affected medical waste management in Türkiye.

Background: The COVID-19 pandemic has caused an increase in medical waste in hospitals. Aims: To evaluate how the COVID-19 pandemic is affecting medical waste management in hospitals in Isparta Province, south-western Türkiye. Methods: We examined medical waste production in 3 different types of hospital (1 private, 1 public and 1 university) in Isparta Province, south-western Türkiye. We compared the number of patients, amount of medical waste and occupancy rates of the 3 hospitals during the pre-pandemic (2019-2020) and pandemic (2020-2021) periods. The data were analysed using SPSS, version 22.0, and statistical significance was set at P < 0.05. Results: During the pandemic, the number of inpatients in the public and university hospitals decreased, while the number in the private hospital increased. The amount of medical waste during the pre-pandemic period was 8.4 kg per person in the public hospital, 7.7 kg per person in the university hospital and 6.3 kg per person in the private hospital. During the pandemic, these amounts were 14.2 kg, 10.1 kg and 7.6 kg per person, respectively. Conclusion: There was a significant increase in medical waste during the COVID-19 pandemic. Health institutions in Isparta Province, Türkiye, need to review their medical waste management strategies to better manage the increased waste.

A review of the applicability of Environmental Management Systems in waste management in the medical sector of Zimbabwe.

Environmental Management Systems (EMS) are currently the cornerstone of achieving sustainability globally. Nevertheless, the question is applicability of EMS in the medical sector. Hence, the review focused on applicability of EMS in medical waste management Zimbabwe. EMS involves overall processes that facilitate reduction of dire impacts of company's activities while increasing performance. EMS framework consists of environmental policy, planning, implementation, checking, review and improvement stages. To examine applicability of EMS in management of medical sector waste, published secondary sources with information related to the topic were utilised. Analysis of strengths and opportunities of EMS was used as a base to examine its applicability in medical waste management. Zimbabwean medical sector consist of hospitals and primary healthcare facilities. Medical waste includes pathological, pharmaceutical, cytotoxic, radioactive, chemical, sharp, infectious and general waste. However, twenty-first century witnessed expansion of medical institutions to accommodate COVID-19 patients, resulting in generation of construction and demotion waste. Medical institutions in Zimbabwe are accountable for solid waste management at generation source although municipalities are responsible for conveying solid waste to landfills. Solid waste from medical sector is disposed through traditional strategies namely landfilling, incineration, open pits and open burning, resulting in water, air, and soil contamination. However, EMS can reduce quantity of solid waste disposed through waste reuse, recycle and recovery. Moreover, achievement of integrated approach, effective legislation, policies and inclusive participation in medical waste management is adopted through use of EMS. Therefore, EMS were utilised to develop an integrated sustainable medical waste management model to achieve sustainability.

A Comparative Analysis of Hazardous Medical Waste Management Compliance Before (2019) and During (2020) the COVID-19 Pandemic in Indonesia.

Background: As a producer of hazardous waste, hospitals have the responsibility to manage the waste they produce. Hospital non-compliance in managing hazardous waste can have a negative impact on the environment and public health, especially during the COVID-19 pandemic, when the amount of hazardous waste produced by healthcare facilities is increasing. To protect the environment and public health from the negative impact of hazardous medical waste, this study was conducted to determine the level of compliance of hazardous waste management in hospitals in Indonesia before and during the COVID-19 pandemic, from 2019 to 2020. Study design: Cross-sectional. Methods: This study was conducted at 343 hospitals in Indonesia using secondary data obtained from Sikelim (Medical Waste Management Information System), which is owned and operated by the Ministry of Health. The data have been analyzed using chi-square tests and logistic regressions of the determinant model. Results: There was an increase in the level of compliance of hazardous waste management in hospitals from 82% to 86% during the pandemic. Furthermore, the availability of environmental documents and environmental health units were determinant factors of hazardous waste management compliance by hospitals before the pandemic in 2019. The only factor in 2020 was the availability of environmental health units. Conclusions: Despite the good level of compliance, additional efforts are needed to increase the activities of the treatment of hazardous medical waste by hospitals, as before the pandemic (i.e., in a normal situation) only 8% of hospitals was able to independently manage hazardous medical waste using authorized incinerators, a percentage that was reduced to 6% during the pandemic.

Study on the process of medical waste disinfection by microwave technology.

Microwave sterilization technology is an environmentally friendly non-incineration disposal method for medical waste. The core sterilization technology of "microwave sterilization, steam makes the system heat up quickly" was adopted to build a microwave sterilization screw conveyor system that can continuously and dynamically type microwave sterilization. The platinum resistance temperature sensor is used to measure the temperature of the steam at the outlet of the system and the temperature of the material at the outlet. The microwave sterilization process for medical waste was studied on the microwave sterilization test platform, and the influence and regularity of three factors on the microwave sterilization effect were explored and the microwave sterilization process was optimized using the orthogonal test method. Bacillus subtilis var. black spore (ATCC 9372) was used as the detection object of microwave sterilization effect, and the sterilization rate was calculated by the total number of colonies after culture. The results show that, microwave sterilization time has the greatest influence on sterilization effect, the greater the microwave power, the longer the sterilization time, the higher the water content, the higher the sterilization rate. The orthogonal test results show that the optimal process parameters of the microwave sterilization system are the microwave power of 22 kW, the sterilization time of 480 s, and the moisture content of 90%, the sterilization rate is 99.9996%, the sterilization effect is good. When the microwave power is 25 kW or 28 kW, the sterilization time is 480 s or 600 s, and the water content is 90%, the sterilization rate is 100%. Considering the germicidal effect, equipment cost, saving power consumption, shortening the germicidal process time and other comprehensive factors, this process parameter can obtain the best benefit. It can be seen that the use of microwave sterilization technology to treat medical waste is fast and efficient, and does not produce dioxins and other harmful substances, safe and environmental protection, simple operation, excellent sterilization effect.

Hospital waste generation during the first wave of COVID-19 pandemic: a case study in Delhi.

In this study, the hospital waste generation rates and compositions in Delhi were examined temporally and spatially during the first COVID-19 wave of April 2020. A total of 11 representative hospitals located in five districts were considered. The pre-COVID hospital waste generation rates were relatively consistent among the districts, ranging from 15 to 23 tonne/month. It is found that the number of hospital beds per capita may not be a significant factor in the hospital waste quantity. Strong seasonal variations were not observed. All districts experienced a drastic decrease in generation rates during the 1-month lockdown. The average rates during the COVID period ranged from 12 to 24 tonne/month. Bio-contaminated and disposable medical product wastes were the most common waste in Delhi's hospitals, representing 70-80% by weight. The changes in waste composition were however not spatially consistent. The lockdown appeared to have had a higher impact on hospital waste generation rate than on waste composition. The findings are important as the design and operation of a waste management system are sensitive to both waste quantity and quality. Waste records at source helped to minimize waste data uncertainties and allowed a closer examination of generation trends.

Assessment of medical waste generation, associated environmental impact, and management issues after the outbreak of COVID-19: A case study of the Hubei Province in China.

COVID-19 greatly challenges the human health sector, and has resulted in a large amount of medical waste that poses various potential threats to the environment. In this study, we compiled relevant data released by official agencies and the media, and conducted data supplementation based on earlier studies to calculate the net value of medical waste produced in the Hubei Province due to COVID-19 with the help of a neural network model. Next, we reviewed the data related to the environmental impact of medical waste per unit and designed four scenarios to estimate the environmental impact of new medical waste generated during the pandemic. The results showed that a medical waste generation rate of 0.5 kg/bed/day due to COVID-19 resulted in a net increase of medical waste volume by about 3366.99 tons in the Hubei Province. In the four scenario assumptions, i.e., if the medical waste resulting from COVID-19 is completely incinerated, it will have a large impact on the air quality. If it is disposed by distillation sterilization, it will produce a large amount of wastewater and waste residue. Based on the results of the study, we propose three policy recommendations: strict control of medical wastewater discharge, reduction and transformation of the emitted acidic gases, and attention to the emission of metallic nickel in exhaust gas and chloride in soil. These policy recommendations provide a scientific basis for controlling medical waste pollution.

Disposal habits and microbial load of solid medical waste in sub-district healthcare facilities and households in Yilo-Krobo municipality, Ghana.

The study aimed to assess disposal practices and quantify the microbial load present in SMW from ten sub-district level healthcare facilities and 385 households in Yilo Krobo municipality, Ghana. Disposal of solid medical waste (SMW) was assessed by questionnaire-based surveys, unstructured interviews and field observations. Microbiological analysis identified species and counts of bacteria present in SMW from both sources. Sociodemographic factors influencing the method of SMW disposal in households were evaluated using logistic regression analysis, with statistical significance set at p<0.05. Open burning (29%), burying (25%) and disposal at a dumpsite (49%) were common methods used by households to discard SMW. SMW disposal at a dumpsite was associated with age of respondents in households. Older people (50+ years) were three times more likely to place SMW in household waste later discarded at a dumpsite, compared to younger persons (20-30 years) [a0R, 95%CI = 3.37, 1.41-8.02]. In sub-district level healthcare facilities, open burning and burying were the most common methods used. Bacillus subtilis, Klebsiella pneumonia, Pseudomonas aeruginosa, Clostridium tetani, Enterococcus faecalis, Acinetobacter spp. Escherichia coli, Bacillus cereus and Enterococcus faecium) were bacteria identified in SMW recovered from both the healthcare facilities and the households. Klebsiella pneumoniae, Acinetobacter spp. and Clostridium tetani were found exclusively in untreated SMW generated in the healthcare facilities. Bacillus spp. and Pseudomonas spp. were found in one sample of treated SMW. The microbial load in SMW from healthcare facilities and households ranged from 0.036 x 103cfc/mg to 0.167 x 103 cfc/mg and from 0.118 x 103cfc/mg to 0.125 x 103cfc/mg respectively. This highlights the need for institutionalizing appropriate treatment methods in sub-district level facilities or strengthening the linkages with higher level facilities to ensure regular and adequate treatment of SMW. Public guidance on management of SMW generated in households which is context specific should also be provided.

Electrochemical Technologies to Decrease the Chemical Risk of Hospital Wastewater and Urine.

The inefficiency of conventional biological processes to remove pharmaceutical compounds (PhCs) in wastewater is leading to their accumulation in aquatic environments. These compounds are characterized by high toxicity, high antibiotic activity and low biodegradability, and their presence is causing serious environmental risks. Because much of the PhCs consumed by humans are excreted in the urine, hospital effluents have been considered one of the main routes of entry of PhCs into the environment. In this work, a critical review of the technologies employed for the removal of PhCs in hospital wastewater was carried out. This review provides an overview of the current state of the developed technologies for decreasing the chemical risks associated with the presence of PhCs in hospital wastewater or urine in the last years, including conventional treatments (filtration, adsorption, or biological processes), advanced oxidation processes (AOPs) and electrochemical advanced oxidation processes (EAOPs).

Fast-response flow-based method for evaluating 131I from biological and hospital waste samples exploiting liquid scintillation detection.

This paper presents a fast and automatic flow-based method to extract 131I from biological samples and hospital waste, previous to liquid scintillation detection. 131I is a radionuclide extensively used in Nuclear Medicine due to their beta and gamma disintegrations, whereby hospitals have to manage the associated waste generation. The automatic developed system is based on Lab-On-Valve (LOV) flow-technique exploiting Cl-resin (135 mg per extraction). This methodology allows performing sample extractions and measurements on the same day, since the extraction frequency takes 1.4-4 h-1, depending on the analysed sample volume, plus up to 2 h of measurement for each vial. 131I is retained as iodine ion and eluted with sodium sulphide 0.2 mol L-1. The maximum sample volume that can be preconcentrated is 20 mL, reaching an extraction efficiency of 85 ±â€¯5%. The minimum detectable activity (MDA) is 0.05 Bq, showing a precision of 7% RSD (n = 5). Both, biological samples (urine and saliva) and hospital waste samples can be satisfactorily analysed by the proposed system, obtaining recoveries between 90 and 110%. The developed method is then suitable to implement in hospitals, improving the surveillance of the 131I environmental release.

Breakthrough analysis of continuous fixed-bed adsorption of sevoflurane using activated carbons.

The inhalational anaesthetic agent - sevoflurane is widely employed for the induction and maintenance of surgical anaesthesia. Sevoflurane possesses a high global warming potential that imposes negative impact to the environment. The only way to resolve the issue is to remove sevoflurane from the medical waste gas before it reaches the atmosphere. A continuous adsorption study with a fixed-bed column was conducted using two commercial granular activated carbons (E-GAC and H-GAC), to selectively remove sevoflurane. The effect of bed depth (Z, 5-15 cm), gas flow rate (Q, 0.5-6.0 L/min) and inlet sevoflurane concentration (C0, ∼55-700 mg/L) was investigated. E-GAC demonstrated ∼60% higher adsorption capacity than H-GAC under the same operating conditions. Varying the levels of Z, Q and C0 showed significant differences in the adsorption capacities of E-GAC, whereas only changing the C0 level had significant differences for H-GAC. Three breakthrough models (Adams-Bohart, Thomas, and Yoon-Nelson) and Bed-depth/service time (BDST) analysis were applied to predict the breakthrough characteristics of the adsorption tests and determine the characteristic parameters of the column. The Yoon-Nelson and Thomas model-predicted breakthrough curves were in good agreement with the experimental values. In the case of the Adams-Bohart model, a low correlation was observed. The predicted breakthrough time (tb) based on kinetic constant (kBDST) in BDST analysis showed satisfactory agreement with the measured values. The results suggest the possibility of designing, scaling up and optimising an adsorption system for removing sevoflurane with the aid of the models and BDST analysis.

Antimicrobial susceptibility profile of selected Enterobacteriaceae in wastewater samples from health facilities, abattoir, downstream rivers and a WWTP in Addis Ababa, Ethiopia.

Background: Evaluation of antimicrobial susceptibility profile of various bacterial pathogens in the health facilities, abattoirs and related environment is important to assess potential risk of dissemination of resistant pathogens to the environment. There is limited information about antimicrobial susceptibility profile of common Enterobacteriaceae in waste water samples from hospitals, abattoirs and the downstream water bodies in Addis Ababa. The present study assessed antimicrobial susceptibility of bacteria belonging to the family Enterobacteriaceae isolated from wastewater samples (WWS) of two hospitals: Tikur Anbessa Specialized Hospital (TASH) and Minilik II hospital, a wastewater treatment plant (WWTP) and an abattoir, and downstream rivers in Addis Ababa. Results: A total of 54 bacterial isolates belonging to 6 species were identified: E.coli (32%), Salmonella 23%), Klebsiella pneumonia (15%), Enterobacter aerogenes (11%), Citrobacter (7%), Klebsiella oxytoca (6%) and Enterobacter cloacae (6%), respectively. Two strains of Citrobacter spp. isolated from TASH wastewater sample (WWS) were resistant to all 12 antimicrobials tested whereas an E. coli isolate from the same source was resistant to 11 antimicrobials. All isolates were resistant to 2 or more antimicrobials tested. Multi-drug resistance (MDR) to several antimicrobials was recorded, particularly in isolates obtained from hospital WWS and it was more common in Citrobacter and E. coli isolates. Extended spectrum betalactamase (ESBL) production was detected in 27.3% of MDR isolates, all of them obtained from hospital effluents whereas none of the isolates were carbapenemase producers. Conclusion: The present study revealed that Enterobacteriaceae in wastewater from hospitals, abattoir and downstream water bodies are resistant to commonly used antimicrobials. Hospital effluents contained more of MDR bacteria, posing significant public health threat through dissemination to the downstream water bodies.

Healthcare waste management current status and potential challenges in Ethiopia: a systematic review.

OBJECTIVE: During the healthcare delivery process, hazardous wastes can be generated from the health facilities. Improper healthcare waste management is responsible for the transmission of more than 30 dangerous bloodborne pathogens. The aim of this systematic review was to evaluate the healthcare waste management practice and potential challenges in Ethiopia. RESULTS: Electronic databases and direct Google search yielded 1742 articles from which 17 studies met the inclusion criteria. The proportion of hazardous waste generated in Ethiopian healthcare facilities was unacceptably high which ranged from 21 to 70%. Most studies indicated the absence of proper waste segregation practice at the source of generation. Treatment of the healthcare waste using low combustion incinerator and/or open burning and open disposal of the incinerator ash were very common. Lack of awareness from the healthcare staff, appropriate waste management utilities and enforcement from the regulatory bodies were mainly identified as a common factor shared by most of the studies. The healthcare waste management practice in Ethiopian healthcare facilities was unsatisfactory. There should be close supervision of the waste disposal process by the regulatory bodies or other stakeholders.

Torrefaction of herbal medicine wastes: Characterization of the physicochemical properties and combustion behaviors.

To explore the feasibility of using herbal medicine waste (HMW) as solid fuel, HMW was torrefied under different temperatures and atmospheres. The physicochemical properties and combustion behaviors of the torrefied HMW were investigated. Temperature was found to be the most influential factor affecting the torrefaction. Torrefaction improved the hydrophobicity of HMW and decreased the equilibrated moisture uptake from 24.48(0.083) % to 15.22(0.054) %. The HMW samples torrefied under different conditions are easy to ignite. The comprehensive combustibility index (S) of the torrefied HMW increased by 3-5 folds compared to that of the raw sample. In general, the HMW torrefied under lower temperatures and under CO2 and O2 have better flammability. The present results revealed that the torrefied HMW exhibited good combustion characteristics and can thus be used for solid fuel production, such as fuels for co-combustion or raw materials for pelletization.

Analysis of quality and quantity of health-care wastes in clinical laboratories: a case study of Ilam city.

Generation of health-care wastes is one of the major concerns in health-care institutions worldwide due to direct and indirect impact on human health and environment. The purpose of the present work was to estimate the quantity and quality of clinical laboratory wastes in the city of Ilam, Iran. In this cross-sectional study, randomly eight clinical laboratories including five in private sector and three governmental clinical laboratories were selected for sampling according to the purpose of the study. The results showed that the total amount of waste generation was 27,700.90 kg/year. The average amount of health-care wastes generation in Ilam city was 0.2 kg/person/year. The portions of general, pathologic, sharp, infectious, and pharmaceutical and chemical wastes were 37, 5, 2, and 56% (by weight), respectively. As a considerable amount of waste is generated in clinical laboratories of Ilam city, therefore, it is necessary to implement integrated plans for the proper management of these wastes. Thus, sufficient training and education programs must be developed for all clinical staffs and that the existing training and education procedures should also be promoted.

Assessment of extracellular antibiotic resistance genes (eARGs) in typical environmental samples and the transforming ability of eARG.

The emergence and spread of antibiotic resistance has pose a huge threat to both human health and environmental ecosystem. However, little is known regarding the pool of ARGs in extracellular DNA (eDNA). In this study ten ARGs (sul1, sul2, tetW, tetX, ermA, ermB, blaTEM, ampC, cat and cmr) and class I integron (intI1) in the sludge from hospital, pharmaceutical industry, wastewater treatment plant (WWTP), and swine manure, and sediment in urban lake in the form of both eDNA and intracellular DNA (iDNA) were evaluated by quantitative polymerase chain reaction (qPCR). The results showed that every gram of sludge dry weight contained from 7.31 × 103 to 1.16 × 1010 copies of extracellular ARGs (eARGs) and from 1.04 × 105 to 2.74 × 1012 copies of intracellular ARGs (iARGs). The sludge from hospital with the highest ratio of eARGs to total ARGs (11.02-89.63%), followed by the sediment from urban lake, implying that most of the ARGs in these regions were contributed by eARGs. The relative abundance of eARGs were higher than iARGs in sludge from WWTP and pharmaceutical industry, moreover, 1/3 and 5/9 detected eARGs were higher than the ARGs in the iDNA extracted from sludge of hospital and sediment from urban lake, respectively. Furthermore, the transforming ability of eARGs suggesting that adsorbed eARG is more preferentially coupled to the competent cells than free eARG. These findings highlight the need to focus attention on the contribution of eARGs to the dissemination of antibiotic resistance into environment, and also future needs in mitigating the spread of eARGs in the environment.

Biofilms in hospital effluents as a potential crossroads for carbapenemase-encoding strains.

Bacterial resistance to carbapenem, which is mainly due to the successful dissemination of carbapenemase-encoding genes, has become a major health problem. Few studies have aimed to characterize the level of resistance in the environment, notably in hospital wastewater, which is a likely hotspot for exchange of antibiotic resistance genes. In this work, we looked for the presence of imipenem-resistant bacteria and imipenem in the effluent of the teaching hospital of Clermont-Ferrand, France. Selective growth of bacteria from 14-day old biofilms formed in the pipe sewer showed that 22.1% of the isolates were imipenem-resistant and identified as Aeromonas (n = 23), Pseudomonas (n = 10), Stenotrophomonas (n = 4) and Acinetobacter (n = 1). Fifteen of these strains harbored acquired carbapenemase-encoding genes blaVIM (n = 11), blaOXA-48 (n = 2), blaGES (n = 1), blaNDM (n = 1). All isolates also harbored associated resistances to aminoglycosides, fluoroquinolones and/or tetracyclin. S1-nuclease pulsed-field gel electrophoresis analysis of eight selected isolates showed that four of them harbored one to two plasmids of molecular weight between 48.5 Kb and 194 Kb. In vitro transformation assays evidenced the presence of blaVIM and blaNDM on plasmids with the blaVIM harboring 80 Kb plasmid having conjugative capacity. The predicted environmental concentration of imipenem in the hospital effluent was 3.16 µg/L, suggesting that biofilm bacteria are subjected to sub-MICs of imipenem within the effluent. However, no imipenem molecule was detected in the hospital effluent, probably owing to its instability: in vitro assays indicated that imipenem's biological activity was no longer detectable after 45 h of storage. However, the predictive value of the hazard quotient relative to the development of resistance was >1.0 (HQr = 28.9 ±â€¯1.9), which indicates a possible risk. The presence of carbapenemase-encoding genes in hospital effluent biofilm strains and their ability to transfer are therefore a potential hazard that should not be neglected and points to the need for monitoring antibiotic resistance in hospital wastewater.