Hospital wastewaters: A reservoir and source of clinically relevant bacteria and antibiotic resistant genes dissemination in urban river under tropical conditions

D.M.M. Al Salah, et al. Ecotoxicology and Environmental Safety 200 (2020) 110767 Received 25 November 2019; Received in revised form 21 February 2020; Accepted 14 May 2020
Dhafer Mohammed M. Al Salaha,b , Georgette N. Ngwemec , Amandine Laffitea , Jean-Paul Otamongad , Crispin Mulajie , John Potéa,d,e,∗ a University of Geneva, Faculty of Sciences, Earth and Environmental Sciences, Institute F. A. Forel and Institute of Environmental Sciences, Bd Carl-Vogt 66, CH-1211, Geneva 4, Switzerland b King Abdulaziz City for Science and Technology, Joint Centers of Excellence Program, Prince Turki the 1st St, Riyadh, 11442, Saudi Arabia c School of Public Health, Faculty of Medicine, University of Kinshasa, B.P. 11850, Kinshasa XI, Congo d Université Pédagogique Nationale (UPN), Croisement Route de Matadi et Avenue de La Libération. Quartier Binza/UPN, B.P. 8815 Kinshasa, Congo e Faculty of Science, Department of Chemistry, University of Kinshasa, B.P. 190, Kinshasa XI, Congo
The occurrence and dissemination of antibiotic resistant genes (ARGs) that are associated with clinical pathogens and the evaluation of associated risks are still under-investigated in developing countries under tropical conditions. In this context, cultivable and molecular approaches were performed to assess the dissemination of bacteria and the antibiotic resistance genes in aquatic environment in Kinshasa, Democratic Republic of the Congo. Cultivable approach quantified β-lactam, carbapenem resistant, and total Escherichia coli and Enterobacteriaceae in river sediments and surface waters that receive raw hospital effluents. The molecular approach utilized Quantitative Polymerase Chain Reaction (qPCR) to quantify the total bacteria and the richness of relevant bacteria (Escherichia coli, Enterococcus, and Pseudomonas), and antibiotic resistance genes (ARGs: blaOXA-48, blaCTX-M, blaIMP, blaTEM) in sediment samples. Statistical analysis were employed to highlight the significance of hospital contribution and seasonal variation of bacteria and ARGs into aquatic ecosystems in suburban municipalities of Kinshasa, Democratic Republic of the Congo. The contribution of hospitals to antibiotic resistance proliferation is higher in the dry season than during the wet season (p < 0.05). Hospital similarly contributed Escherichia coli, Enterococcus, and Pseudomonas and ARGs significantly to the sediments in both seasons (p < 0.05). The organic matter content correlated positively with E. coli (r = 0.50, p < 0.05). The total bacterial load correlated with Enterococcus, and Pseudomonas (0.49 < r < 0.69, p < 0.05). Each ARG correlated with the total bacterial load or at least one relevant bacteria (0.41 < r < 0.81, p < 0.05). Our findings confirm that hospital wastewaters contributed significantly to antibiotic resistance profile and the significance of this contribution increased in the dry season. Moreover, our analysis highlights this risk from untreated hospital wastewaters in developing countries, which presents a great threat to public health.

Dr Eric Mafuta Musalu, MPH, PhD
Professeur Associé/Associate Professor
Management et Politique de Systèmes de Santé
Phone: +243 810318918/+243998705153