Amandine Laffite
University of Geneva, Switzerland
Title: Hospital effluents, not an exclusive source of emerging contaminant spread in sub-saharian urban rivers
Biography
Biography: Amandine Laffite
Abstract
The contamination of freshwater resources with anthropogenic pollutant is a growing concern of interest because safe and readily available is a need for human. The situation is particularly alarming in developing countries where most rivers and lakes are receiving urban and hospital wastewater without any prior treatment. Furthermore, hospital effluents are known to play a major role in the emergence and the spread of antibiotic resistance genes (ARGs) because they discharge a high rate of antibiotic resistant bacteria (ARBs) in a highly selective environment. Cumulative with the knowledge gaps in antibiotic prescription and the free access to last resort antibiotics, under-developing countries may represent a broth culture to antibiotic resistance emergence, maintenance and dissemination. In this study, we investigate the contamination of sediment and the resistance profile of extending-spectra β-lactamase E. coli (ESBLECs) isolated from 4 urban river subjected to hospital outlet pipes (HOP) discharge in order to determine the effect of HOP discharge on urban river quality and the pattern of antibiotic resistance dissemination. ARGs (blaTEM, blaCTX-M, blaSHV and aadA) and selected bacterial species (i.e E.coli, Enterococcus, Pseudomonas spp.) where quantified in sediments using quantitative PCR (qPCR), toxic metals content were quantified by ICP-MS, and ESBLECs isolates where subjected to pulse-field electrophoresis to assess their clonality and characterized for their resistance to metal and β-lactams resistance. The results highlight the great concentration of toxic metals in sediments (47.87 (Cr), 204 (Cu), 1077 (Zn), 2.07 (Cd), 124.40 (Pb) and 3.94 (Hg), in mg.kg-1 at the HOP reject point), and the high content of FIB and ARGs copy number in all sampling sites including control site and downstream the HOP discharge indicating that hospital effluents are not an exclusive source of the biological contaminant entering the urban rivers. The analysis of ESBLECs profile showed the high diversity of clones disseminated in rivers (150 isolates, 69 pulsotypes), a global resistance to Zn, Cu, Ni and Pb and a high resistance profile against β-lactams (100% resistant to CFM, CEC, ATM, AMP, FEP, CXM, CTX, PRL; 60% to SAM and 37% intermediate to MEM). These findings indicates the human and environmental potential risk link to exposure to these contaminants and the need of developing strategies to limit the spread of these emerging contaminant.