Abstract
Background: Wastewater treatment facilities may be hotspots for antimicrobial resistance as they release into the environment antimicrobial compounds in the form of effluents from households, hospitals and pharmaceutical facilities, and in agricultural run-off, combined with direct contact between natural bacterial communities and discharged resistant bacteria, is driving bacterial evolution and the emergence of more resistant strains. In Gaborone, urban wastewater treatment plants may play a major role as important reservoirs of human and animal commensal bacteria, in which antibiotic resistance determinants and/or organisms persist in the final effluent and are released to the environment. Objectives: To investigate the prevalence and antimicrobial resistance patterns of E. coli isolated from Glen Valley WWTP effluents and receiving rivers in Gaborone, Botswana. Methodology: This was a cross-sectional quantitative study that sought to investigate the prevalence and antimicrobial resistance (AMR) of Escherichia coli isolated from Glen Valley WWTP and receiving water bodies in Gaborone. A sample size of 311 wastewater samples was used, with a 95% confidence interval and a cluster size of 1.0. (EpiInfo Version 7.2.2.6). Results: A total of 311 wastewater samples were collected in various sampling sites, and 289 (92.6%) were positive for E. coli, while the remainder (7.1%; n=22) were negative or had inconclusive results. Average bacterial counts were 2.36 x 10^5 CFU/ml with an average Log CFU/ml of 4.7763. The highest antibiotic resistance was observed with Ampicillin (30.11%), followed by Cefazolin (27.9%) and Cotrimoxazole (25.08%). In comparison, lower antibiotic resistance was observed with Cotrimoxazole (11.25%), Ciprofloxacin (9.65%) and Ciprofloxacin (9.32%). Conclusion: The results of this study indicated that effluent from the wastewater treatment plant (WWTP) discharged into the receiving water sources may have contained high bacterial counts and the E. coli isolated from the effluent showed extensive antibiotics resistance, thereby suggesting a possibility of inadequate treatment processes in the WWTP resulting in effluents of unacceptable quality. However, these observations could be due to other causes or factors like contamination by sewer overflow from other sources. Environmental surveillance of wastewater may also be helpful in detecting resistant E. coli and ARGs before clinical cases rise, acting as an early warning system. Patterns of resistance in wastewater reflect community antimicrobial use and can supplement clinical AMR data. There is a need for the establishment of routine sampling and antibiotic susceptibility testing (AST) of wastewater E. coli to inform national AMR trends.