Abstract:
Background: Globally, the emergence and spread of antibiotic resistance bacteria has been
described as a complex public health challenge. Most hospitals and other clinical settings in
developing countries lack wastewater treatment facilities, such untreated wastewater from their
operations are discharged into water bodies without any form of treatment. This problem is more
critical in low and medium income countries like Ethiopia in which financial resources for the health
care system are low and are likely to be hardest hit by antimicrobial resistance (AMR) both in terms
of public health impact and economic burden.
Objective: To determine isolation rate and Antimicrobial susceptibility profile of Enterobacteriaceae
isolated from wastewater of Jimma Medical Center, Southwest Ethiopia.
Methods: A cross-sectional study was conducted from July to August 2022 on 60 hospital
wastewater samples collected at different intervals during the study period. A convenient and “time
composite-sampling” technique was applied to collect hospital wastewater. Isolation and
identification of Enterobacteriaceae was performed based on standard bacteriological methods.
Antimicrobial susceptibility tests were carried out using Kirby–Bauer disc diffusion method on
Muller Hinton agar. Wastewater physicochemical quality was measured using standards methods.
Data was analyzed using SPSS version 25.0 and Microsoft Excel. Chi-square (χ2) test was used to
evaluate the relationship of dependent and in dependent variables.
Result: Out of 60 samples, 55 (91.7%) samples were positive to one or more isolates and a total of
114 bacteria which are members of Enterobacteriaceae were isolated. The highest isolate within
sampling unit was observed at Laboratory unit, Radiology unit, and Obstetrics and Gynecology ward
and Pooled 22 (19.3%). The isolates were differentiated into seven genera. E.coli 31(51.7%) and
Klebssiella spp. 27(45.0%) were the predominant bacterial isolates. Amoxicillin/Clavulinic acid
(88.4%) showed highest resistance followed by Ampicillin (87.0%), Tetracycline (76.5%) and
Trimethoprim/sulfamethoxazole (71.9%). Least resistance rates were observed against Meropenem
(9.6%) and Chloramphenicol (20.2%). The majority of bacterial isolates 101/114(88.6%) were
multidrug resistant (MDR). The highest average of Dissolved oxygen 0.95±0.04mg/l was recorded at
Point1 and 0.94±0.04 mg/l Mixed2 (Laboratory unit, Radiology unit and Obstetrics and Gynecology
ward). Highest mean of Electrical Conductivity (EC) 7799±991µs/cm were recorded from Kitchen
room/Cafeteria, Laundry room and Surgical ward A), while the lowest EC 1921±1291µs/cm was
recorded from Pooled.
Conclusion: The hospital wastewater contains large amount of bacteria which are members of
Enterobacteriaceae. The majority of bacterial isolates were resistance to commonly prescribed
drugs and most of them are multidrug resistance, which become a reservoir of resistant bacterial
isolate. Therefore, establishing wastewater treatment plant is essential
