ISOLATION, MOLECULAR IDENTIFICATION AND ANTIMICROBIAL SUSCEPTIBILITY PROFILING OF ESCHERICHIA COLI O157:H7 STRAIN ISOLATED FROM ANIMAL-ORIGIN FOODS IN HAWASSA AND YIRGALEM, SIDAMA, ETHIOPIA.

Abstract

Escherichia coli O157:H7, an important foodborne pathogen, posing serious public health concern globally. This study conducted from December 2022 to July 2023 with the aim to isolate, molecularly identify and evaluate the antimicrobial susceptibility profiles of Escherichia coli O157:H7 isolated from animal-origin foods including beef, raw milk and fish in Hawassa and Yirgalem towns of Sidama region, Ethiopia. In this study, a total of 298 different samples were collected and analyzed for isolation and identification of Escherichia coli O157:H7 using culture, biochemical tests and PCR analysis. PCR analysis showed that Escherichia coli O157:H7 was isolated from 3.7% of the total samples of which 5.6% and 6.25% were isolated from beef and fish samples, respectively, and no Escherichia coli O157:H7 isolate was observed from milk samples. The observed isolation rate among the different food type samples was statistically significant (p = 0.036). It was revealed that meat samples collected from butcher shops were found to be more (7.6%) contaminated by Escherichia coli O157:H7 than samples from abattoirs (3.4%) (p = 0.445). Regarding fish samples, contamination level was greater in Nile tilapia (8.1%) than Catfish. Similarly, higher (7.3%) contamination was observed from samples collected from Gudumalle fish landing site than other sites. Moreover, fish skin was the more (8.6%) contaminated organ than fish muscle (3.4%). Antibiotic susceptibility test demonstrated that all Escherichia coli O157:H7 isolates exhibited 100% susceptibility to ciprofloxacin, nalidixic acid, chloramphenicol, cephalothin, ceftazidime, ceftriaxone, tetracycline, and gentamicin whereas a 81.8%, 45.5% and 100%resistance was observed in amoxacillin, streptomycin and clindamycin, respectively. The multidrug resistance observed in 45.45% of isolates with the calculated MDR index of 0.27, and no extended-spectrum beta-lactamase (ESBL) producing isolates were detected. The findings highlight the need for stringent hygiene practices and effective monitoring of animal origin foods to minimize the risk of public health threats.