Prevalence and antimicrobial resistance patterns of Escherichia coli O157:H7 isolated from cattle faeces, beef, and human diarrheic cases in Sebeta, Ethiopia

Abstract

Escherichia coli O157:H7 is an important zoonotic foodborne pathogen that can be transmitted to humans through multiple routes, including the consumption of contaminated raw or undercooked meat. Infection may result in severe clinical outcomes, including hemorrhagic colitis, hemolytic uremic syndrome, renal failure, and death. Identifying potential sources of exposure from both human and animal populations is important for guiding public health interventions. Therefore, this study aimed to isolate E. coli O157:H7 from human and cattle sources and determine its antimicrobial susceptibility profile. A cross-sectional study was conducted in Sebeta, Ethiopia, from November 2019 to May 2020. A total of 392 samples comprising human stool ( n = 125) and animal-derived samples ( n = 267) were collected from diarrheic patients, cattle at an abattoir, and retail meat shops. E. coli O157:H7 was isolated and identified using bacteriological culture, biochemical tests, and latex agglutination. Antimicrobial susceptibility testing was performed for all isolates. In addition, sanitary and hygienic practices at the abattoir and retail shops were assessed through questionnaires and direct observation. Overall, 13 of 392 samples tested positive for E. coli O157:H7, yielding a prevalence of 3.32% (95% CI: 1.78–5.60). The pathogen was detected in 4/120 cattle fecal samples (3.33%; 95% CI: 0.92–8.31), 3/120 carcass swabs (2.50%; 95% CI: 0.52–7.13), 2/27 retail meat samples (7.41%; 95% CI: 0.91–24.29), and 4/125 human stool samples (3.20%; 95% CI: 0.88–7.98). Antimicrobial susceptibility testing showed that all human isolates were susceptible to ciprofloxacin, meropenem, sulfamethoxazole–trimethoprim, nalidixic acid, ceftriaxone, and gentamicin. Resistance was observed to ampicillin, tetracycline, and amoxicillin-clavulanic acid. E. coli O157:H7 was detected in human stool, cattle feces, carcasses, and retail meat samples. The presence of the pathogen in raw meat, together with the practice of raw meat consumption in the study area, highlights a potential public health concern. Although all isolates remained susceptible to several clinically important antimicrobials, resistance to commonly used antibiotics was detected. Strengthening hygienic practices throughtout the meat production chain and promoting continuous surveillance of E. coli O157:H7 and antimicrobial resistance are recommended.