Prevalence and antibiotic resistance of Escherichia coli O157:H7 in raw sheep milk in different regions of Khuzestan province in 2022

<p style="text-align: left;"><em>Escherichia coli</em> O157:H7 is a significant foodborne pathogen responsible for gastroenteritis, with low infectious doses, and as an enterohemorrhagic strain, it can cause hemorrhagic dysentery. Raw milk, including sheep milk, is a known source of contamination with this pathogen, posing a potential risk for severe human infections. This study aimed to evaluate the potential of raw sheep milk as a vector for the transmission of <em>E. coli</em> O157:H7 and its associated health risks. A total of 114 raw sheep milk samples were collected in Khuzestan province over four months (April&ndash;July 2022). After biochemical assays, the isolates were identified by using specific primers targeting the <em>O157</em> (<em>rfb</em>), <em>H7</em> (<em>flic</em>), <em>stx1</em>, and <em>stx2</em> genes for identification. The study confirmed the isolation of <em>E. coli</em> O157:H7 from 3 samples (2.63%). Antibiogram was then conducted on the confirmed isolates. The results revealed that all isolates were 100% susceptible to imipenem, ceftazidime, and ceftazidime-clavulanic acid. Sixty-six percent of the isolates were susceptible to ciprofloxacin, gentamicin, trimethoprim-sulfamethoxazole, while 33% showed susceptibility to nalidixic acid and nitrofurantoin. None of the isolates were susceptible to ampicillin or clindamycin, indicating significant resistance to these antibiotics. The contamination of raw sheep milk with <em>E. coli</em> O157:H7 in the Khuzestan region suggests that consuming raw sheep milk may be associated with an increased risk of infections caused by this pathogen.