Virulence Factors and Antimicrobial Resistance Patterns of Non-O157 Shiga Toxin-producing Escherichia coli Isolated from Different Sources at Sadat City

Aims: A great concern directed to non-O157 Shiga toxin-producing Escherichia coli (STEC) serotypes due to their public health importance. Detecting the existence, antimicrobial profiles, and virulence repertoire of different STEC serotypes from animals essential for human food are important.

Study Design: This study aimed to investigate the presence of STEC in different hosts, the distribution pattern of stx1, stx2, eaeA, and hlyA genes encoding Shiga toxins 1 and 2, intimin, and enterohemolysin, respectively, and the antimicrobial resistance of the detected serotypes.

Results: A total of 75 samples were collected, 20 fecal samples from broilers, 15 fecal samples from ducks, 20 beef samples, and 20 human urine samples. Escherichia coli was detected at a rate of 60/75 (80%) distributed as;17 (85%), 8 (53.3%), 15(75%), and 20 (100%) from broilers, ducks, human urine, and beef samples, respectively. There was a significant difference between the isolation rates of E. coli from different sources with p<0.05. The prevalent serotypes were O78, O2:H6, O15:H2, and O26: H1. The frequency of stx1 gene was 56/60 (93.3%), stx2 gene was 55/60 (91.6%), the eaeA gene was 35/60 (58.3%), and hlyA gene was 26/60 (43.3%). The most effective antimicrobials were amoxicillin/clavulanic acid and ampicillin with the efficacy of 52/60 (86.6%) for each, while the efficacy of chloramphenicol and doxycycline was 5/60 (8.3%) and 44/60 (73.3%), respectively.

Conclusion: The high frequency of non-O157 Shiga toxin-Producing Escherichia coli from different samples at Sadat City, high prevalence of virulence factors and resistance to chloramphenicol and doxycycline will help in monitoring the distribution of virulent serotypes and contribute to the establishment of control measures to reduce the spread of infection.