Isolation of Shiga toxin-producing Escherichia coli from sheep faecal samples: bacteriological findings

Shiga toxin-producing Escherichia coli (STEC) poses a significant public health risk due to its zoonotic potential and association with foodborne outbreaks. This study investigates the presence of STEC in faecal samples collected from sheep, focusing on bacteriological methods for isolation and preliminary characterization. Growth on selective agar showed that 90 of 140 faecal samples were positive for STEC. The total average prevalence was 64.3% (95% CI 56.1-71.7%). The highest prevalence was 71.4% (54.9-83.7%), recorded in summertime, while the lowest was 51.4% (35.6-67%) in the autumn. Selected isolates were found to be resistant to commonly used antibiotics, with isolates expressing a resistant phenotype to two, three or more of the tested antibiotics. Based on the Biocheck.UGent system for risk-based assessment of farm biosecurity, the total, internal and exterior average farm biosecurity scores were substantially lower than the world average.