Pathogenomic insights and prevalence of the big six Enterohemorrhagic Escherichia coli from cattle and sheep

Enterohemorrhagic Escherichia coli (EHEC), particularly the O157:H7 serotype, poses significant public health risks with severe complications. Recent studies have identified six major non-O157 serotypes, collectively known as the 'big six', as substantial contributors to EHEC-related diseases. This study aimed to determine the prevalence of these six EHEC serotypes in cattle and sheep across six regions of T & uuml;rkiye and analyze the phenotypic and virulence gene characteristics of the isolates to assess their public health significance. A total of 4320 samples were collected from 720 sheep and 720 cattle during slaughter. From these samples, 5829 suspected EHEC colonies were isolated, with 182 confirmed as EHEC via polymerase chain reaction (PCR) analysis. The overall EHEC prevalence was approximately 4.2%, with isolates containing at least one stx gene. Serotyping identified two isolates (O121:H19 and O45:H2), both from bovine recto-anal mucosal swabs (RAMS) samples. Antibiotic susceptibility testing revealed that the O45 isolate was susceptible to most antibiotics but showed intermediate resistance to aztreonam and imipenem, while the O121 isolates exhibited multidrug resistance to ciprofloxacin, aztreonam, and gentamicin. Pulsed field gel electrophoresis (PFGE) and whole-genome sequencing (WGS) analyses indicated a high degree of genetic similarity between O121 isolates. These findings provide valuable insights into the genetic diversity, antibiotic resistance profiles, and prevalence of EHEC strains in T & uuml;rkiye. Accordingly, this study provides baseline data on the prevalence and genomic characteristics of EHEC in animal reservoirs in T & uuml;rkiye and represents an initial step toward establishing a comprehensive surveillance system.

Dergi

MICROBIAL PATHOGENESIS

Yıl

2026

Cilt

213

ISSN

0882-4010

eISSN

1096-1208

DOI

10.1016/j.micpath.2026.108391

WoS UID

WOS:001697273200001