# Prevalence, Phylogenetic Distribution, Antimicrobial Resistance, and Genetic Relatedness of Extraintestinal Pathogenic E. coli (ExPEC) Strains Isolated from Beef Cattle and Slaughterhouse Environment

## TL;DR

This study found antibiotic-resistant ExPEC bacteria in cattle and slaughterhouse environments in Turkey, highlighting risks to public health and the need for monitoring.

## Contribution

The study identifies ExPEC in slaughterhouse workers' hands and diverse yet related strains across sources, emphasizing cross-contamination risks.

## Key findings

- ExPEC was detected in 8.8% of samples, with the highest contamination rate on workers' hands (25%).
- Most ExPEC isolates belonged to phylogroups B2 and D, commonly linked to human infections.
- High resistance to ampicillin and ciprofloxacin was observed, raising public health concerns.

## Abstract

This study examined the presence, genetic characteristics, and antibiotic resistance of extraintestinal pathogenic Escherichia coli (ExPEC) in cattle and slaughterhouse environments in southeastern Turkey. ExPEC was detected in 8% of samples, including carcasses, hides, rectal swabs, and particularly workers’ hands (25%), indicating multiple potential points of cross-contamination. The isolates harbored key virulence genes such as iutA, papA and papC, and most belonged to phylogenetic groups B2 and D, which are commonly associated with human infections. High levels of antibiotic resistance were observed, especially against ampicillin and ciprofloxacin, raising significant public health concerns. Genetic analyses revealed diverse yet closely related strains across different sources, further supporting evidence of cross-contamination within the slaughterhouse. Overall, the findings suggest that cattle and slaughterhouse environments may act as reservoirs for antibiotic-resistant ExPEC, underscoring the importance of continuous monitoring and control strategies within a One Health framework.

Escherichia coli is a commensal bacterium found in the gastrointestinal tracts of animals, and they might serve as a vehicle for transmitting extraintestinal pathogenic Escherichia coli (ExPEC) to the environment and human. This study aimed to investigate the prevalence, phylogenetic distribution, antimicrobial resistance, and genetic relatedness of ExPEC in beef cattle, slaughterhouse environment, and workers involved in the evisceration process during slaughter. A total of 447 samples were collected from two slaughterhouses located in the Diyarbakir and Batman cities of the Southeast Anatolia Region of Turkiye. The samples included swabs from beef carcasses (n = 133), rectal samples (n = 133), hides (n = 133), knives (n = 18), holding pens (n = 12), water (n = 6), and workers’ hands (n = 12). The samples were analyzed for the presence of ExPEC, and then isolates were screened for antimicrobial susceptibility, phylogenetic groups, and genetic relatedness. A total of 36 out of 447 samples were confirmed to be ExPEC-positive, yielding a prevalence rate of 8.80%. The contamination rates for carcasses, hides, rectal, knives, holding pens, water, and workers’ hands were 10.5%, 6.06%, 6.5%, 5.5%, 8.3%, 0%, and 25%, respectively. The ExPEC isolates were classified into phylogroups D (38.8%), B1 (25.0%), B2 (25.0%), and A (5.5%). Of the isolates, 55.55% (20/36) exhibited resistance to at least one antimicrobial agent from three or more, with the highest resistance observed against ampicillin (61.1%). ERIC-PCR analysis revealed that 35 of the isolates formed 19 distinct clusters, indicating a high level of genetic diversity among the ExPEC isolates. The results of this study demonstrate that beef cattle, the slaughterhouse environment, and workers’ hands can serve as sources of ExPEC contamination.