Isolation and genotyping of Clostridium difficile from horses and cattle with diarrhe

Clostridioides difficile is a Gram-positive, spore-forming, and obligate anaerobic bacterium. Due to its spore form, it can survive under harsh environmental conditions for extended periods and may spread via fecal transmission. Initially considered a component of the human gastrointestinal microbiota, it was identified in 1978 as a toxin-producing pathogen and linked to antibiotic-associated diarrhea and pseudomembranous enterocolitis. In the following years, it became especially prominent in healthcare-associated diarrhea cases and was recognized as a significant gastrointestinal infectious agent. When the gut microbiota is disrupted by factors such as antibiotic use, advanced age, chemotherapeutic agents, or malnutrition, toxigenic strains can proliferate and cause disease through toxin production. The isolation of the bacterium not only from humans but also from farm animals, wildlife, environmental sources, and various food products, along with reported genotypic similarities between human- and animal-derived strains, highlights its zoonotic potential. This necessitates the evaluation of C. difficile within the One Health framework. The infection causes considerable burden on healthcare systems and livestock economies due to increased treatment costs, productivity losses, extended hospitalization, and workforce depletion. This study aimed to investigate the presence of Clostridioides difficile in horses and cattle with diarrhea in the Konya region. A total of 171 horse fecal samples were examined using the bacteriological culture method, and no positive findings were detected. Among these, 23 samples were tested by Toxin A/B ELISA, and two samples were found to be positive for Toxin A/B. From cattle, 116 samples were analyzed by bacteriological culture, 88 by RT-PCR, and 71 by Toxin A/B ELISA. PCR analysis revealed nine toxin-positive samples, all of which carried the toxin A (tcdA) gene. In one of these samples, the toxin B (tcdB) and binary toxin (cdtA/cdtB) genes were also detected. Toxin A/B ELISA analysis yielded 16 positive results, while no isolates were obtained by bacteriological culture. This regionally conducted study molecularly confirmed the presence of toxigenic C. difficile in calf samples. The findings suggest that this pathogen should be considered in the differential diagnosis of diarrheal cases. Moreover, the data obtained may contribute to future studies on C. difficile.