Molecular Detection of Toxigenic Clostridioides difficile among Diarrheic Dogs and Cats: A Mounting Public Health Concern

Nowadays, pet animals are known to be asymptomatic carriers of Clostridioides difficile. This study was conducted to investigate the burden of toxigenic C. difficile among diarrheic dogs and cats using direct PCR on fecal samples to reveal better insights about the epidemiology of such toxigenic strains referring to its public health significance. For this purpose, fecal samples were obtained from 58 dogs and 42 cats experiencing diarrhea. Following DNA extraction, the extracted DNA was examined for the occurrence of C. difficile as well as toxigenic strains through the detection of C. difficile 16S rRNA and toxin encoding genes (tcdA, tcdB, cdtA and cdtB) using PCR. Moreover, partial DNA sequencing of toxigenic strains retrieved from dog and cat was carried out. Of 100 examined diarrheic animals, 90 (90%) were C. difficile positive, including 93.1% and 85.7% of dogs and cats, respectively. In addition, toxigenic strains were detected in 13 animals, giving an overall prevalence 13% with the following prevalence rates among dogs and cats 12.1% and 14.3%, respectively. Furthermore, the phylogenetic analysis of the obtained sequence revealed high genetic relatedness of tcdA sequence obtained from a cat to strains of human diarrheic cases to point out the public health threat of such sequence. In conclusion, the direct detection of toxigenic C. difficile using PCR among dogs and cats highlights the potential role of household pets as a source for such strains to human contacts.