Crowded pet shops can become infected with various pathogens. Although dog carriers of Clostridioides difficile tend to be asymptomatic, the toxigenic strains sometimes cause gastrointestinal symptoms in humans. The present study was conducted to determine the infection rate of C. difficile in pet shops. The feces of 137 dogs younger than one year of age, collected from four pet shops, were assessed by culture and PCR. Carriage rates of C. difficile in dogs aged ≤90, 91-180, and ≥181 day-old were 12.2% (10/82, 95% confidence interval: 6.0-21.3%), 0.0% (0/42, 95% confidence interval: 0.0-8.4%), and 7.7% (1/13, 95% confidence interval: 0.2-36.0%), respectively. Five C. difficile isolates carried genes encoding toxins A and B, while the remaining isolates contained only toxin B. However, none of the C. difficile carriers had diarrhea. These results highlight the necessity of promoting adequate hygiene precautions in pet shops to prevent infection by C. difficile.

This study sought to confirm the inhibitory ability of Clostridioides difficile KCTC 5009 strain using the bacteriocin-producing Lactococcus lactis CJNU 3001 strain. For this purpose, bacterial culture and partially purified bacteriocin verified the antibacterial activity against C. difficile strain. As a result, both samples showed strong antibacterial activity against the target strain. Co-culture tests were performed to more closely analyze the competition between the two strains. As a result, a similar inhibitory effect was confirmed in RCM broth and CMM (colon model medium) broth. In particular, inhibition of C. difficile KCTC 5009 strain was not observed until the exponential phase of the growth of L. lactis CJNU 3001 strain, because bacteriocins were produced during that period. It was inferred that it actively suppressed the growth of the target strain after that. Therefore, as it was proven that the bacteriocin-producing L. lactis CJNU 3001 strain can effectively control C. difficile strain in co-cultures, it was judged that it could be an alternative for CDI (Clostridioides difficile infection) treatment.