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.

For precise property control of sintered products, it is important to understand accurately the packing density of the powder. We developed a packing simulation program that could make a packed bed of spherical particles having particle size distribution. In addition, the influence of the particle shape of the actual powder on the packing density was quantitatively analyzed. The predicted packing densities corresponded well to the actual data.