Prevalence, genetic characteristics, and antimicrobial resistance of Clostridioides difficile isolates from horses in Korea

• Published in: Anaerobe 2023-04, Vol.80, p.102700-102700, Article 102700
• Main Authors: Lee, Yu-Ran, Lee, Kichan, Byun, Jae-Won, Kim, Heejung, So, ByungJae, Ku, Bok-Kyung, Kim, Ha-Young, Moon, Bo-Youn
• Format: Article
• Language: English
• Subjects: Animals; Anti-Bacterial Agents - pharmacology; Bacterial Toxins - genetics; Clostridioides difficile; Clostridioides difficile - drug effects; Clostridioides difficile - genetics; Clostridium Infections - epidemiology; Clostridium Infections - microbiology; Clostridium Infections - veterinary; Drug Resistance, Bacterial - genetics; Enteric disease; Horses; Infection; Microbial Sensitivity Tests; Multidrug resistant; Multilocus sequence typing; Prevalence; Republic of Korea - epidemiology; Ribotyping
• ISSN: 1075-9964; 1095-8274
• DOI: 10.1016/j.anaerobe.2023.102700

Clostridioides difficile is an etiological agent of enteric diseases in humans and animals. Animals are considered a potential reservoir due to the genetic and antimicrobial resistance similarities between human and animal C. difficile isolates. In this study, we evaluated the genetic characteristics and antimicrobial resistance profiles of C. difficile isolated from 942 fecal samples collected from horses in South Korea during 2019–2020. The C. difficile isolates were tested for toxin genes including tcdA (A), tcdB (B), and cdtAB (CDT) and deletions of the tcdC gene by PCR. In addition, ribotyping, multilocus sequence typing, and antimicrobial susceptibility tests were performed. Twenty-three (2.4%) C. difficile isolates were associated with diarrhea in foals under 1 year old during the spring–summer period. Of these, 82.6% were toxigenic strains, determined to be A+B+CDT+ (52.1%) or A+B+CDT‒ (30.4%). All isolates were susceptible to metronidazole and vancomycin, and resistant to cefotaxime and gentamicin, and 76.2% were multidrug resistant (MDR). RT078/ST11/Clade 5 was the most common genotype (47.8%), which was also found in animals and humans worldwide. All RT078/ST11/Clade 5 strains were toxigenic and had deletions of the tcdC gene. About half of these strains were resistant to moxifloxacin, and 63.6% were MDR. C. difficile isolates in this study consisted mostly of toxigenic and MDR strains, and their genetic properties were highly similar to human C. difficile isolates. These results suggest high possibilities of zoonotic transmission and can provide knowledge for establishing strategies for the treatment and prevention of C. difficile infection. •C. difficile was associated with the diarrhea of foals in spring and summer in Korea.•RT078/ST11/Clade 5, a common genotype in horses, with A + B + CDT+ and deletion of the tcdC gene.•All non-toxigenic isolates were multidrug resistance.