Temporal Variations in Patterns of Clostridioides difficile Strain Diversity and Antibiotic Resistance in Thailand

Abstract

Clostridioides difficile has been recognized as a life-threatening pathogen that causes enteric diseases, including antibiotic-associated diarrhea and pseudomembranous colitis. The severity of C. difficile infection (CDI) correlates with toxin production and antibiotic resistance of C. difficile. In Thailand, the data addressing ribotypes, toxigenic, and antimicrobial susceptibility profiles of this pathogen are scarce and some of these data sets are limited. In this study, two groups of C. difficile isolates in Thailand, including 50 isolates collected from 2006 to 2009 (THA group) and 26 isolates collected from 2010 to 2012 (THB group), were compared for toxin genes and ribotyping profiles. The production of toxins A and B were determined on the basis of toxin gene profiles. In addition, minimum inhibitory concentration of eight antibiotics were examined for all 76 C. difficile isolates. The isolates of the THA group were categorized into 27 A−B+CDT− (54%) and 23 A-B-CDT- (46%), while the THB isolates were classified into five toxigenic profiles, including six A+B+CDT+ (23%), two A+B+CDT− (8%), five A−B+CDT+ (19%), seven A−B+CDT− (27%), and six A−B−CDT− (23%). By visually comparing them to the references, only five ribotypes were identified among THA isolates, while 15 ribotypes were identified within THB isolates. Ribotype 017 was the most common in both groups. Interestingly, 18 unknown ribotyping patterns were identified. Among eight tcdA-positive isolates, three isolates showed significantly greater levels of toxin A than the reference strain. The levels of toxin B in 3 of 47 tcdB-positive isolates were significantly higher than that of the reference strain. Based on the antimicrobial susceptibility test, metronidazole showed potent efficiency against most isolates in both groups. However, high MIC values of cefoxitin (MICs 256 μg/mL) and chloramphenicol (MICs ≥ 64 μg/mL) were observed with most of the isolates. The other five antibiotics exhibited diverse MIC values among two groups of isolates. This work provides evidence of temporal changes in both C. difficile strains and patterns of antimicrobial resistance in Thailand.

Introduction to the Special Issue on Clostridioides difficile

“…Interestingly, as ribotype 017 was the most common in both groups, 18 ribotyping patterns previously unknown were identified in the region. This work provides evidence of temporal changes in CD strains in Thailand [10].…”

“…The report by Wongkuna et al showed data addressing ribotypes, toxigenicity, and antimicrobial susceptibility profiles of two series of CD isolates in Thailand [10]. The authors compared two series of CD isolates, including 50 isolates collected from 2006 to 2009 and 26 isolates collected from 2010 to 2012.…”

Genomic Epidemiology and Antimicrobial Resistance Profiles of Clostridioides difficile from Multi-Hospitals in a City in Eastern China

“…In addition, environmental samples were not collected at the same time during the study. Moreover, because C. difficile forms spores, which lead to repeated infection, and the persistence of spores in the environment promotes their transmission, 46 we cannot evaluate these potential transmission sources. Fidaxomicin is associated with improved sustained clinical cure and significantly reduces CDI recurrence compared with vancomycin and recommended by several guidelines.…”