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

Supapit Wongkuna; Tavan Janvilisri; Matthew Phanchana; Phurt Harnvoravongchai; Amornrat Aroonnual; Sathid Aimjongjun; Natamon Malaisri; Surang Chankhamhaengdecha

doi:10.3390/antibiotics10060714

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

Antibiotics (Basel). 2021 Jun 13;10(6):714. doi: 10.3390/antibiotics10060714.

Authors

Supapit Wongkuna¹, Tavan Janvilisri¹, Matthew Phanchana², Phurt Harnvoravongchai³, Amornrat Aroonnual⁴, Sathid Aimjongjun⁵, Natamon Malaisri³, Surang Chankhamhaengdecha³

Affiliations

¹ Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.
² Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand.
³ Department of Biology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.
⁴ Department of Tropical Nutrition and Food Science, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand.
⁵ Graduate Program in Molecular Medicine, Faculty of Science, Mahidol University, Bangkok 10400, 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.

Keywords: C. difficile infection; antibiotic resistance; molecular analysis; toxin production.

Abstract

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