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Background: Several studies have highlighted the incidence of Clostridioides difficile infections (CDIs) in Taiwan and certain ribotypes have been related to severe clinical diseases. A study was conducted to investigate the polymerase chain reaction (PCR) ribotypes and genetic relatedness of clinical C. difficile strains collected from January 2009 to December 2015 at a hospital in northeastern Taiwan. Material and methods: A modified two-step typing algorithm for C. difficile was used by combining a modified 8-plex and 3′-truncated tcdA screening PCR. In addition, MLVA typing was adopted for investigation of bacterial clonality and transmission. Results: Among a total of 86 strains, 24 (28%) were nontoxigenic and 62 (72%) had both tcdA and tcdB (A + B+). No tcdA-negative and tcdB-positive (A−B+) strains were identified. Binary toxin (CDT)-producing (cdtA+/cdtB+) strains were started to be identified in 2013. The 21 (34%) A+B+ clinical strains with binary toxin and tcdC deletion were identified as RT127 strains, which contained both RT078-lineage markers and fluoroquinolone (FQ)-resistant mutations (Thr82Ile in gyrA). Multiple loci variable-number tandem repeat analysis (MLVA) for phylogenetic relatedness of RT127 strains indicated that 20 of 21 strains belonged to a clonal complex that was identical to a clinical strain collected from southern Taiwan in 2011, suggestive of a clonal expansion in Taiwan. Conclusion: A two-step typing method could rapidly confirm species identification and define the toxin gene profile of C. difficile isolates. The clonal expansion of RT127 strains in Taiwan indicates monitoring and surveillance of toxigenic C. difficile isolates from human, animal, and environment are critical to develop One Health prevention strategies.

Background: Several studies have highlighted the incidence of Clostridioides difficile infections (CDIs) in Taiwan and certain ribotypes have been related to severe clinical diseases. A study was conducted to investigate the polymerase chain reaction (PCR) ribotypes and genetic relatedness of clinical C. difficile strains collected from January 2009 to December 2015 at a hospital in northeastern Taiwan., Material and Methods: A modified two-step typing algorithm for C. difficile was used by combining a modified 8-plex and 3'-truncated tcdA screening PCR. In addition, MLVA typing was adopted for investigation of bacterial clonality and transmission., Results: Among a total of 86 strains, 24 (28%) were nontoxigenic and 62 (72%) had both tcdA and tcdB (A + B+). No tcdA-negative and tcdB-positive (A - B + ) strains were identified. Binary toxin (CDT)-producing (cdtA+/cdtB+) strains were started to be identified in 2013. The 21 (34%) A + B + clinical strains with binary toxin and tcdC deletion were identified as RT127 strains, which contained both RT078-lineage markers and fluoroquinolone (FQ)-resistant mutations (Thr82Ile in gyrA). Multiple loci variable-number tandem repeat analysis (MLVA) for phylogenetic relatedness of RT127 strains indicated that 20 of 21 strains belonged to a clonal complex that was identical to a clinical strain collected from southern Taiwan in 2011, suggestive of a clonal expansion in Taiwan., Conclusion: A two-step typing method could rapidly confirm species identification and define the toxin gene profile of C. difficile isolates. The clonal expansion of RT127 strains in Taiwan indicates monitoring and surveillance of toxigenic C. difficile isolates from human, animal, and environment are critical to develop One Health prevention strategies., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest in this work., (Copyright © 2022. Published by Elsevier B.V.)

Objectives: The information of antimicrobial susceptibility, toxin gene, and ribotype distribution of toxigenic Clostridium difficile isolates in Taiwan remain limited., Patients and Methods: The study was conducted from January 2015 to December 2016 in 5 hospitals in Taiwan. Adults aged ≥20 years with a hospital stay for >5 days were included, and those with colectomy or intestinal infection due to other enteropathogens were excluded. Multiplex PCR was used to detect tcdA, tcdB, cdtA, cdtB , and tcdC deletions, and antimicrobial susceptibility for metronidazole, vancomycin, doxycycline, and tigecycline was investigated. Ribotypes of those isolates with tcdC deletion and tcdA+/tcdB+ were determined., Results: Of 1112 C. difficile isolates collected from adults at 5 hospitals, 842 were toxigenic, including 749 (89.0%) tcdA+/tcdB+ isolates and 93 (11.0%) tcdA-/tcdB+ . Of the toxigenic isolates, 76 (9.0%) had a tcdC deletion and were cdtA+/cdtB+ , indicative of hypervirulence, and RT078 lineage, including RT126, RT127, and RT078, predominated (n=53, 76.3%). Similar to the susceptibility data in Asia countries, metronidazole or vancomycin resistance was rare, noted in 1.2% or 2.1%, respectively. Reduced doxycycline susceptibility (minimum inhibitory concentration [MIC] of ≥8 mg/L) was more common among RT078 lineage than non-RT078 lineage (75.9%, 44/58 vs 6.0%, 47/784; P <0.001). Also reduced tigecycline susceptibility (MIC ≥0.125 mg/L) was more common among RT078 lineage (20.7%, 12/58 vs 6.5%, 51/784; P <0.001)., Conclusion: In Taiwan, toxigenic C. difficile isolates remain susceptible to metronidazole and vancomycin. RT078 lineage predominated among toxigenic isolates with cdtA, cdtB , and tcdC deletion, and more often had reduced doxycycline and tigecycline susceptibility than the isolates other than RT078 lineage., Competing Interests: Disclosure The authors report no conflicts of interest in this work.