Emerging <i>Clostridioides difficile</i> strains belonging to PCR ribotype 955 in Serbia are distinct from metronidazole-resistant RT955 outbreak isolates from the UK

End 2023, the UK Health Security Agency sent an alert about a new hypervirulent <i>Clostridioides difficile</i> PCR ribotype, ribotype 955 (RT955), causing slowly progressing infection clusters in hospitals in the Midlands. Between March 2018 and February 2022, surveillance of <i>Clostridioides difficile</i> infections (CDI) was performed in southern Serbia with centres providing medical services for approximately 750,000 inhabitants. Using the ECDC recommended protocol, clinical, epidemiological and microbiological data were collected. <i>C. difficile</i> RT955 was identified in 27 (7%) of 383 surveyed patients with CDI. Of 27 patients, 16 (59%) was older than 60 years and 19 (70%) were male. CDI was always associated with previous antibiotic therapy and had a hospital onset in 23 (85%) patients. The clinical presentation was milder than reported in UK. All sequenced strains belonged to multilocus sequence type (ST) 1 and were highly similar, with 0–1 alleles differences in a core genome multilocus sequence typing analysis. The strains differed clearly from the UK RT955 outbreak strain by whole genome sequencing and phenotypic susceptibility to metronidazole, lincosamides and rifampicin. Interestingly, a high-level erythromycin resistance was observed associated with the presence of the <i>mrmA</i> gene. Both the UK and Serbian RT955 strains contained <i>gyrA</i>_p.T82I associated with resistance to fluoroquinolone antimicrobials and carried the PnimBG promoter mutation, suggestive for haem-dependent metronidazole resistance. We conclude that <i>C. difficile</i> RT955 is present in southern Serbia since 2018. The Serbian RT955 strains differed clearly from a representative UK cluster strain.