Clostridioides difficile PCR ribotype (RT) 002 is the second most prevalent RT in the Netherlands. In 2019, an increase in Clostridioides difficile infections (CDIs) due to clonal RT002 strains was reported in Ireland. In retrospect, a significant increase in the proportion of CDI due to RT002 was detected in the Netherlands between May 2017 and May 2018 (11.9% of 683 cases vs 6.5% of 865 in the previous year). Our aim was to analyze and characterize CDI due to RT002 over time and to assess whether RT002 isolates in the Netherlands were related to the Irish RT002 isolates.During the period from May 2009 to April 2021, Dutch patients with CDI due to RT002 showed less severe CDI (22%) in comparison with hypervirulent RTs (RT027, 29%, and RT078, 25%), similar to grouped data from other non-hypervirulent ribotypes (21%). However, RT002-associated CDI prior to the increased proportion (2009-2017) showed CDI severity similar to CDI associated with hypervirulent types, whereas this was no longer the case after the increase (2017-2021). Using core genome multi-locus sequence typing (cgMLST), Dutch isolates were found not to be related to the Irish outbreak strain. Several Dutch strains clustered together without an evident epidemiological link, suggesting recent emergence. We conclude that the increase of RT002 in Ireland and the Netherlands does not represent clonal spread but is more likely associated with clinical, epidemiological, or treatment changes.IMPORTANCEClostridioides difficile is a significant cause of hospital-associated infections, making it relevant to understand the emergence and spread of different ribotypes. This study highlights a rise in cases of PCR RT002 in the Netherlands, suggesting changes in its prevalence. Despite the increase in RT002 infections, the severity of disease appears to have decreased and is lower compared to more virulent ribotypes. Further research is needed to understand the factors driving this change. Additionally, this study underscores some limitations of cgMLST. cgMLST is valuable for identifying genetic relationships. However, it cannot always distinguish between widespread, recently emerged strains and local transmission chains, making it challenging to determine the exact sources of infection. Continued surveillance and genetic characterization of C. difficile are essential to better understand these trends and improve control measures.
Baktash et al. (Tue,) studied this question.