A longitudinal analysis of Clostridioides difficile virulence profiles across three geographic regions in Israel...

Clostridioides difficile infection (CDI) is one of the leading infectious diarrhea worldwide. C. difficile pathogenicity is mediated by various virulence factors, including toxins and biofilm formation. This study included 313 C. difficile isolates that were previously collected from four medical centers. We aimed to investigate the prevalence, distribution, and associations of virulence factors in C. difficile strains from both healthcare-associated (HA)- and community-acquired (CA)-CDI patients across Israel from 2020 to 2022.

Multi-locus sequence typing (MLST) and whole-genome sequencing (WGS) were performed for strain classification and virulence gene detection. Toxin and biofilm production were also characterized.

Sequence type (ST) 42 (12.5%) and ST2 (11.5%) were the most prevalent strains. Toxin production patterns were significantly associated with setting of infection acquisition (p < 0.0001). Isolates producing both toxin A and B were 2.5-fold more common among HA-CDI strains, while toxin-A-producers were more frequent in CA-CDI. Biofilm was produced by 96.9% of isolates, with strong biofilm-producing strains significantly more prevalent in hospitals (p < 0.001). Furthermore, isolates producing both toxins A and B were predominantly moderate or strong biofilm producers (p < 0.0001). agrD presence was significantly associated with ST, toxin production patterns and biofilm-production capacity (p < 0.0001 for ST and biofilm, p = 0.0016 for toxins).

This study revealed a high diversity of C. difficile strains in Israel and demonstrated that virulence factor patterns differ significantly across STs and the acquisition setting. The differences between HA-CDI and CA-CDI isolates in some virulence factors underscores the importance of continuous epidemiological surveillance to guide tailored treatment and prevention strategies.