Characterization of Clostridioides difficile strains, the disease severity and the microbial changes they induce

Abstract Background In recent years, the global incidence of Clostridioides difficile infection has increased dramatically, with the emergence of hyper-virulent strains. The characteristics of the different strains, the severity of the disease they cause, their susceptibility to antimicrobial agents, and the changes they inflict on the gut microbiome, have not yet been comprehensively studied. Results Using Multilocus Sequencing Typing (MLST) analysis, the different sequence types (STs) of 70 clinical isolates were determined. The most frequent strains were ST04 (22.5%), ST37 (12.7%), ST104 (8.5%), ST42 (7%), and ST02 (7%). The different STs were divided to different phylogenetic lineages (clades), with clade 1 forming the majority of cases (81.4%, 57/70). A significant correlation was found between ST and age (p = 0.024); patients with ST104 (n = 6) were of the lowest mean age (61.67 ± 18.8 years), while patients with ST37 (n = 9) were of the oldest mean age (79.67 ± 10.6 years). In addition, a significant correlation between ST and susceptibility to moxifloxacin was identified (p = 0.001); 15 ST04 isolates (93.7%, n = 16) were resistant, while all ST42 (n = 5) and ST104 isolates (n = 6) were sensitive. Significant correlations were found between clade and binary toxin gene presence (p = 0.002), with 93% of the isolates belonging to clade 1 lacking the gene. Furthermore, significant correlations were found between clade and susceptibility to both metronidazole and vancomycin (p = 0.024, p = 0.035, respectively). Differences in intestinal microbiome were affected by age, clade distribution and ST. Conclusions By defining the characteristics of the different strains and clades, clinicians can choose medical interventions based on the predicted response or disease severity associated with each strain, enabling new advances in the field of personalized medicine.