Environmental and Nutritional Parameters Modulating Genetic Expression for Virulence Factors of Clostridioides difficile

Abstract

Clostridioides difficile infections (CDIs) continue to be a persistent healthcare concern despite newer antibiotic treatments, enhanced infection control practices, and preventive strategies focused on restoring the protective intestinal microbial barrier. Recent strides in gene sequencing research have identified many genes regulating diverse virulence factors for CDIs. These genes may be over- or under-expressed when triggered by various environmental and nutritional factors. The aims of this paper are to review the important genes involved in C. difficile pathogenesis and to identify modifiable environmental, nutritional, and other factors that may trigger the expression of these genes and thus offer new strategies to prevent CDIs.

Keywords: CDI; Clostridioides difficile; antibiotics; environmental factors; gene expression; probiotics; virulence.

Figure 1

Schematic models showing the major genes present in the pathogenicity locus regions for (A) Toxins A and B (PaLoc) and (B) binary toxin (CdtLoc) of Clostridioides difficile. Promoter proteins indicated by green arrows, regulatory genes indicated by red arrows, and toxin genes indicated by blue arrows. The agr1 operon located upstream of the PaLoc operon involves genes regulating quorum sensing. Abbreviations: PtoxA Promoter toxin A; PtoxB Promoter toxin B; QS, quorum sensing.