Unveiling the impact of antibiotic stress on biofilm formation and expression of toxin-antitoxin system genes in Clostridium difficile clinical isolates

The study investigates how antibiotics affect biofilm formation and toxin gene expression in Clostridium difficile, which is essential for its survival and persistence.

The study confirmed 25 strains of C. difficile and assessed biofilm formation. The MIC of metronidazole and vancomycin was determined through agar dilution, and the impact of sub-MIC levels on biofilm formation and eradication was investigated. Additionally, Real-time PCR was used to analyze the expression levels of target genes related to antibiotic treatment.

We found that certain genes, such as the ImmA/IrrE system, were associated with increased biofilm formation in isolates. Sub-MIC antibiotic levels influenced gene expression related to biofilm activities, particularly emphasizing the importance of toxin-antitoxin systems. The results suggest that antibiotics at sub-MIC levels may play a signaling role in promoting biofilm formation and gene expression in C. difficile.

Our study suggests that toxin and antitoxin genes may impact C. difficile biofilm formation, while antibiotics could signal biofilm strengthening and gene expression increase.