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

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

Methods: 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.

Results: 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.

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