Comparative Genomic Diversity of Clostridium Difficile during Sequential Recurrences of Infections: A Review

Clostridium difficile is an important emerging infectious agent, and might colonize in digestive tract of animals and humans. C. difficile exhibits a low level of gene conservation. Consequently, antibiotic therapy has demonstrated in 15-30% effectiveness of the cases. In the current review we summarized up to date information about the drug resistance genotypes of C. difficile for the first time, including sporulation and motility methods, growth suitability, antibiotic susceptibility, and whole-genome sequencing. PCR enables to certify the recurrences were a mixture of original (relapse) and new strains (reinfection). Our study revealed that there was a steady difference among various genotypes, demonstrating that mutations in the DNA genes were common in the antibiotic resistance phenotypes. Together our data revealed that antibiotic resistance poses selective pressure on the genome evolution of C. difficile that could lead to more adoptable strains with drug resistance. This study may open a new avenue for the research in understanding the mechanism of C. difficile adaptation to antibiotics and development of new antibacterial drugs. However, further research is needed to explore C. difficile genomic diversity changed from molecular typing assays to total-genome sequence comparisons, and comparative genome microarrays.