Prevalence and molecular types of Clostridium difficile isolates from faecal specimens of patients in a tertiary care centre.

Clostridium difficile infection (CDI) leads to considerable morbidity and mortality among hospitalized patients. Faecal specimens from 1110 hospitalized patients suspected for CDI were cultured for isolation of C. difficile and characterization of virulence genes. PCR was carried out for toxigenic genes tcdA, tcdB, cdtA and cdtB and PCR-RFLP for fliC and slpA genes. Of 174 (15.7%) C. difficile isolates, 121 (69.5%) were toxigenic, amongst which 68 (56.2%) also had both tcdA and tcdB genes. The remaining 53 (43.8%) of the isolates also had at least one of the toxin genes. Binary toxin genes (cdtA and cdtB) with only one of the two components were present in 16 (9.2%) of the 174 isolates. The other virulence genes - fliC and slpA - were present in 100% of the isolates. The most frequent PCR-RFLP type of fliC gene was type I (n = 101), followed by type VII (n = 49) and type III (n = 24). The slpA gene presented with three combinations of patterns. Characterization of virulence genes in C. difficile isolates is of extreme importance for epidemiological surveillance and control of outbreaks owing to the capacity of this bacterium to adapt to new environmental circumstances, leading to the emergence of new epidemic strains.