Determination of Molecular Characteristics in Clostridium difficile Isolated from Cattle and Human, in Tehran, IR Iran

Background and Objectives: Clostridium difficile is a gram-positive, anaerobic, spore-forming bacterium, catalase negative and is one of the most significant causes of antimicrobial-associated nosocomial diarrhea in humans and diseases in livestock. The aim of this study was to isolate Clostridium difficile from cattle and human’s feces and identify molecular characteristics of C. difficile in human and cattle. Materials and methods: 95 fecal samples in cattle and human were isolated from farms and clinics in Tehran respectively in order to determine their molecular characteristics. Clostridium difficile was isolated by microbial culture techniques and in the following stage, genomes of bacteria were isolated by the DNA extraction kit then tcdA, tcdB, cdtA and cdtB were identified by multiplex PCR method and in the final stage PFGE analysis was used in order to determine the ribotypes. Results:A total of 95 samples were collected from various sources and C. difficile was isolated from 8 (14.03%) of 57 cattle, 4 (10.52%) of 38 humans. Out of those isolates 1 and 2 isolates from human and cattle, respectively were toxigenic. The toxigenic isolates carried both tcdA, and tcdB (A+B+) and the human isolate was also positive for binary toxin genes (cdtA and cdtB). Human A+B+ isolates belonged to (ACD 019) and the ribotypes of cattle isolate were (014 and ACD 010). PFGE analysis could not distinguish similar ribotypes/toxin types of toxigenic isolates. Both the toxigenic isolates had cytopathic effect on Vero and HeLa cell monolayers at 1:100 dilutions of cell-free culture supernatants duration the time of inoculation. Conclusion: According to the results, the overall prevalence of clostridium difficile with toxigenic genes in human was around 2.63% and in cattle accounted for 3.50%. Although this amount seems negligible, this bacterium is one of the main reasons for calves’ death, so it can cause financial damage in agricultural industry. Furthermore, as this bacterium has detrimental effects, health care system will be forced to pay more costs, so control and prevention measures should be taken into consideration.