RESTRICTIONMAPPING OF TOXIN A GENE FRAGMENT IN CLOSTRIDIUMDIFFICILE

Toxin A variant strain was identified by restriction endonuclease analysis (REA) as type CF2, was not detected by an immunoassay for C. difficile toxin A. Culture supernatants of CF2 failed to elicit significant enterotoxic activity in the rabbit ileal loop assay but did produce a typical cytopathic effects in cell culture assay. Southern hybridization, PCR amplification, and DNA sequence analysis were performed on the toxin A (tcdA) and toxin B (tcdB) genes of type CF2 isolate. According to these facts we had tried to obtain new restriction map for the fragment of these genes by PCR and (restriction fragment length polymorphisms) - RFLPs methods using various restriction enzymes such as Hind III, pstI and Eco RI. In this work various fragments had been identified with 250-700bp lengths. Restriction map of fragment 250bp was preformed. The results showed a new restriction map by which obtained a new variation at the same fragment.