Detection Of Clostridium Difficile TcdA And TcdB And The Binary Toxin (cdtA/cdtB) Genes By The Multiplex PCR Method

Objective:To Study on multiplex PCR method for the detection of Clostridium difficile toxin genes tcdA, tcd B, cdtA and cdtB. TO detect the gene types of toxin of Clostridium difficile isolated from the patientsMethods:Selected the patients with diarrhea according to the standard of American Clinical Practice Guidelines for Clostridium difficile Infection in Adults.160 stools of hospitalized patients with diarrhea were collected in Peking Union Medical College Hospital from June 2013 to May 2014. C. difficile was isolated from selective medium CCFA by using standard method of bacterial culture of C. Difficile, and thus the strains were identified by VITEK-MS mass spectrometry. Toxin A or toxin B in stool samples of patients were detected by enzyme-linked fluorescent assay (ELFA), and its characteristics were analyzed. Multiplex PCR method was used to detect toxin genes tcdA, tcd B, cdtA and cdtB of C. difficile.Results:In 160 cases of patients with diarrhea, C. difficile toxin A/B was found in 33 stool specimens in which 28 strains of C. difficile were isolated. There were 9 strains of C. difficile in 127 stool specimens of which C. difficile toxin A/B was negative. A total of 37 strains of C. difficile were isolated from stools. The rate of detection of toxin was 75.68%(28/37) in application of immunological detection. Toxin gene A/B was positive in 36 strains of Clostridium difficile amount of 37 strains by using the multiple PCR method, and the rate of detection was 97.3%(36/37). PCR revealed two different toxin gene profiles:35 tcdA+, tcdB+, cdtA-/cdtB-; one tcdA+, tcdB+, cdtA+/cdtB+.Conclusions:Most strains isolated from the patients produced toxin; The multiplex PCR method offers a one-step, rapid screening method for targeting the toxin genes tcdA, tcdB, cdtA and cdtB. The main toxin gene type contains tcdA+, tcdB+, cdtA-/cdtB-, none of which were tcdA-, tcdB+.