Abstract:ObjectiveTo study gene transcriptions of pathogenicity locus (PaLoc) and toxin B expressions of A-B+ Clostridium difficile （C. difficile）strain BJ08 isolated in China and strain US1 isolated in C. difficile infection outbreak regions in the United States, and provide theoretical support for prevention and control of possible outbreak of C. difficile infection in China.MethodsCells and supernatants of C. difficile were collected every 3 hours, gene expressions of PaLoc domain, including tcdA, tcdB, tcdC, tcdR and tcdE genes, were detected by realtime polymerase chain reaction (PCR), the expressions of toxin B in cells and supernatants were detected by enzymelinked immunosorbent assay (ELISA).ResultsThe growth rate of strain US1 was slightly faster than that of BJ08, and the degradation rate of US1 was significantly faster than that of BJ08（P＜0.05）; No toxin A was detected but mRNA of tcdA were detected in both BJ08 and US1, and there was no significant difference in tcdA expression between BJ08 and US1. The transcriptions of tcdB,tcdC and tcdE of BJ08 were 3 hours earlier than those of US1. There was no significant difference in the production of toxin B in supernatants and cells between strain BJ08 and US1.ConclusionCompared with US1, there is similar virulence or stronger gene regulation of BJ08, possible outbreak of C.difficile infection in China should be alerted.