Pathogen characterization of a Clostridium perfringens associated foodborne disease outbreak

ObjectiveTo determine the molecular characteristics of the outbreak associated Clostridium perfringens， and to contribute to improved future outbreak management.MethodsReal-time fluorescence polymerase chain reaction （RT-PCR） was used for rapid screening of samples. Conventional bacterial isolation was performed on RT-PCR positive samples， and mass spectrometry analysis， and biochemical identification were conducted for identification. Virulence genes detection， antimicrobial susceptibility testing were conducted on confirmed C. perfringens isolates. Molecular typing was carried out using pulsed field gel electrophoresis （PFGE）.ResultsC. perfringens was detected in 10 rectal swabs and 1 food sample （barbecued meat）. All 11 C. perfringens were positive for virulence gene detection， with 9 isolates being cpa+/cpe+ and 2 being cpa+/cpe-. PFGE-based cluster analysis identified two PFGE patterns. One isolate from the barbecued meat and eight from the rectal swabs belonged to the same pattern which were identical， while two other isolates from another pattern showed a similarity of 94.7%. While all isolates were sensitive against piperacillin， ceftriaxone， imipenem， penicillin， clindamycin， and chloramphenicol， three isolates demonstrated resistance against metronidazole.ConclusionBased on clinical symptoms， epidemiological investigation， and laboratory testing， it is suggested that this foodborne disease outbreak was caused by Clostridium perfringens. Enhanced surveillance of Clostridium perfringens is needed to monitor the emergence and dissemination of antimicrobial resistance in this species.