Etiological analysis on an outbreak of foodborne disease caused by Clostridium perfringens in Beijing, 2022

Objective  To povide a reference for rapid and accurate analysis of similar epidemics through pathogenic analysis of an outbreak of diarrhea caused by Clostridium perfringens in a school in Beijing.

Methods Multiplex real-time polymerase chain reaction (PCR) was used for screening of molecular pathogens. Based on the preliminary screening results, routine bacterial isolation and culture, biochemical identification and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry（MALDI-TOF MS) analysis were conducted. Virulence gene detection and pulsed field gel electrophoresis (PFGE) molecular typing were performed on the isolated C. perfringens.

Results Among the 28 anal swab samples, 26 samples were positive for C. perfringens in preliminary screening, and 26 strains were isolated. In 13 fecal samples, 10 samples were positive for C. perfringens in preliminary screening, and 20 strains were isolated from 4 samples. No pathogens were detected in other samples. The 46 strains of C. perfringens all carried cpa and cpe genes, which were C. perfringens type A with enterotoxin CPE gene. Among the 46 strains, 41 strains are concentrated in 2 PFGE bands.

Conclusion This diarrhea outbreak was caused by Clostridium perfringens (with enterotoxin), and molecular biological methods can be used for rapid detection of C. perfringens outbreaks.