Etiology analysis and source tracing of a foodborne disease outbreak caused by Campylobacter jejuni

Abstract

ObjectiveTo conduct the pathogenic bacteria detection， the carriage of virulence genes and the source tracing analysis in a foodborne disease outbreak event.MethodsThe samples collected from the event were rapid screened by FilmArray multiplex polymerase chain reacion（PCR） system， and were conducted to bacteria culture， isolation and identification simultaneously. Real-time PCR was performed for virulence genes of isolated strains. Homologous analysis of the strains was studied using 16S rRNA gene sequence analysis and pulsed field gel electrophoresis（PFGE） molecular genotyping.ResultsCampylobacter jejuni strains were detected from anal swabs of 2 patients and 4 canteen workers. All of the 6 Campylobacter jejuni strains carried flaA， cadF， imaA， cdtA， cdtB and cdtC virulence genes. All the strains were closely associated with Campylobacter jejuni via 16S rRNA gene sequence analysis， but the phylogenetic distance between one strain and the other 5 strains was slightly further. The results of PFGE showed that 6 strains of Campylobacter jejuni could be divided into 3 PFGE patterns， 3 strains and other 2 strains belonged to the same PFGE pattern respectively， with similarity of 52.2%. The rest belonged to a different PFGE pattern， with similarity of 26.7% compared to others.ConclusionLaboratory analysis indicated that different clones of Campylobacter jejuni infection was the cause of this foodborne disease outbreak.

Keywords

• campylobacter jejuni
• 16s rrna gene sequence analysis
• pfge
• virulence gene