Campylobacter spp. isolation,its toxin genes detection and molecular subtyping in diarrhea patients in Shanghai in 2014

Objective To investigate the status quo of Campylobacter spp. infection in Shanghai and study its molecular characteristics and virulence and toxin genes. Methods Stool samples collected from diarrheal patients were cultured for bacterial pathogens using membrane filter method. The strains were identified by biochemical tests and PCR. PCR was applied to detect six virulence and toxin genes including flaA,cdtA,cdtB,cdtC,virB11,cadF. Pulsed-field gel electrophoresis (PFGE) was carried out for subtyping. Results A total of 43 Campylobacter spp. (1.9%) were collected from 2 235 stool samples in Shanghai in 2014 including 41 Campylobacter jejuni isolates(95.3%) and 2 Campylobacter coli isolates(4.7%). The data showed 100.0% (43/43) of the isolates were positive for flaA and cadF, and 93.0% (40/43) of the isolates positive for cdtA and cdtB. And 88.4% (38/43) of the isolates were positive for cdtC. Only 7.0% (3/43) of the isolates were positive for virB11. Using PFGE, 43 Campylobacter jejuni and Campylobacter coli strains were subtyped into 6 clusters. Conclusion The genes of flaA and cadF are ubiquitous on Campylobacter spp. isolates. The distribution of cdt gene cluster in Campylobacter spp. is high, while that of virB11 is low. The PFGE types of Campylobacter spp. isolated in Shanghai are of diversified and complicated features, which causes mainly sporatic diarrhea.