Virulence gene distribution and molecular typing of Campylobacter isolates from duck- slaughter chain in Chengdu,China
LI Jia-kang1, 2, HUANG Xue-lin1, 2, ZENG Hang3, YANG Lei1, WU Meng-yu1, 2, XUE Yan1, SHEN Yu-xi1, 2, HUANG Yong1, 2, ZOU Li-kou4, HAN Xin-feng1, 2
1. College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, China; 2. Key Laboratory of Animal Diseases and Human Health of Sichuan Province, Chengdu 611130, China; 3. College of Food Science, Sichuan Agricultural University, Yaan 625014, China; 4. College of Resources, Sichuan Agricultural University, Chengdu 611130, China
Abstract:To understand the virulence gene distribution and molecular typing characteristics of Campylobacter isolates from duck slaughter chain, a total of 9 virulence-associated genes of Campylobacter spp. were investigated by PCR to assess the potential risk to human. In addition, 68 isolates of Campylobacter were subjected to genotype analysis using pulsed-field gel electrophoresis (PFGE) according to the method of PulseNet. The results indicated that the most commonly observed virulence genes were cadF (100%), iamA (100%) and cheY (100%) in 35 strains of Campylobacter jejuni, followed by flaA (97.1%), cdtB (94.3%), cdtC (94.3%) and ciaB (80%). The occurrence of virulence genes of cdtA (25.7%) and virB11 (2.9%) were lowe. As for Campylobacter coli, the virulence gene of cadF (100%) was observed in all the 33 isolates, followed by cheY (84.8%), cdtB (72.7%), iamA (66.7%) and cdtA (54.5%). The virulence genes of flaA (48.5%), virB11 (18.2%), cdtC (36.4%) and ciaB (18.2%) had low carrying rates. In the PFGE molecular typing, the band similarity coefficient greater than 85% was regarded as the identical genotype. The PFGE results showed that 35 strains of Campylobacter jejuni and 33 strains of Campylobacter coli could be divided into 15 and 11 patterns, which were characterized by lower genetic diversity. The analysis of the genotypes of Campylobacter isolates indicated that there was a cross contamination and transmission along the slaughter chain in the duck slaughterhouse. The virulence gene of Campylobacter is widely existed, and the carrying rate of Campylobacter jejuni is high. The similarity of PFGE gene profile indicated that there is cross infection and campylobacter transmission along the slaughter chain.
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