Characteristics And Their Relationship Of Pulsed-field Gel Electrophoresis Typing, Antibiotics Resistance And Virulence Genes Distribution Of Campylobacter Isolates

Campylobacter is a self-limiting, Gram-negative pathogen, and it is the main reason for intestinal diseases worldwide. C. jejuni and C. coli are responsible for the majority of human Campylobateriosis, and maybe lead to serious neurological diseases. Campylobacter is commonly carried bypoultry, especially in chicken intestinal, and it can pollute the environment through excreting fecaL Human could obtain Campylobacter via direct contact or consumption of chicken products in indirect ways. The incidence of Campylobacteriosis and its antibiotics resistance have been rising during recent years. It’s a serious threat to human health. To improve the cure rate of campylobateriosis, we should limit the absue of antibiotics, also control polluted sources. The main purposes are to study:(1)genetic relationship of Campylobacter jejuni isolated from different hosts by pulsed-field gel electrophoresis, the distribution of virulence genes and antibiotics resistance, and the correlation of the three methods;(2)cross-contamination in the processes points of chicken meat production in a slaughter plant through the comparison of pulsed-field gel electrophoresis, the distribution of virulence genes and antibiotics resistance results.1. Characteristics and their relationship of pulsed-field gel electrophoresis typing, the distribution of virulence genes and antibiotics resistance of Campylobacter jejuni isolated from different hostsIn this study, the pulsed-field gel electrophoresis, antibiotics resistance, and virulence-related genes of88Campylobacter jejuni strains, which were isolated from patients with diarrhea in Yangzhou, poultry and cattle. Results showed these pathogens can be divided into9PFGE types (PTs). Of these PTs, PT9was consistent of30isolates, accounted for34.1%of total bacteria, and was the main PT of Yangzhou City. In the PT9, majority strains were isolated from human and chicken, accounted for86.7%total bacteria of PT9. In the other PTs, strains isolated from human and chicken had the higher rate existed in the same PT. These reflected the relation of isolates from human and chicken were close, and the diarrhea may have relation to chicken.The distribution of most pathogens of the same PT was similar. The distribution of some pathogens was the same. For example,57.1%of the pathogens isolated from human of PT2had the same virulence genes distribution, and63.6%of pathogens isolated from chicken of PT9had the same virulence genes distribution The homo logy of isolates of PT2and PT3was relatively bw, and the difference of their distribution of adhesion-related genes was large. These showed the distribution of virulence genes and homology had certain relations. The difference of distribution of lipopolysaccharide-, toxin-, and tropism-related genes of isolates from different PTs was not very large, and many pathogens had the same distribution of virulence genes. These isolates, PO-10, PO-17-7, PO-18-2of PT8and PT9had similar distribution of virulence genes, and they only had resistance of cefoperazone (CEF) different. The isolates, XN-4-2, DJ-2-4, and TZDN-8of PT7had similar distribution of virulence genes, and their resistances were mostly the same.Results showed that there was no one to one correspondence between PFGE types, virulence genes and antibiotics resistance of C. jejuni. But isolates of different PTs had different similarity degree of virulence genes distribution, and C. jejuni of PT8and PT9, which were isolated from human, chicken and cattle had high similarity of antibiotics resistance.2. Cross-contamination of Campylobater through the process pionts of chicken meat productionIn this study, we made use of pulse-field gel electrophoresis, antibiotics resistance and distribution of virulence genes to monitor the process points of chicken meat producton of a slaughterhouses of Nantong. We monitored seven points of chicken meat production, including feather removal-before, feather removal-after, gut-after, cecum content, disinfectfon, packaging and freezing. Of41Campylobacter we obtained,38were C. coli and3were C. jejuni. Results of PFGE showed38pathogens could be divided into3PTs, and the homology of these strains was higher than90%. Isolates from different process points of chicken meat production commonly had the same PT, and this result showed the homology of the isolates from the different process points was high. Of these PTs, isolates F46、F6ofPT2, and B14、D52、F44、D59of PT3had the same distribution of virulence genes and resistance. This result showed these isolates could be derived from the same chicken carcass, and this reflected cross-contamination of different process points of chicken meat production. Gut-after, cecum content and packaging process points all had isolates of the same distribution of virulence genes, and this showed cross-contamination of the same process. The process points of disinfection and freezing had few isolates, which had the same distribution of virulence genes of other strains, and the rest process points had more isolates of the same distribution of virulence genes. These results showed process points of feather removal-after, gut-after, cecum content, and packaging had significant cross-contamination, and process points of disinfction and freezing had lighter cross-contamination.Result of pathogens isolated from different process points of chicken meat production showed that PFGE had high resolution, high practical and high sensitivity, and could analysis the homology of isolates. So PFGE is a very effective molecular typing method, and the establishment of PFGE fingerprint database of Campylobacter could trace the origin of Campylobacter timely, and control the occurence of food borne diseases.