Effect Of Different Conditions On Adhesion And Invasion Of Campylobacter Jejuni

Campylobacter jejuni is a food-borne pathogen which can cause intestinal inflammation and secondary meningitis, joint sepsis, Guillain-Barre Syndrome through invasion of ???estinal epithelial cells. It is widespread in birds, poultry intestines and the natural environment.A large number of data show that C.jejuni invation rate of human not less than Shigella and Salmonella which has been a serious threat to food safety and human health.But the current treatment and virulence factors of C.jejuni are still not clear.The aim of this study was to investigate the growth and invasion of C.jejuni under different conditions. Based on the previous studies, we further studied the pathogenic mechanism of Campylobacter jejuni and elucidated the pathogenic and survival characteristics for the prevention and control of this strain. The growth of C.jejuni in NaCl,KCI, MgCl₂, MnCl₂. CaCl₂, bile salt, cholic acid and different pH was compared during the experiment. It was concluded that the addition of bile salt and cholic acid had little effect.The growth of C.jejuni was inhibited by the addition of 1% NaCl, KCI, MgCl₂ and pH 6,but not death. Next, the intestinal epithelial cells HCT-8 were invaded with C.jejuni under 1% NaCl, KCl, MgCl₂ and lactic acid?adjusted to pH 6? or hydrochloric acid?adjusted to pH 6?. The results showed that hydrochloric acid ?adjusted to pH 6? effects infection most significantly.We construct the adhesion and invasion model of C.jejuni ATCC33560 in vitro. The C.jejuni cultured at pH 7.0 ?control group?;cultured,adhesion and invasion at pH 7.0?adhesion and invasion group? and cultured adhesion and invasion at pH 6.0?acid tolerance group? were used to analyze by High - throughput Whole Genome Sequencing.Gene expression profiles showed a differential expression of some genes in adhesion and invasion group and acid tolerance group compared with control group. Among them, genes related to flagellum, lipopolysaccharide synthesis, iron-related genes, fatty acid metabolism and tryptophan metabolism were up-regulated. And genes related to glucose metabolism and TCA cycle were down-regulated. Although the infection rate of the bacteria was improved by acid tolerance, the difference was not much between the adhesion and invasion group and the acid tolerance group. Some genes in the transcriptome data were selected and validated by real-time quantitative PCR. The qRT-PCR results showed that the transcriptome sequencing was believable. In this study, we got some information in the gene expression profile of C.jejuni, when the strain adhere and invade to intestinal epithelial cells under acidic conditions. This information may be helpful in the pathogenesis clarify of gastrointestinal infection.