engleski

Experimental models to study the impact of food related conditions on virulence properties of poultry meat isolate Campylobacter jejuni

Introduction: Campylobacter jejuni has become the leading cause of human inflammatory enteritis and of the most important zoonosis worldwide. despite of high prevalence of human campylobacteriosis, mainly transmitted by food, extraintestinal survival and virulence properties of thermotolerant campylobacters are still poorly understood, also due to the lack of useful models for such studies. Methods and materials: We confirmed previously bacterial environmental stresses to be implicated in the adhesion, invasion and intraepithelial survival of C. jejuni in Caco-2 cells, J774 murine macrophages and PSI cell lines in in vitro models. In this work BALB/c mice were experimentally infected with stressed C. jejuni cells to mimic the infection in vivo. After bacterial spreading and tissue invasion we followed the survival of stressed cammpylobacters (exposed to starvation or short term oxidative stress) at 1, 3 and 8 days post infection in the organs (liver, spleen) of infected animals. Results: Colonisation of untreated as well as stressed campylobacters occured in the livers and spleens of BALB/c mice. Starvation impaired the ability of Campylobacter to persist in organs, however, short term exposure to oxygen enhanced its survival and therefore also the duration of infection with Campylobacter pre-exposed to short term oxidative stress. Conclusions: C. jejuni can adapt to environmental oxidative stress and modulate its intestinal epithelial cell interactions, such as adherence, invasion, and intraepithelial survival. Adaptive stress response in food or in food processing environment is thus crucial not only for extra-intestinal survival of Campylobacter cells, but also during host pathogen interaction and thus for its pathogenicity. In vivo studies have confirmed our current knowledge about virulence properties of C. jejuni 49/4 isolate from in vitro tests in conventional and also new functional model of the intestinal epithelium, e.g. noncarcinogenic small intestinal epithelial cells (PSI).

Campylobacter jejuni; environmental stress; bacterial virulence; cell monolayers.

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