IN VIVO ASSESSMENT OF THE EFFECT OF DIET ON TIME-COURSE OF INFECTION IN MICE USING BIOLUMINESCENT BACTERIAL PATHOGENS

摘要

Milk components are known to have a variety of biological functions in addition to basic nutritional properties including opioid, antimutagenic, antimicrobial and immunomodulating activity. It has been reported that intake of milk fermented by lactic acid bacteria (LAB) produces a specific humoral immune response. In our previous research, it was shown that cell-free fractions of fermented milks enhanced cytokine production of macrophages in vitro. However, such assays are expensive and difficult to perform. It is also difficult to extrapolate the results of these assays to events that occur in whole animals. Thus, to establish the biological relevance of this phenomenon, an in vivo model has been proposed to assess the effect of fermented milk and its components on the course of bacterial infections in mice. Colonization of the gastrointestinal tract by bioluminescent pathogens can be monitored in live animals during experimental infections in real-time. We propose to use this approach to assess the effect of food components by monitoring the time course of infection in animals that were fed with the product prior to infection. Test mice were first fed with products and then infected orally with a luminescent strain of S. Enteritidis. The infectivity of this pathogen was then assessed in living intact mice by monitoring bioluminescence together with visual signs of infection and postmortem (PM) histological and bacteriological analysis.