Effect of probiotic strains on intestinal carriage of vancomycin-resistant Enterococcus faecalis
Résumé
Among intestinal pathobionts, enterococci, in particular vancomycin-resistant enterococci (VRE), are a leading cause in critically ill, elderly and immunocompromised patients of health-care associated and community-acquired infections with life threatening issues. Promoting intestinal resistance against enterococcal overgrowth after antibiotic treatments could reduce the risk of VRE infections. In this study, we investigated the effects of two Lactobacillus strains on intestinal VRE to evaluate the use of probiotic strains to prevent VRE infections.
We used an intestinal colonization mouse model based on a microbiota dysbiosis induced by clindamycin to mimic enterococci overgrowth and VRE establishment. Each probiotic was administered daily to mice starting one week before antibiotic treatment until two weeks after antibiotic and VRE inoculation. Enterococci increased transiently with clindamycin treatment and reached the highest level one day after stopping the antibiotic. Inoculated E. faecalis VRE evolved concomitantly to indigenous enterococci and persisted up to 11 days post-inoculation. No significant difference of VRE level was observed in Lactobacillus rhamnosus CNCM I-3690 treated mice compared to the control. Remarkably, administration of Lactobacillus paracasei CNCM I-3689 significantly decreased VRE level in the gut microbiota. Absence of growth inhibition of L. paracasei CNCM I-3689 on the VRE strain in vitro suggests an indirect effect on the gut microbiota or on the host. Transcriptomic analysis on a selection of host genes and whole microbiota analysis are underway to understand how L. paracasei CNCM I-3689 favors intestinal colonization resistance against VRE. Ultimately, this work will contribute to propose non-antibiotic prophylactic strategies against opportunistic enterococci after antibiotic dysbiosis.