The Inhibitory Effect of Lactobacillus rhamnosus GG on Vancomycin Resistant Enterococcus faecalis Colonization in Mouse

Abstract

Background&Aims: Vancomycin Resistant Enterococci (VRE) are among the most common nosocomial pathogens worldwide. The intestinal tract provides a major source for transmission of these bacteria. Probiotics are living microorganisms that moderate use of them has inhibitory effect on intestinal colonization by enteric pathogens. We examined the effect of Lactobacillus rhamnosus GG (LGG) on inhibition of VRE colonization in mouse model. Methods: Twenty four mice (Balb/C) were controlled for a week and then were infected to VRE by daily receiving of 1ml oral vancomycin (250µg/ml) and 1ml VRE suspension in MHB ( 5 10 CFU / ml 8 × ) for one week. Mice were randomly divided into two groups of treatment and control, and the effect of LGG probiotic was compared in the tow groups. VRE, total Enterococci, and enteric gram-negative bacilli counts in feces were determined before and after colonization by VRE. Results: At first, all mice were colonized by non –Vancomycin Resistant Enterococci (mean 5×105CFU/g for 7 days), and Vancomycin resistance was not detectable. Following gastric inoculation of VRE and receiving oral vancomycin, VRE was colonized in gastrointestinal tract of all mice (mean 1.6×106CFU/g for 7 days). Oral administration of LGG suppressed growth of all Enterococci, including the vancomycin-resistant strain in treatment group feces (P<0. 05). Conclusion: It is concluded that probiotic can reduce colonization of VRE. More studies on the effect of probiotics in prevention and treatment of VRE and other common pathogens are suggested