Preventive effect of Lactobacillus reuteriCRL1324 on Group BStreptococcus vaginal colonization in an experimental mouse model

Aims To assess the preventive effect of different intravaginal (i.va.) doses of Lactobacillus reuteriCRL1324 against vaginal colonization by Group B Streptococcus (GBS) in a murine experimental model. Methods and Results The major virulence factors of four vaginal GBS clinical isolates were determined to select the most virulent strain and set up a murine model of streptococcal vaginal colonization. Later, the effect of four and seven doses of 108 viable cells of Lact. reuteri CRL1324 i.va. administered, prior to the GBS challenge was studied. Seven doses of lactobacilli were able to significantly reduce the number of viable GBS cells, while four doses showed no preventive effect. Both doses reduced the leucocyte influx induced by GBS. Seven doses caused a slight increase in the Lact. reuteri CRL1324 vaginal colonization compared with four doses and reduced murine vaginal pH compared to control mice. Conclusions Lactobacillus reuteriCRL1324 evidenced a preventive effect on GBS vaginal colonization in an experimental mouse model. Significance and Impacts of the Study Maternal GBS colonization is one of the most important risk factors for developing disease in newborns. Lactobacillus reuteriCRL1324 could be considered as a new biological agent to reduce infections caused by this micro-organism.