Immunomodulation of Lactobacillus reuteri CRL1324 on Group B Streptococcus Vaginal Colonization in a Murine Experimental Model

Problem Maternal Group B Streptococcus (GBS) colonization is a risk factor for infectious disease in newborns. One promising strategy is the modulation of vaginal defense to increase the host's ability to combat infection. Method of Study The effect of intravaginal (i.va.) Lactobacillus reuteri CRL1324 inoculation on different immune cell populations, cytokines, and immunoglobulin isotypes in a murine model of GBS vaginal colonization was evaluated. Results Seven i.va. inoculations of L. reuteri CRL1324 previous to GBS challenge showed an immunomodulatory effect on the cells and mediators of innate immunity, decreasing the number of neutrophils induced by the pathogen and increasing the activated macrophage population. Moreover, increases in B lymphocytes and IgA and IgG subclasses were observed in mice inoculated with L. reuteri CRL1324 and then challenged with GBS. Conclusion Lactobacillus reuteri CRL1324 shows a protective effect against GBS colonization that could be mediated by the modulation of the immune response.