In vivo versus in vitro metabolomics profiling of vaginal lactobacilli for probiotic use

2^nd International Conference and Exhibition on Metabolomics & Systems Biology

April 08-10, 2013 Hilton Chicago/Northbrook, USA

D E O?Hanlon

Scientific Tracks Abstracts: Metabolomics

Abstract :

Vaginal microbiotas dominated by lactobacilli are associated with reduced reproductive tract disease, including sexually transmitted infections. Lactobacilli that produce hydrogen peroxide (H 2 O 2 ) h2o2 under specific experimental conditions confer greater protection, compared to lactobacilli that do not produce H 2 O 2 under the same conditions. H 2 O 2 production is a generally used criterion in selecting lactobacilli for probiotic use. However, the vaginal environment precludes significant in vivo production or accumulation of H 2 O 2 . H 2 O 2 -production is therefore an experimental metabolomics marker of protective lactobacilli, rather than a direct mechanism of in vivo protection. We investigated the metabolomic-profiles of vaginal lactobacilli in vivo and under different in vitro conditions. We compiled in vivo metabolomic-profiles by measuring metabolites (H 2 O 2 , lactate, acetate and hydrogen ions) in freshly collected cervicovaginal fluid samples maintained under physiological conditions. We isolated the lactobacilli from the samples and measured metabolites under various in vitro conditions. In vivo , and in conditions consistent with those in vivo , H 2 O 2 -production was trivial or undetectable (~ uM) and lactate production was high (1%). Under typical ?experimental? conditions, however, H 2 O 2 -production was 1000-fold higher and lactate production was 10-fold lower. We found a general correlation of high H 2 O 2 -production under experimental conditions with high growth rate and high lactate-production under in vivo conditions. However, the correlation is not perfect: the lactobacilli strain with the highest growth rate and lactate-production did not have the highest H 2 O 2 -production. We believe that H 2 O 2 -production under experimental conditions is a spurious criterion for selecting probiotic strains, and should be replaced by growth rate and lactate-production under physiological conditions.