Survival of beneficial vaginal lactic acid bacteria to gastrointestinal simulated condition

ANTONELLA MARCHESI; MARIA ELENA FÁTIMA NADER; JESSICA SILVA

Rosario

Congreso; 4ta Reunion Internacional de Ciencias Farmaceuticas (RICIFA); 2016

Universidad Nacional de Rosario y Córdoba

The increase of the knowledge on the vaginal human microbiome, and the dominance of lactobacilli in the human vaginal-tract encourage the application of vaginal probiotic applications for preventive and therapeutic goals. Our research group is working on beneficial vaginal-lactic-acid-bacteria (VBLAB) for the design of vaginal pharmabiotic-products. The aim of this work was to evaluate if the VBLAB survive simulated gastrointestinal conditions, to be later included in the design of an oral formula, on the hypothesis of the ascendant colonization from rectum to the vaginal-tract. The simulated conditions were assayed with different bile salt concentration, pH and enzymes. The lactobacilli species were: Lactobacillus reuteri, L.gasseri, L.rhamnosus and L.salivarius. Cultures of each strain in the exponential phase were inoculated in microwells plates. The optical density (OD560nm) of the growth was determined at 3,6,9,12 and 24h, with different bile salt concentration (0.25,0.5,1,2%) and pH (3.5,4.5,6.5). The simulated tract conditions were performed as follows: the oral cavity enzymes (amylase-lysozyme) were added to bacteria (108CFU/ml) in tubes for 15 minutes. The cells were added to gastric juice conditions (pepsin-bile salts) for 90 minutes. Later, the bacteria were exposed to pancreatin, chymotrypsin and trypsin during 120 minutes. The number of survival bacteria was determined by the successive dilution-method in agar plates. The results obtained show that L.reuteri CRL1327 and CRL1324 were the most resistant strain to salt and pH with a 25% and 40% decrease of the growth, while L.rhamnosus CRL1332 and L.salivarius CRL1328 were more sensitive, with a decrease around 65%. The resistance of the strains to the stressful single conditions of the gastrointestinal-tract indicates a similar behaviour in the sequential experiments with enzymes, low pH and bile salts. The results obtained help us to continue working on the design of an oral formulation with VBLAB-gut conditions survived- for the restoration of the urogenital-tract microbiome.