Caracterización in vitro de propiedades probióticas de Lactobacillus ssp. aislados del tracto digestivo de abejas

The present work aimed at characterizing in vitro the lactic acid bacteria Fructobacillus fructosus SS66, Lactococcus garvieae SS79, Fructobacillus fructosus SS72, Lactobacillus kunkeei SS70, Lactobacillus rhamnosus SS73, isolated from the digestive tract of bees Apis mellifera . Their probiotic capacity was evaluated by enzymatic tests, growth stability at different temperatures (37 and 45°C) at a range of pH (3.5; 4.5; 5.5; 5.5; 6.5), tolerance to artificial gastric juice (AGJ), bile salts (0.3, 05 and 1 %), and adhesion tests such as aggregation, self-aggregation and hydrophobicity and microbial antagonism.. The results showed that all strains grew at 37°C at acidic pH 6.5 and 5.5 and did not grow at pH 4.5; they produced hydrogen peroxide and did not reveal hemolytic activity. The strains tolerated AGJ pH 3 for 3 h at 37 °C and bile salts up to 1%. No strain showed self-aggregation and only two ( L. rhamnosus SS73 and L. kunkeei SS70) produced co-aggregation against Escherichia coli . Hydrophobicity was variable among the strains, F. fructosus SS72 exhibiting a high value, L. rhamnosus SS73 and L. kunkeei SS70 a medium value and L. garvieae SS79 and F. fructosus SS66 a low one. All strains showed a broad spectrum of antimicrobial activity and inhibitory effect against Paenibacillus larvae and other human and animal pathogens. The best-performing strains were L. kunkeei SS70 and L. rhamnosus SS73, which were susceptible to the antimicrobial agents used, with the exception of Sulfonamide and Vancomycin. From these results, they can be incorporated into a probiotic inoculum to evaluate their effect in vivo .