Safety characteristics of beneficial vaginal lactic acid bacteria (lab) to be included in a probiotic product

ANTONELLA MARCHESI; M.E.FATIMA NADER; CECILIA ARISTIMUNO; JESSICA SILVA

Mar del Plata

Congreso; "Reunion conjunta SAIC-SAI-SAFE 2016"; 2016

SAIC-SAI-SAFE

The women vaginal tract infections are one the most frequent gynecologist attendance, being usually treated with antibiotics, which can contribute to the emergence and spread of resistance in humans. The application of probiotics as preventive or therapeutic agents is being applied for women´s health and constitutes a novel alternative to replace the excessive use of antibiotic. Our research group is working on the design of probiotic formulations with autochthonous lactic acid bacteria (LAB) isolated from the female human vagina, and their beneficial characteristic were previously evaluated. In this study, safety characteristics such as the antibiotic resistance (by genetic and microbiological assays) and virulence factors (hyaluronidase, gelatinase and hemolysis capability) of LAB strains selected by their beneficial properties were evaluated to include them in the design of a probiotic formula for the vaginal tract. The antibiotic resistance was studied by phenotypic and genetic assays using the following antimicrobials: Ampicillin, Tetracycline, Chloramphenicol, Gentamicin, Streptomycin, Kanamycin, Vancomycin and Erythromycin. The minimum inhibitory concentration (MIC) assay was performed by the plate diffusion technique with lactobacilli in LSM media agar and antibiotic in the wells, later incubated in microaerophylic conditions at 37°C. The beneficial strains studied were Lactobacillus reuteri, L. gasseri, L. rhamnosus, L. salivarius, applying the European Food Safety Authority (EFSA) cutoff values. The presence of antibiotic resistance genes (vanA, vanB and vanX erm(C), bla, cat, erm(B), aac(6´)-aph(2´´), aph(3´´)-III, strA, strB, aadA, aadE, ant(6), tet(M), tet(K), tet(L), tet(S)) were evaluated by PCR using specific primers. Phenotypic assays in agar solid media with specific substrates were used for the detection of virulence factors. There is a wide degree of coincidence between the results obtained in the phenotypic and genotypic resistance pattern of the strain to the different antibiotic. Furthermore, the results indicate the resistance to ERY (80% of coincidence between phenotypic and genotypic studies) for all the strains assayed. L.rhamnosus CRL1508 and L.rhamnosus CRL1511 showed coding genes for TET/VAN. In addition, L.gasseri CRL1267 and L.reuteri CRL1327 were resistant to CLIN (50%) and KAN (50%) in phenotypic assay. Most of the strains were sensitive to CHLOR/STRE/GEN, which are the antibiotic most frequently applied to the therapy of urogenital infections. All of the vaginal Lactobacillus strains studied were free of virulence factors. The results of this work indicate that the LAB are safe and can be included in the design of a pharmabiotic product to restore the vaginal microbiota and prevent infections.