INVESTIGADORES
VERA PINGITORE Esteban
congresos y reuniones científicas
Título:
COMPARATIVE ANALYSIS OF VANCOMYCIN RESISTANCE AND BACTERIOCIN PRODUCTION BY Lactobacillus salivarius STRAINS
Autor/es:
VERA PINGITORE E.; HEBERT E M.; SESMA F.; NADER-MACIAS M.E.
Lugar:
Tucumán
Reunión:
Simposio; II SIMPOSIO INTERNACIONAL DE BACTERIAS LÁCTICAS - Primer encuentro Red Bal Argentina; 2006
Institución organizadora:
CERELA - CONICET
Resumen:
Lactobacilli have long been considered to be protective flora in the vagina exerting a protective role against pathogen colonization by steric exclusion and production of inhibitory substances. Lactobacillus salivarius subsp. salivarius CRL 1328, a lactic acid bacteria isolated from vagina, produces a bacteriocin (salivaricin) with antimicrobial activity against Enterococcus faecalis, Enterococcus faecium, and Neisseria gonorrhoea which would allow its probable application in a probiotic for the prevention of urogenital infections. However, certain lactobacilli have vancomycin resistance which may not be advantageous because it can transfer the resistance to unrelated pathogenic or potentially pathogenic bacteria. In order to design a probiotic to prevent urogenital infections, we studied the vancomycin resistance and bacteriocin production by different strains of L. salivarius, isolated from different sources. Previously, we demonstrated that a salivaricin CRL 1328 cluster is composed of  two structural genes (a y b) encoding the bacteriocin, a specific immunity gene (IM), genes encoding an ATP-binding cassette (T y D) and regulatory genes (IP, K y R).The presence of salivaricin genes was verified by PCR using specific primers designed from the cluster described before. On the other hand, we designed specific primers for determining the presence of vancomycin resistance genes. All analyzed strains exhibited a PCR product for b gene. L. salivarius CRL 1414 displayed positive results for the presence of structural genes, regulatory genes and the immunity gene. Considering the genes involved in the bacteriocin transport, only DNA of L. salivarius CRL 1233 gave a PCR product. However, with exception of CRL 1328, none of the studied strains showed the complete cluster of salivaricin. This observation, could explain the absence of bac+ phenotype in the mentioned strains. Regarding the presence of vancomycin resistance genes, only L. salivarius CRL 1233 displayed an amplification band for vanC1 gene (ligase). However, all evaluated strains showed resistance to 50 µg/ml of this antibiotic. These observations would indicate that the analyzed strains possess a vancomycin intrinsic resistance such as their potential use in human health would not be affected by horizontal transfer. Our results indicated that L. salivarius CRL 1328 could be used as probiotic for the prevention of urogenital infections