CERELA   05438
CENTRO DE REFERENCIA PARA LACTOBACILOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
SAFETY CHARACTERISTICS OF LACTIC ACID BACTERIA ISOLATED FROM FEEDLOT TO BE INCLUDED IN A PROBIOTIC PRODUCT
Autor/es:
ARISTIMUÑO FISCOSECO CECILIA; VIGNOLO GRACIELA; MALDONADO NATALIA; MANSILLA FLAVIA; MELIAN CONSTANZA; NADER MEF
Lugar:
San Miguel de Tucumán
Reunión:
Simposio; V Simposio Internacional de Bacterias Lácticas (SIBAL); 2016
Institución organizadora:
CERELA-CONICET
Resumen:
Since 2006, European Unionlegislation has banned the use of antibiotics as growth promoters in animal husbandry. Antibiotic use may contribute to the emergence of antibioticresistance bacteria in humans, because genesspreading through food chains may occur. Consequently, the addition of probioticsto diets has gained increasing importance in animal nutrition and health constituting a novel alternative to replace antibiotic growth promoters.As part of the research work, Lactic Acid Bacteria (LAB) were isolated and identified from feedlot environment and their beneficial properties were investigated. In this study, safety characteristics such as antibiotic resistance genes and virulence factors as hyaluronidase, gelatinase and/orhemolysis of LAB strains intended to be used as animal probiotic formula,were evaluated. The antibiotic resistance was examined by phenotypic and genetic assays using the following antimicrobials: Ampicillin, Tetracycline, Chloramphenicol, Gentamicin, Streptomycin, Kanamycin, Vancomycinand Erythromycin. The minimum inhibitory concentration (MIC) was determined by agar dilution method in LSM media. Forty LAB strains wereevaluated(27 Lactobacillus, 11Enterococcusand 2Pediococcusacidilactici) and the European Food Safety Authority (EFSA) proposed cutoff valueswere applied. By PCRusing specific primers, the presence of antibiotic resistance genes (bla,cat,erm(B), erm(C),aac(6´)-aph(2´´),aph(3´´)-III,strA,strB,aadA,aadE,ant(6),tet(M),tet(K),tet(L),tet(S),vanA, vanB andvanX)were evaluated, whereas phenotypic assays in agar solid media with specific substrates were used for virulence factors detection.Results showed different antibiotic susceptibility/resistance patternsdisplayed by LAB, all of them beingsensitive to VANand AMP, while80.5% of the strainsresistant to TETwere mostlyisolated from animal feces.In addition, resistance toERY (58%), CLI(38.5%), CHL (12%), STR (10%) andKAN(3%)was detected inLAB strains.Lactobacillusweremore susceptible to CLI/ERY/GEN than Enterococcus.MIC values one dilution higher than the cutoffwere observed forLactobacillusand Enterococcusresistance to STR/GEN and GEN/CLI/ERY, respectively.With the exception of VAN genes, the presence of coding genes for AMP/KAN/CHL/TET/ERY/STRwas found. In addition, all of the assayed LAB strains were free of virulence factors. The incidence of antibioticresistance traits together with the lack of virulence factors helped to select LAB strains to be included in the design of a probiotic formula for steers in feedlot.