CONICET | Buscador de Institutos y Recursos Humanos

A wide variety of microbial species is used in food and feed productionworldwide. Some have a history of safe use while others are less wellunderstood and their use may represent a risk for consumers. Probiotics arelive microorganisms which, administered in adequate amounts, exert a beneficialeffect on the health of the host. Taking into account the worldwide obesityepidemic and the importance of using new probiotic strains for this disease,our working group selected strains which showed probiotic effects in animalmodels of diet-induced obesity. The study of beneficial properties attributedto isolated microorganisms constitutes a field of interest for the developmentof functional foods. A fundamental requirement that contributes to thedevelopment of these foods is to determine the degree of food safety ofprobiotic strains before they are marketed. Lactobacilli are generally regardedas safe (GRAS) and most of them are included in the Qualified Presumption ofSafety (QPS) list of the European Union due to the long history of use infermented dairy products and their presence in the human intestinal tract.However, certain Lactobacillus strains have been associated with casesof sepsis, endocarditis, or bacteremia, mostly in association with a severeunderlying disease. On the other hand, the absence of acquired antimicrobialresistance is an important criterion for evaluating the safety of lactic acidbacteria used as food started or probiotics. The aim of this study was toevalue the safety of strains with probiotic potential in obesity: Lactobacilluscasei CRL431, Lactobacillus fermentum CRL1446, Lactobacillusplantarum CRL353 y Lactococcus lactis 1434. Our workgroup hasassessed many functional properties of this Lactobacillus strains, butparameters regarding safety must be studied before calling them probiotics. Inthis work, safety aspects of Lactobacillus strains were studied. None ofthe strains tested caused a- or b-hemolysis. All the strains were susceptible totetracycline, clindamycin, streptomycin, ampicillin, erythromycin, kanamycin,gentamicin, vancomycin and chloramphenicol. We also did not find antibioticresistance genes for any of the strains studied. Mice treated daily with anoral dose of 108 CFU during 21 days showed no signs of pain, lethargy,dehydration, or diarrhea, and the histological studies were consistent withthose findings. No translocation of microorganisms to blood, spleen, or liverwas observed. Regarding these findings, Lactobacillus casei CRL431, Lactobacillusfermentum CRL1446, Lactobacillus plantarum CRL353 y Lactococcuslactis 1434 strains are microorganism GRAS with a great potential asprobiotic for obesity.

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