STUDY OF BENEFICIAL PROPERTIES OF Lactobacillus brevis L52 TO BE CONSIDERED AS PROBIOTIC STRAIN

GERBALDO, GISELA; ASURMENDI, PAULA; PASCUAL, LILIANA; BARBERIS, LUCILA

Córdoba

Congreso; XI Congreso Argentino de Microbiología General; 2015

Probiotics have been defined as live microorganisms which when administered in adequate amounts confer a health benefit onthe host. Generally, strains that belong to the Lactobacillus genus are good candidates to be considered as probiotics bacteria. A list of criteria has been described for the selection of specific lactobacilli strain as potential probiotic agent, and beneficial properties are some of these desired characteristics. Moreover, probiotics results an important strategy for reducing the incidence of post-weaning diarrhea, a main problem in swine production. Lactobacillus brevis L52 was isolated from brewer´sgrains, a substrate used as an alternative swine feedstuff. The aim of this study was to evaluate the beneficial properties of L.brevis L52, a potential probiotic strain to be used in pig diet. Auto-aggregation test, surface hydrophobicity properties, acid and bile salt tolerance, antimicrobial activity and antibiotic resistance were determined. Lactobacillus brevis L52 showed 16% of auto-aggregation and aggregated with an ammonium sulfate solution of 1,5 mol/L; according to the salt aggregation test (SAT),strain L52 exhibits intermediate surface hydrophobicity properties. These characteristics suggest that L52 strain could form biofilms and colonize intestinal surface, which are a barrier against colonization by pathogenic microorganisms. Regarding to gastrointestinal condition tolerance, 92% and 30% of the total lactobacilli survived to pH 3 and pH 2, respectively. L52 toleratedall bile salt concentration assayed (0,1%, 0,3%; 0,5% and 2 %) and the maximum reduction lactobacilli count was of 10% with2% of bile salt solution. Antimicrobial activity was tested by the streak-diffusion method, allEscherichia coli (n=15) and Staphylococcus aureus (n=15) strains were inhibited by L52. The mean inhibition halos were of 39 mm and 33 mm, respectively for each pathogen microorganism. Antibiotics commonly used to prevent post-weaning diarrhea in pigs were assayed. L52 cellswere sensitive to ampicillin, tetracycline, gentamicin, kanamycin, and amoxicillin; and resistant to vancomycin and nalidixic acid. In conclusion, these preliminary results suggest that L. brevis L52 exhibits excellent properties to colonize intestinal epithelium,to pass through gastrointestinal tract and to inhibit pathogenic bacteria growth. Accordingly, L52 is an important candidate to be considered as potential probiotic agent for biocontrol diarrhea pathogens and improve pig health.