Abstract
Lactobacilli are part of the normal flora of the genitourinary tract. When present, they can competitively exclude uropathogenic microorganisms, being various the factors responsables of this inhibition: production of bacteriocins, acid, H2O2. As E. coli is one of the most frequent pathogens isolated from urinary infections in children and in pregnant women, the objective of this work is to study the H2O2 production by L. fermentum (isolated from the urogenital tract of mice) and its inhibitory effect against uropathogenic E. coli.
L. fermentum produces a maximun of 8.6 nmols/min/106 cells at 3 hours culture, being stable up to 24 hours. In mixed cultures of lactobacilli and E. coli, the inhibition increases by addition of mieloperoxidase and halide.; at 4 hours, the pathogen decreases from 109 to 107 CFU/ml, while the lactobacilli is stable. The number of viable microorganisms was determined by the succesive dilution method, employing selective culture media. Our results reflect the importance of H2O2 produced by lactobacilli and the peroxidase present in the urogenital ecosystem as an inespecific defense mechanism and of bacteria antagonisms against the urinary infections producer pathogens.
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De Bocanera, M., De Macias, M., De Ruiz, C. et al. CONTROL OF UROPATOGENIC E. COLI BY LACTOBACILLUS FERMENTUM PRODUCER OF H2O2. Pediatr Res 36, 824 (1994). https://doi.org/10.1203/00006450-199412000-00029
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DOI: https://doi.org/10.1203/00006450-199412000-00029