Norfloxacin treatment on E. coli in the urinary tract of mice: Effect of probiotic Lactobacilli

Abstract

This study was perfomed to evaluate the effect of the treatment of norfloxacin, as an antimicrobial agent, on the uropathogenic Escherichia coli colonization in mice, complemented by Lactobacilli as probiotics. Norfloxacin (5.5 mg. Kg-1 dose) was administred orally before and after the challenge with E. coli. The animals were also inoculated intra-urethrally with agarose beads containing L. fermentum. The population of the microorganisms in the urogenital tract was measured various days throughout the study. Using either 1 or 3 doses of norfloxacion befor or after the animal had been challenged with E. coli bacteria, reduced the E. coli population the urinary tract. The Norfloxacin treatment after the animals were administered 1 or 3 doses of agarose beads of lactobacilli significantly affected the viability of the lactic acid bacteria in all of the urinary tract organs and the number of E. coly (regardless to when the antibiotic was inoculated) was lower in the mice treated with lactobacilli than in the non-lactobacilli treated mice. Eventhough the survival of the lactobacilli was highly affected by the norfloxacin treatment, the uropathogenic E. coli colonization always decreased more than the lactobacilli population did and often completely disappeared in those animals which were treated with both norfloxacin and probiotic lactobacilli. Through this experimental model one can conclude that lactobacilli increases the effectiveness of the norfloxacin medication in the prevention and treatment of UTI produced by E. coli. Further studies are being performed to determine the mechanisms involved in this probiotic effect.