Antimicrobial effect of Lactobacillus in a rat model of Escherichia coli urinary tract infection: A preliminary study

Purpose: Urinary tract infection (UTI) is one of the most common infectious diseases. There are reports that loss or destruction of normal urinary flora such as Lactobacillus increases UTI, and in more recent reports, human urinary epithelial cells have been found to competitively block uropathogen conjugation. We investigated the blocking effect of the Lactobacillus rhamnosus in a rat model of UTI caused by Escherichia coli. Materials and Methods: Thirty-two adult female Sprague-Dawley rats weighing 250 to 350 g (Samtako BioKorea, Osan, South Korea) were randomly divided into 4 groups (Group I, control group; Group II, Lactobacillus group; Group III, E. coli group; Group IV, E. coli and Lactobacillus group). After 3 weeks, the urine and bladder were cultured for microbiological study and the bladder was examined histopathologically. Results: Microbiological culture of urine demonstrated no significant differences in the four groups, but there were significantly fewer bacteria in group IV than in group III (p<0.05). The bacterial growth of the bladder tissue showed the same result. Histological exam of the bladder of group IV showed decreased infiltration of leukocytes and less submucosal edema than in group III. Conclusions: We were able to confirm the blocking effect of L. rhamnosus on E. coli growth. More studies are needed to further identify the therapeutic effect of Lactobacillus and to determine the optimal lactobacilli species, dose, and method of administration.