EFFECT OF LACTOBACILLI AND ANTIBIOTICS ON ESCHERICHIA-COLI URINARY INFECTIONS IN MICE

Urinary antibiotic treatments usually affect the normal urethral flora , This work was developed in order to evaluate whether Lactobacillus f ermentum CRL 1058 could reduce urinary tract infections (UTI) produced by uropathogenic Escherichia coli in mice treated with antimicrobial agents. Animals were inoculated intra-urethrically with agarose beads containing lactobacilli, and were challenged with E. coli, Ampicillin (13 mg/kg/dose) was administered orally. The number of microorganisms present at different days was evaluated in the urogenital tract, Serum inflammatory and systemic immune response mere also registered. The u se of 5 doses of ampicillin after 3 doses of lactobacilli in agarose b eads significantly affected the viability of lactic acid bacteria, whi le the amount of E, coli was not altered. Lactate dehidrogenase (LDH) activity and anti-E. colo antibody levels showed no statistically sign ificant difference between the challenged and non-challenged mice. Lac tobacilli reinoculation and 3 doses of ampicillin proved to be a moder ately effective treatment since a smaller amount of E. coli was recove red from the organs of treated mice than from the controls. The reinfo rcement of lactobacilli, administered on the 9th day, produced a faste r elimination of the pathogen. The ampicillin dose used allowed lactob acilli permanence in the urinary tract, and caused the elimination of the pathogen. Serum LDH values seemed to show an inflammatory immune r esponse. No successful preventive results could be achieved. We can co nclude that lactobacilli and adequately low doses of ampicillin have a positive effect on the treatment of E. coli in this UTI model.