Fecha de publicación: -- Fuente: "milk OR dairy products" Antonie Van Leeuwenhoek. 2026 Sep 10;119(10):213. doi: 10.1007/s10482-026-02426-3.ABSTRACTUrinary tract infections (UTIs) are among the most prevalent bacterial infections and are increasingly complicated by the emergence of multidrug-resistant uropathogens. The present study investigated the probiotic potential and anti-uropathogenic activity of Lactobacillus strains isolated from traditional dairy products in western Algeria using combined in vitro screening and an in vivo rat model of UTI. Uropathogenic bacteria recovered from urine samples of female patients were identified as Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Proteus vulgaris using standard microbiological methods and the API 20E identification system. Sixteen lactic acid bacteria isolated from raw milk and fermented dairy products were characterized phenotypically and identified by API 50 CHL and 16S rDNA sequencing as Lactobacillus acidophilus (n = 5), Limosilactobacillus fermentum (n = 4), Levilactobacillus brevis (n = 5), and Lactobacillus delbrueckii subsp. lactis (n = 2). In vitro assays demonstrated strain-dependent variations in cell surface hydrophobicity, autoaggregation, and phenol tolerance among the isolates. Most isolates showed susceptibility or intermediate responses to several clinically relevant antibiotics, while resistance was mainly observed to vancomycin, penicillin G, piperacillin, and nalidixic acid. Agar well diffusion assays revealed inhibitory activity against the principal uropathogens, with the strongest inhibition observed against E. coli. Two selected strains (L. acidophilus and L. fermentum) were further evaluated through intravesical administration in rats. The in vivo efficacy was strictly dependent on the frequency of administration; notably, a single-dose treatment was completely ineffective and failed to control leukocyturia or reduce pathogen colonization. In sharp contrast, precolonization followed by repeated instillations led to a dramatic clearance of the pathogen by day 11, reducing urinary E. coli counts down to 49 CFU/mL for L. acidophilus and 356 CFU/mL for L. fermentum. This repeated regimen also significantly controlled the inflammatory host response, with leukocyte counts decreasing from greater than 104 cells/mL to approximately 4 × 103 cells/mL by day 11, while successfully preventing kidney dissemination and minimizing bladder tissue damage. These findings highlight their potential as complementary strategies to prevent or mitigate UTIs.PMID:42720793 | DOI:10.1007/s10482-026-02426-3