Activité antimicrobienne des bactéries lactiques vis-à-vis des infections urinaires.

Abstract

Lactic acid bacteria are widely used in the agri-food industry due to their essential role in food fermentation and preservation processes. Among them, the genera Lactobacillus, Streptococcus, and Bifidobacterium are particularly known for their antimicrobial properties and beneficial effects on human health. In this context, the present study focused on five local strains of lactic acid bacteria, all Grampositive and catalase-negative, in order to evaluate their antimicrobial potential against uropathogens. The collection studied includes five strains belonging to the Lactobacillus genus: Lactobacillus acidophilus LB13, Limosilactobacillus fermentum LB25b, Lactobacillus brevis LB31, Limosilactobacillus fermentum LB02, and Lactobacillus acidophilus LB32. Urinary tract infections (UTIs) encompass a range of conditions caused by the colonization of the urinary tract by pathogenic bacteria, referred to as uropathogens. These infections can affect the urethra, bladder (cystitis), ureters, or kidneys (pyelonephritis). They are mostly caused by Enterobacteriaceae, particularly Escherichia coli, which accounts for over 80% of cases, as well as other pathogens such as Proteus spp. and Klebsiella. Their high prevalence, especially among women, makes them a major public health concern. To assess the antimicrobial activity of the lactic acid strains, the well diffusion method was employed. This approach allowed the evaluation of the inhibitory effects of antimicrobial substances produced by the lactic acid bacteria on four reference pathogenic strains: Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Proteus vulgaris. The results showed significant inhibition of these pathogens' growth, with inhibition zones ranging from 11 to 21 mm, depending on the strain tested. The main objective of this study was to demonstrate the antagonistic effect of lactic acid bacteria on uropathogens, with the aim of identifying strains with the highest antimicrobial potential for future therapeutic or probiotic applications.