Investigation for Lactobacillus Acidophilus Supernatant’s Effects on Type I Fimbriae Promoter Activity in O26 Serotype of UPEC Strain of Escherichia Coli

Abstract

Background & Objectives: Type I fimbriae is one of the major key factors in attachment and colonization of Escherichia coli in the urinary tract. fim operon phase variation is controlled by various environmental situations. The goal of this study is to investigate of the effect of lactobacillus acidophilus culture supernatant (Cs) on fim phase variation. Material and Methods: In this study, at first, lactobacillus acidophilus culture supernatant (CS) was prepared from overnight culture. Then modified M9 medium which included serial dilution of Cs (0.1% up to 6%) was prepared. Then UPEC isolate (o26) was inoculated in modified M9. Finally, Fim promoter activity was assessed through fim promoter PCR product digestion by HinfI restriction enzyme. Results: Modified M9 medium including 0.1% up to 0.7% of Cs, supports and stimulates fim operon expression. But modified M9 including 0.8% up to 3% of Cs, downregulated fim expression. By the way, UPEC was not able to multiply during inoculation in modified M9 including 4% up to 6% of Cs. Conclusion: Probably, Lactobacillus acidophilus secrets some by-products which are able to inhibit fim operon expression in UPEC. Characterization and pharmaceutical application of these metabolites may be easily lead to design the new therapeutic products for prevention of urinary tract infections, especially in women.