eng Oriental Scientific Publishing Company Biomedical and Pharmacology Journal 0974-6242 2015-03-15 8 March Spl Edition 91 97 2346 article Reza Ranjbar 1 Mehdi Moazzami Goudarzi 2 Nematollah Jounaidi 3 Molecular biology research center, Baqiyatallah University of medical science, Tehran, Iran. Department of Microbiology, Boroujerd Branch, Islamic Azad University, Boroujerd, Iran. Health Research Center, Baqiyatallah University of medical science, Tehran, Iran The present study aims to evaluate the effects of lactobacillus by-products on pyelonephritis-associated pili pap  expression in Escherichia (E.) coli. Vaginal lactobacillus rhamnosus and lactobacillus crispatus species were isolated and the effects of their culture supernatants (CS) on pap promoter activity in uropathogenic E. coli (UPEC) were studied. A new reporter construct of pET28a including Iranian firefly luciferase coding sequence was used to assess the pap propotor activity. The lactobacillus rhamnosus  forced the  pap promoter  to turn off when UPEC was exposed to 1%, 1.1%, and 1.3% of the culture supernatant. In addition, lactobacillus crispatus could continuously switch off pap promoter phase variations when UPEC was exposed to a serial dilution of culture supernatant. The findings showed therapeutic and preventive potential of   lactobacillus rhamnosus and lactobacillus crispatus for bacterial vaginitis and urinary tract infection (UTI) through controlling the virulence factors expression via their ecological origins. https://biomedpharmajournal.org/vol8marchspledition/vaginal-lactobacilli-and-pap-operon-expression-in-uropathogenic-escherichia-coli/ Escherichia coli  Vaginitis Urinary Tract Infection  lactobacillus rhamnosus  lactobacillus crispatus