In the present study we demonstrated a novel protective role of Pseudomonas aeruginosa PAO1
flagellin 'b' in prevention of
urinary tract infection (UTI). P. aeruginosa is motile via single polar flagellum made up of
polymerized flagellin proteins. It is a serious nosocomial pathogen causing UTIs. Predisposing factors include instrumentation and catheterization which enhance colonization with P. aeruginosa, leading to ascending
infection. Hence for a newer, safer and effective approach, the present study focussed on the prophylaxis using bacterial
flagellin, isolated and purified (PCR sequencing and MALDI-TOF) from P. aeruginosa PAO1 strain, which triggers immune response [both non-specific and specific (active and passive)] as defense against
infection. Administration of
flagellin 'b' via intraperitoneal route enhanced the clearance of homologous as well as heterologous bacteria (P. aeruginosa uroisolate carrying
flagellin 'a') in renal tissue, decreased the levels of
malondialdehyde (MDA) and reverted structural integrity of renal tissue to near normal in female LACA mice. Immunization suppressed the production of pro-inflammatory
cytokines [
interleukin-1β (IL-1β) and
tumor necrosis factor alpha (TNF-α)] and activated humoral immune response. Anti-
flagellin antibodies (quantified by ELISA) helped in the clearance of bacterial load by opsonophagocytosis. Adoptive transfer of
antisera also protected mice from PAO1 challenge, indicating protective role of
antibodies. In conclusion, this is the first report that describes
flagellin as a potential prophylactic agent which downregulates
inflammation and curbs UTIs.