Effect of Osmolarity on Virulence of Uropathogenic Pseudomonas Aeruginosa

In the milieu of urinary tract, urine is subject to changes in osmolarity depending on host’s diet and clinical condition. The present investigation was planned to study the effect of osmolarity on growth and elaboration of virulence factors by Pseudomonas aeruginosa in planktonic and biofilm cell mode. Significant enhancement in growth and elaboration of all the virulence traits was observed with increase in osmolarity of the growth medium from 100 to 300 mOsmol/l. However, with further increase in osmolarity to 350 mOsmol/l there was significant decrease in growth and production of all the virulence determinants. In addition, organisms grown in 300 mOsmol/l medium showed increased adherence to uroepithelial cells, evade phagocytosis and were more virulent in mouse model of ascending pyelonephritis as indicated by higher bacterial load and tissue damage. The findings of the present study may be relevant for the better understanding of host-parasite interactions and will pave the way for the future development of preventive strategies against urinary tract infections.