A Comparative Study of Clinical and Environmental Isolates of Pseudomonas aeruginosa in Terms of Quorum Sensing, Outer Membrane Proteins and Their Ability to Cause Urinary Tract Infection

Pseudomonas aeruginosa, one of the most common causes of nosocomial urinary tract infections, is widely distributed in environments. Environmental and clinical isolates have been compared on the basis of production of virulence factors and genomic diversity. However, no studies are available regarding the comparison of their physiological and morphological characteristics. 15 clinical and environmental isolates of Pseudomonas aeruginosa were screened for quorum sensing molecules and all were found to be producers of varied levels of acyl homoserine lactones (AHL’s). Both the isolates showed comparable biofilm forming ability but revealed different outer membrane protein profile. Clinical isolate was found to be more virulent than environmental isolate on the basis of urine and renal colonization in experimental urinary tract infection mouse model. Histopathology and other pathology index factors like myeloperoxidase (MPO), malondialdehyde (MDA) and reactive nitrogen intermediate (RNI) level were also found to be more in case of animals infected with clinical isolates. In conclusion, despite similar abilities of biofilm formation and production of quorum sensing signal molecules, clinical isolate was found to have selective advantage in establishing and causing pathology in the urinary tract of mice. Our results indicate that pathogenicity potential of Pseudomonas aeruginosa vary depending on the source of strain as well as its outer membrane protein profile.