Determination of phenotypic expression of the fimbriae and hemolysin of uropathogenic Escherichia coli (UPEC)

Background: The bacterial strains that cause symptomatic urinary tract infections possess diverse distinctive properties that enable them to overcome the local host defences. In Escherichia coli, virulence results from the cumulative impact of several virulence factors, which can vary according to the patient populations. The study was undertaken to assess the prevalence of the virulence factors by phenotypic assays in the E. coli isolates which were isolated from patients with UTI from a tertiary care hospital in Kerala. Methods: A total of 300 E. coli isolates were obtained from symptomatic cases of urinary tract infections and 30 E. coli faecal isolates were obtained from apparently healthy individuals and they were tested for phenotypic properties like haemolysin production, mannose resistant hemagglutination to indicate P fimbriae, cell surface hydrophobicity. Results: Among the 300 E. coli isolates from the cases group, 135 (43.5%) were hemolytic, 106 (35.5%) were MRHA positive, 123 (41%) were hydrophobic. Among the 30 controls, 2 (6%) were hemolytic, 02 (6%) were MRHA positive and 04 (10%) were hydrophobic. The difference between the cases and the control group was significant (P < 0.001). Multiple virulence factors were observed in 51% of the isolates. Conclusion: The present study showed varied phenotypic expression of the virulence factors in the urinary isolates as compared to the fecal isolates.