Occurrence and characterisation of uropathogenic Escherichia coli in urinary tract infections.

PURPOSE To study the occurrence of Uropathogenic Escherichia coli (UPEC) in cases with urinary tract infections. METHODS A total of 220 cases from urinary tract infections and 50 stool samples from apparently healthy individuals were included. The colonies identified as Escherichia coli were screened for virulence factors namely haemolysin, Mannose Resistant and Mannose Sensitive Haemagglutination (MRHA, MSHA), Cell surface hydrophobicity and Serum resistance by recommended methods. RESULTS Among 220 cases 91(41.36%) were haemolytic, 68(30.9%) showed MRHA, 58(26.36%) were cell surface hydrophobicity positive and 72(32.72%) were serum resistant. In 50 controls 3(6%) were haemolytic, 6(12%) showed MRHA, 9(18%) showed cell surface hydrophobicity and 12(24%) were serum resistant. The difference between cases and controls for haemolysis and MRHA were significant (p< 0.001 and p< 0.01 respectively). A total of 14 atypical Escherichia coli were isolated from urine and all showed the presence of one or the other virulence markers. Out of 18 mucoid Escherichia coli isolated 10 were serum resistant. Interestingly among the 15 Escherichia coli isolated from patients with pyelonephritis 8 were UPEC. CONCLUSIONS Out of 220 urinary isolates, 151 could be labelled as UPEC.