Phenotypic study of virulence factors in Escherichia coli isolated from antenatal cases, catheterized patients, and faecal flora.

INTRODUCTION AND OBJECTIVE The bacterial strains that cause symptomatic urinary tract infections possess diverse distinctive properties that enable them to overcome the local host defenses. In Escherichia coli, virulence results from the cumulative impact of several virulence factors, which can vary according to the patient populations. Hence, a study was undertaken to assess the prevalence of the virulence factors in the E.coli isolates which were isolated from pregnant woman, catheterized patients and from the stool samples of healthy individuals. METHODS A total of 93 E.coli isolates were obtained from symptomatic cases of urinary tract infections and 31 E.coli faecal isolates were obtained from apparently healthy individuals and they were tested for haemolysin production, mannose resistant haemagglutination to indicate P fimbriae, cell surface hydrophobicity, and the gelatinase enzyme. RESULTS Among the 93 E.coli isolates from the cases group, 39(41.9%) were haemolytic, 38(40.9%) were MRHA positive, 29(31.2%) were hydrophobic and 18(19.4%) were positive for gelatinase. Among the 31 controls, 01(3.2%) were haemolytic, 02(6.5%) were MRHA positive and 03(9.7%) were hydrophobic and none of the isolates were positive for gelatinase. The difference between the cases and the control group was significant (P<0.001).Multiple virulence factors were observed in 10% of the isolates. INTERPRETATION AND CONCLUSIONS The present study showed that the expression of the virulence factors was more in the urinary isolates of the antenatal cases and in the catheterized patients as compared to the faecal isolates.