Uropathogenic Escherichia coli causing urinary tract infections

Background & objectives: The information on the characteristics of Escherichia coli causing urinary tract infections is limited. We have characterised the urovirulence factors of Esch. coli isolated from symptomatic patients of urinary tract infections (UTI) in order to determine their pathogenic potential and the antibiotic sensitivity profile. Methods: Semi-quantitative urine culture was done on 370 symptomatic patients suffering from urinary tract infections. Phenotypic characterization of the urovirulence factors of Esch. coli was undertaken and the antibiotic susceptibility was determined. Results: Esch. coli was responsible for 45.5 per cent of infections. Resistance to amoxycillin, cotrimoxazole, nalidixic acid, norfloxacin and ciprofloxacin among Esch. coli isolates ranged from 70-95 per cent. Serotype 0101 was found to be the commonest serotype (7/26). The virulence factors associated with uropathogenic Esch. coli were haemolysin production (5/30), presence of mannose resistant P-fimbriae (5/30), presence of mannose sensitive type I fimbriae (6/30) and the presence of mannose resistant F-fimbriae (2/30). Siderophores production was seen in all the isolates causing UTI. Interpretation & conclusion: Esch. coli was found to be the commonest cause of UTI in our study population. Antibiotic resistance was high among the strains circulating which emphasises the need for judicious use of antibiotics. Certain virulence factors like haemolysin production and presence of fimbriae in the Esch. coli may be associated with the urovirulence.