The comparison between virulence factors of Escherichia coli isolated from urinary tract infections and feacal flora

Abstract

Urinary tract infections (UTIs) are significant health problem, with Escherichia coli as the primary pathogen in proximally 80% of cases. The adhesion of E coli to the host cell can be influenced by cell surface hydrophobicity (CSH) and is an important factor for the development of infections. This study was conducted to find the relation between CSH and one of the adhesions (mannose resistant haemagglutin, MRHA) and a virulence factor (haemolysin), in the bacterial isolates from UTIs and comparison of the UTI isolates with normal faecal flora. The results showed a significant difference in the expression of MRHA in the UTIs compared to that of faecal flora (48% and 12%, respectively, P = 0.012). CSH was determined by two methods of salt aggregation test and bacterial adhesion to hydrocarbons. The results of these tests were correlative and UTIs isolates were found to be more hydrophobic than the normal faecal flora, while the standard strains of enterohaemorrhagic E coli were more hydrophobic than the normal faecal flora. Hemolysin production was higher in the isolates from UTI (28% in UTIs compared to 6% in faecal flora P = 0.0035). In conclusion, we found that the pathogenic E. coli express more MRHA, are more hemolytic and have a higher cell surface hydrophobicity which may help them to start an infection.