Genetic relatedness of the Escherichia coli fecal population and strains causing urinary tract infection in the same host.

It is common knowledge that fecal microbiota is a primary source of Escherichia coli causing urinary tract infections (UTIs) via the fecal-perineal-urethral route. But, it is still unknown whether E. coli UTI is mainly caused by dominant fecal E. coli isolates (prevalence hypothesis) or the isolates that possess more virulence factors (special pathogenicity hypothesis). In the present study, the urine E. coli isolates of 30 women with UTI were compared with the fecal E. coli isolates of the same patients and healthy control individuals according to the phylogenetic group, virulence genotype, and antibiotic susceptibility pattern. The genetic relatedness of the isolates was specified and compared by pulsed-field gel electrophoresis (PFGE). PFGE analysis showed that most patients (73.3%) had distinct urine isolates which were not similar to any of their fecal isolates. Based on the phylogenetic analysis, most of the urine and fecal isolates of healthy women were assigned to phylogenetic group B2, followed by D. The distribution of phylogenetic groups was significantly different between the urine and the fecal isolates of patients (p < 0.05). The prevalence of fimH and ompT among urine isolates was significantly more than that among fecal isolates. The level of multidrug resistance was higher among urine isolates. Although more in-depth researches are required, the present study could be supported by pathogenicity hypothesis. Furthermore, concerning the antibiotic resistance pattern among uropathogenic E. coli should be highly considered.