The etiological structure of urinary tract infections (UTI) is determined by the leading role of uropathogenic Escherichia coli (UPEC).
The aim of the work is to study the biological properties and phylogenetic diversity of E. coli strains isolated from UTI in outpatient and inpatient patients.
Methods and materials. 198 clinical UPEC strains were studied, 105 of which were designated as polyclinic and 93 as nosocomial (73 are isolated from urine and 20 are from catheter surface 48 hours after hospitalization). UPEC phylogenetic groups were determined by polymerase chain reaction (quadruplex PCR) according to O. Clermont et al. (2013).
Results. Among polyclinic cultures, representatives of all eight recognizable phylogroups were found; strains of UPEC phylogroup B2 (37.1%), E (13.3%) and F (8.6%) were most often found. Nosocomial cultures in almost 90% of cases belonged to the phylogroup B2, to which all the catheter-associated strains were assigned. The E. coli of the phylogroup B2, both in the mono-species and in the polymicrobial associations, was authentically more often isolated in the hospital than in the polyclinic (p<0.00001), whereas the bacteria of the phylogroup E, on the contrary, in the polyclinic (p<0.0001) . The hemolytic activity and biofilm-forming ability of UPEC strains did not differ in the two groups, while in the hospital hemolytic E. coli of the B2 phylogroup was significantly more likely than the polyclinic (p<0.001). In addition, B2 strainsformed biofilms in more than 60% cases. Regardless of the source of isolation, the strains were resistant to ampicillin (62.1%), amoxicillin/clavulanate (27.8%), cefotaxime (37.9%) and ciprofloxacin (36.9%). The production of ESBL was detected in fifty-one (25.8%) cultures, with a statistically significant difference in nosocomial strains: urinary Conclusions. The decrease in the sensitivity of community-acquired UPEC to beta-lactam antibiotics promotes the «convergence of the resistance phenotypes» in polyclinic and inpatient cultures. In the hospital under conditions of an immunocompromised host it is possible to concentrate E. coli B2 with a high virulent potential.

Keywords: B2 phylogroup, uropathogenic Escherichia coli (UPEC), quadruplex Clermont PCR, biofilm, antibiotic sensitivity