An integrative approach to assessing the pathogenic potential of <i>Escherichia coli</i> strains isolated from urine

Abstract

Introduction. Uropathogenic Escherichia coli (UPEC) are characterized by the ability to survive and reproduce in the urinary tract due to the presence of specific virulence factors. In routine laboratory practice, the detection of diagnostically significant bacteriuria does not provide an idea of the level of infection of the urinary system (renal parenchyma, bladder), the pathogenic potential of the strain in the progression and chronicity of the infectious process, and the occurrence of life-threatening conditions (urosepsis, meningitis).
 Objective. To characterize the population structure, genetic diversity and pathogenic potential of E. coli strains isolated from urine.
 Materials and methods. 194 strains of E. coli isolated from urine were studied. Detection of 17 genes encoding the synthesis of: adhesins (pap, fimH, sfa, focG, afa), toxins (hlyA, cvaC, cnf, cdtB), capsular antigens (kpsMTII, kpsMTIII, kpsMT K1), siderophores (fyuA, iutA), invasins (ibeA), genetic markers of the pathogenicity island (PAI) of UPEC CFT073, the gene (traT) encoding serum resistance capacity and phylogenetic groups were performed by PCR (CXT-1000, BioRad, USA) with published primers (Synthol, Sibenzyme, Evrogen, Russia). To assess the statistical significance of differences, Fisher's exact test was used. Differences were considered significant at a confidence interval of 95% (p 0.05).
 Results. E. coli strains more often (p 0.05) belonged to the phylogenetic group B2 (57.7%). Pathogenetically significant virulence determinants were identified in 97.9% of strains. Based on the combination of 17 genes, 134 individual virulence genotypes were identified. In 93.3% of strains, a genetic predisposition to the occurrence of recurrent urinary tract infections (UTIs) was revealed, in 6.9% there was a potential for the development of pyelonephritis and recurrent cystitis. Markers of life-threatening complications of UTI were identified in 12% of strains, of which 10.7% were the development of urosepsis and 1.3% were meningitis.
 Conclusion. Detection of a complex of genes in E. coli strains isolated from urine confirms the etiological significance of the isolate and allows one to assess the pathogenic potential for the development of chronic and severe life-threatening complications.