Assessment of phylogeny, virulence genes and O serogroup profiles in Escherichia coli from uncomplicated and complicated cystitis and from asymptomatic bacteriuria

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Purpose: There have been only a few studies to clarify the genetic characteristics of microorganisms isolated from complicated urinary tract infection (UTI) and asymptomatic bacteriuria (ASB). In the present study, we determined prevalence of phylogenetic groups, O serotypes, and virulence factor (VF) genes, in E. coli isolates from umcomplicated cystitis (UC), complicated cystitis (CC), and complicated asymptomatic bacteriuria (CASB).Materials and Methods: Three hundred and forty seven E.coli isolates (204 from UC, 66 from CC, and 77 from CASB) were collected. Polymerase chain reaction (PCR) assays were conducted for phylogenetic analysis and detection of 18 VF genes (aer, afa, cnfl, cvaC, ETTT, fimH, fyuA, hly, ibeA, iha, iroN, kpsMT, ompT, PAI, pap, sfa/foc, traT and usp). Further, the isolates were subjected to O serotyping.Results: Phylogenetic group B2 was shown to be predominant in all categories (UC: 71 %, CC: 73%, and CSAB: 61 %). There was no significant difference in distribution of common uropathogenic O serotypes among the three categories. (UC: 59 %, CC: 50%, and CSAB: 46 %). Of 18 virulence genes examined, iroN, pap, ompT, and PAI were more frequently discovered in UC than in CC or CSAB, whereas the prevalence of other 14 genes were similar among the three categories.Conclusions: E. coli isolates from CC and CASB shared almost similar characters and properties with UC isolates in terms of phylogenetic, O serotypes, and VFs, although it is likely that more number of VFs are requird in causing uncomplicated or symptomatic UTI than complicated or asymptomatic infections. The development of symptomatic infection may be more closely associated with variation of the host environment rather than with VFs expressed by microorganism.