title: Genotypic Characterization of Virulence Factors inEscherichia coliIsolated from Patients with Acute Cystitis, Pyelonephritis and Asymptomatic Bacteriuria.
abstract: BACKGROUND
  Urinary Tract Infections (UTIs) caused by UropathogenicEscherichia coli(UPEC) are among the most common infections worldwide. It is well-documented that the pathogenesis of UPEC is mediated by the production of a wide variety of Virulence Factors (VFs). Thus, detection of these VFs and evaluation of their association with different clinical types of UTIs could help to understand the role of these factors in pathogenesis of UPEC isolates.
  
  
  OBJECTIVE
  To investigate the genotypic characteristics of UPEC isolates and to examine the relationship between VFs and different clinical symptoms of UTI.
  
  
  METHODS
  In this cross-sectional study conducted at Pasteur Institute of Iran, a total of 156 UPEC isolated from outpatients and inpatients (symptomatic and asymptomatic UTI patients) visiting general and private hospitals in Tehran, Iran between March 2014 and February 2015 were included. Among them, 49 patients experienced at least one episode of recurrent UTI. A Polymerase Chain Reaction (PCR) assay was developed to detect the presence of different VFs in the isolates. Moreover, Pulsed-Field Gel Electrophoresis (PFGE) was used to characterize clonal relationships among UPEC isolates.
  
  
  RESULTS
  The prevalence of virulence genes ranged from 0% forcdtBto 100% forfimH. ThepapEF, hlyAandaergenes were found to be significantly more frequent in UPEC isolated from patients with pyelonephritis, while theafagene, the only indicator of recurrent UTIs, was more prevalent in UPEC isolated from patients with cystitis. In the present study, 34 PFGE clonal groups were found in the UPEC genome.
  
  
  CONCLUSIONS
  Our findings showed that from outpatients and patients with pyelonephritis, isolates were more virulent than those isolated from inpatients and cystitis patients, respectively. PFGE displayed a large diversity in the UPEC isolates that could be considered as an evolutionary strategy in the survival of the bacteria.
authors.affiliation: Student, Department of Molecular Biology, Pasteur Institute of Iran , Pasteur Ave., Tehran-13164, Iran .
authors.forename: Mohsen
authors.initials: M
authors.lastname: Tabasi
authors.affiliation: Assistant Professor, Department of Molecular Biology, Pasteur Institute of Iran , Pasteur Ave., Tehran-13164, Iran .
authors.forename: Mohammad Reza Asadi
authors.initials: MR
authors.lastname: Karam
authors.affiliation: Assistant Professor, Department of Molecular Biology, Pasteur Institute of Iran , Pasteur Ave., Tehran-13164, Iran .
authors.forename: Mehri
authors.initials: M
authors.lastname: Habibi
authors.affiliation: Associate Professor, Department of Epidemiology, Pasteur Institute of Iran , Pasteur Ave., Tehran-13164, Iran .
authors.forename: Ehsan
authors.initials: E
authors.lastname: Mostafavi
authors.affiliation: Professor, Department of Molecular Biology, Pasteur Institute of Iran , Pasteur Ave., Tehran-13164, Iran .
authors.forename: Saeid
authors.initials: S
authors.lastname: Bouzari
keywords: Pulsed-field gel electrophoresis; Urinary tract infection; Uropathogenic Escherichia coli