title: Phenotypic Assays to Determine Virulence Factors of Uropathogenic Escherichia coli (UPEC) Isolates and their Correlation with Antibiotic Resistance Pattern.
abstract: OBJECTIVE
  Urinary tract infection caused by uropathogenic Escherichia coli (UPEC) strains is one of the most important infections in the world. UPEC encode widespread virulence factors closely related with pathogenesis of the bacteria. The purpose of this study was to evaluate the presence of different phenotypic virulence markers in UPEC isolates and determine their correlation with antibiotic resistance pattern.
  
  
  METHODS
  UPEC isolates from patients with different clinical symptoms of UTI were collected and screened for biofilm and hemolysin production, mannose resistant, and mannose sensitive hemagglutination (MRHA and MSHA, respectively). In addition, antimicrobial resistance pattern and ESBL-producing isolates were recorded.
  
  
  RESULTS
  Of the 156 UPEC isolates, biofilm and hemolysin formation was seen in 133 (85.3%) and 53 (34%) isolates, respectively. Moreover, 98 (62.8%) and 58 (37.2%) isolates showed the presence of Types 1 fimbriae (MSHA) and P fimbriae (MRHA), respectively. Our results also showed a relationship between biofilm formation in UPEC isolated from acute cystitis patients and recurrent UTI cases. Occurrence of UTI was dramatically correlated with the patients' profiles. We observed that the difference in antimicrobial susceptibilities of the biofilm and nonbiofilm former isolates was statistically significant. The UPEC isolates showed the highest resistance to ampicillin, tetracycline, amoxicillin, and cotrimoxazole. Moreover, 26.9% of isolates were ESBL producers.
  
  
  CONCLUSIONS
  This study indicated that there is a relationship between the phenotypic virulence traits of the UPEC isolates, patients' profiles, and antibiotic resistance. Detection of the phenotypic virulence factors could help to improve understanding of pathogenesis of UPEC isolates and better medical intervention.
authors.affiliation: Department of Molecular Biology, Pasteur Institute of Iran, Tehran, Iran.
authors.forename: Mohsen
authors.initials: M
authors.lastname: Tabasi
authors.affiliation: Department of Molecular Biology, Pasteur Institute of Iran, Tehran, Iran.
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Asadi Karam
authors.affiliation: Department of Molecular Biology, Pasteur Institute of Iran, Tehran, Iran.
authors.forename: Mehri
authors.initials: M
authors.lastname: Habibi
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Mir Saeed
authors.initials: MS
authors.lastname: Yekaninejad
authors.affiliation: Department of Molecular Biology, Pasteur Institute of Iran, Tehran, Iran.
authors.forename: Saeid
authors.initials: S
authors.lastname: Bouzari
keywords: antibiotic resistance; patients' profiles; phenotypic virulence traits; urinary tract infection; uropathogenic Escherichia coli