مقالات پذیرفته شده در سومین کنگره بین المللی زیست پزشکی
Evaluation of distribution of virulence factors within Escherichia coli strains isolated from patients with acute and recurrent urinary tract infection
Evaluation of distribution of virulence factors within Escherichia coli strains isolated from patients with acute and recurrent urinary tract infection
Moein Saleh,1Amin Abd,2Hoora Mazaheri,3Mahboobeh Emadi,4Elham Khosravi,5Mohammad Pooya,6,*
1. Biology Department, Islamic Azad University, Tehran North Branch 2. Biology Department, Islamic Azad University, Science and Research Branch 3. Department of Medical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur, Malaysia 4. Biology Department, Islamic Azad University, Tehran North Branch 5. Biology Department, Islamic Azad University, Tehran North Branch 6. Molecular Biology Department, Pasteur Institute of Iran
Introduction: Urinary tract infection (UTI) is the second common bacterial infection worldwide. Either in its acute or recurrent phases, uropathogenic Escherichia coli (UPEC) is the main causative bacteria. However, the virulence factors (e.g. biofilmrelated ones) may vary in different phases, based on their needed functions.
The aim of this study was to evaluate the UPEC isolates recovered from acute and recurrent phases of urinary tract infection in the same patients, and to investigate their virulence factors.
Methods: The urine samples of out-/in-patients suffering from UTI in Loghman Hakim and Imam Khomeini hospitals were collected and they were under supervision for any probable recurrenceduring 1 year. Then, isolates were collected from urine samples and subjected for different cultures to select the E. coli isolates, and virulence factors test such as microtiter for detecting different biofilm forming unit was defined. Other virulence factors such as iron-related factors were evaluated by polymerase chain reaction (PCR).
Results: SixtyE. coli isolates were recovered from the urine samples of 30 patients (16 female, 14 male) which had both acute and recurrent phases of UTI. All of the isolates formed biofilmmostly weakly (55%), followed by moderate(28.3%) and strong (16.6%) biofilms. Strong biofilm was significantly more common in recurrent UTI than acute phase, and in females than males.Among the genes involved in biofilm formation, the luxS gene was observed in all of the isolates, followed by the fimA gene (96.6%).Also among the genes involved in iron transfer, the fyuA and hma genes were the most prevalent (93.3% and 91.6%, respectively). The Ag43 gene was significantly higher in the strong biofilm group than other groups.In contrast, the prevalence of the rpoS gene in this group was lower than others. Moreover, the isolates belonging tothe strong biofilm group had significantly lower percentage of iha than other iron transfer genes.
Conclusion: It seems that to cause UTI in recurrent phase as well as in women,uropathogens like UPECs need stronger biofilm formation ability. This might be related not only to some specific biofilm genes, but also to some virulence genes such as specified iron transfer genes.