• Evaluation of relationship between antibiotic resistance patterns and different types of grouping in Escherichia coli isolates recovered from patients with urinary tract infection in acute and recurrent phases
  • Amin Abd ,1,* Moein Saleh ,2 Hoora Mazaheri ,3 Mahboobeh Emadi,4 Elham Khosravi,5 Mohammad Pooya,6
    1. Biology Department, Islamic Azad University, Science and Research Branch
    2. Biology Department, Islamic Azad university , Tehran North Branch
    3. Department of Medical Engineering, Faculty of Engineering, University of Malaya
    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 most common nosocomial infection worldwide, and uropathogenic Escherichia coli (UPEC) are its main causative bacteria. Multi-drug resistant uropathogens such as UPEC has become a great concern during recent years. However, their patterns may vary depends on the episode of UTI (acute or recurrent). This study was conducted to evaluate the phylo- and serogroups, as well as antibiotic resistance pattern of UPEC isolates recovered in acute and recurrent phases of UTI in two referral hospitals in Tehran.
  • Methods: The urine samples of patients suffering from UTI in Loghman Hakim and Imam Khomeini hospitals were collected and they were under supervision for any probable recurrence during 1 year. Isolates were subjected for differential cultures to select the E. coli isolates. Then, antibiotic susceptibility test was performed using disc diffusion method. Phylo- and sero-grouping were performed according to the latest protocols, detecting related genes using PCR technique.
  • Results: Sixty isolates were recovered from acute and recurrent phases of UTI in 30 patients (16 relapse, 14 re-infection). Only O25 and O15 serogroups were detected with the frequency of 75% and 25% respectively, while 80% of O15 serogroup was detected in females and in-patients. Moreover, while the frequency of O15 serogroup was significantly higher in recurrent UTI, especially in re-infection, O25 serogroup was mostly detected in acute phase. Considering phylo-grouping, B2 group was the most frequent one (56.7%), followed by others. However, when other groups were detected more in females and in-patients, D was the only phylogroup which was detected more in males and out-patients, and along with F group were significantly detected more in acute UTI. All the isolates were sensitive to imipenem and nitrofurantoin. They were mostly resistant to cefazolin, trimethoprim-sulfamethoxazole, ciprofloxacin, and cefotaxime (60%, 56.7%, 55%, and 50% respectively). As expected, the resistance rate to the antibiotics was significantly higher among in-patients. Meanwhile, comparing two genders, the resistance rate to most of the antibiotics was similar, except to ceftazidime and gentamicin. The resistance rate to some antibiotics such as ceftazidime, cefotaxime and ampicillin was also significantly higher in relapse than re-infection. The sul1 has the highest frequency between the resistance genes (78.3%). As the antibiotic resistance pattern itself, the resistance genes were seen more among in-patients. However, the frequency of the genes was similar in both phases of UTI. The resistant isolates to all of the antibiotics were significantly mostly belonged to O25 serogroup and B2 phylogroup. Meanwhile, the isolates of phylogroup D were mainly resistant to the most of antibiotics.
  • Conclusion: It seems that the pattern of phylo- and sero-groups as well as antibiotic resistance in UPEC isolates might be different in different phases of UTI, and they represent a more virulent and more resistant characteristics in acute UTI. Moreover, the isolates which are more resistant mainly belong to the phylo- or sero-groups participate more in the pathogenesis of UTI.
  • Keywords: Urinary tract infection, uropathogenic Escherichia coli