Uropathogenic Escherichia coli in Iran: Serogroup distributions, virulence factors and antimicrobial resistance properties

Hassan Momtaz,Reza Ranjbar,Azam Karimian,Negar Souod,Farhad Safarpoor Dehkordi,Mahboobeh Madani,Meysam Sarshar

doi:10.1186/1476-0711-12-8

Abstract

BackgroundUrinary tract infections (UTIs) are one of the most common bacterial infections with global expansion. These infections are predominantly caused by uropathogenic Escherichia coli (UPEC).MethodsTotally, 123 strains of Escherichia coli isolated from UTIs patients, using bacterial culture method were subjected to polymerase chain reactions for detection of various O- serogroups, some urovirulence factors, antibiotic resistance genes and resistance to 13 different antibiotics.ResultsAccording to data, the distribution of O1, O2, O6, O7 and O16 serogroups were 2.43%, besides O22, O75 and O83 serogroups were 1.62%. Furthermore, the distribution of O4, O8, O15, O21 and O25 serogroups were 5.69%, 3.25%, 21.13%, 4.06% and 26.01%, respectively. Overall, the fim virulence gene had the highest (86.17%) while the usp virulence gene had the lowest distributions of virulence genes in UPEC strains isolated from UTIs patients. The vat and sen virulence genes were not detected in any UPEC strains. Totally, aadA1 (52.84%), and qnr (46.34%) were the most prevalent antibiotic resistance genes while the distribution of cat1 (15.44%), cmlA (15.44%) and dfrA1 (21.95%) were the least. Resistance to penicillin (100%) and tetracycline (73.98%) had the highest while resistance to nitrofurantoin (5.69%) and trimethoprim (16.26%) had the lowest frequencies.ConclusionsThis study indicated that the UPEC strains which harbored the high numbers of virulence and antibiotic resistance genes had the high ability to cause diseases that are resistant to most antibiotics. In the current situation, it seems that the administration of penicillin and tetracycline for the treatment of UTIs is vain.

Highlights

Urinary tract infections (UTIs) are one of the most common bacterial infections with global expansion
Our results revealed high distribution of uropathogenic Escherichia coli (UPEC) serogroups isolated from patients with urinary tract infection (Table 4)
Based on our results, O25 serotype, fim virulence gene, aadA1 antibiotic resistance gene and resistance to penicillin had highest frequencies in UPEC strains isolated from UTIs patients

Summary

Introduction

Urinary tract infections (UTIs) are one of the most common bacterial infections with global expansion. These infections are predominantly caused by uropathogenic Escherichia coli (UPEC). Uropathogenic E. coli (UPEC) strains have shown certain virulent properties, including iron uptake systems, adhesins, specific O: K: H serotypes and synthesis of cytotoxins. All of these properties contribute to colonization and invasion of the bacterium [6]. The successful colonization of UPEC in the urinary tract depends on the expression of fimbrial adhesion proteins, which facilitate attachment of the bacterium to the urothelium, and on the presence of specific bacterial genes that encode virulence factors [7,8,9]

Methods

Results

Conclusion