Microbial Susceptibility, Virulence Factors, and Plasmid Profiles of Uropathogenic Escherichia coli Strains Isolated from Children in Jahrom, Iran

Background: Urinary tract infections (UTIs), including cystitis and pyelonephritis, are the most common infectious diseases in childhood. Escherichia coli (E. coli) accounts for as much as 90% of the community-acquired and 50% of nosocomial UTIs. Therefore, identification of E. coli strains is important for both clinical and epidemiological implications. Understanding antibiotic resistance patterns and molecular characterization of plasmids and other genetic elements is also epidemiologically useful. Methods: To characterize uropathogenic strains of E. coli, we studied 96 E. coli strains recovered from urine samples of children aged 1 month to 14 years with community-acquired UTIs in Jahrom, Iran. We assessed virulence factors (VFs), drug sensitivities, and plasmid profiles. Results: Drug sensitivities of the isolates were: 19.8% (ampicillin), 24% (trimethoprim-sulfamethoxazole), 29.2% ( tetracycline), 75.5% (nalidixic acid), 80.4% (cefixime), 84.6% (gentamicin), 91.4% (ciprofloxacin), 96.8% (nitrofurantoin), 96.8% (amikacin) and 100% (imipenem). Totally, 76 isolates harbored plasmids with an average of 5.5 plasmids (range: 1 - 10) in each strain. Plasmid profiling distinguished 22 different E. coli genotypes in all isolates that ranged in similarity from 50% to 100%. PCR showed that the prevalence of virulence genes ranged from 15.62% for hly to 30.2% for pap. Conclusion: These data mandate local monitoring of drug resistance and its consideration in empirical therapy of E. coli infections. Plasmid analysis of representative E. coli isolates also demonstrates the presence of a wide range of plasmid sizes, with no consistent relationship between plasmid profiles and resistance phenotypes. Plasmid profiles distinguished more strains than did the antimicrobial susceptibility pattern.