VIRULENCE FACTORS AND ANTIMICROBIAL RESISTANCE IN UROPATHOGENIC ESCHERICHIA COLI STRAINS ISOLATED FROM CYSTITIS AND PYELONEPHRITIS

Background and Aim:The aim of this study was to investigate the prevalence of virulence genes as well as patterns of antibiotic resistance and Extended-Spectrum β-Lactamase (ESBL) production in cystitis and pyelonephritis UPEC isolates.Methods:200 UPEC isolates were collected from hospitalized patients with pyelonephritis (n=50) and cystitis (n=150) in Shafa Hospital, Iran between September 2014 and February 2015. Antimicrobial susceptibility and ESBL production was determined with confirmatory tests. Polymerase Chain Reaction (PCR) assay was performed in order to determine the prevalence of virulence genes including fimH, papC and hly in UPEC strains.Results:Of a total 200 UPEC isolates, the highest and lowest resistance rates to antibiotics were for Cefalexine (74%) and Nitrofurantoine (9%), respectively. Of these isolates, 72 (36%) and 128 (64%) strains were ESBL-positive and ESBL-negative, respectively. Virulence genes studied in this research were found in 104 (52%) isolates. The frequency of virulence genes fimH, papC and hly were 64%, 38% and 12% respectively. The most commonly identified virulence gene in ESBL and non-ESBL producing strains was fimH 46 (23%) and 86 (43%), respectively. The hlyA gene was more prevalent among patients with pyelonephritis than cystitis.Conclusion:The frequency of studied virulence genes was not significantly different between pyelonephritis and cystitis UPEC strains, but the prevalence rates of hlyA and papC genes were higher among UPEC strains isolated from inpatients compared to outpatients; hence, they could be considered as useful targets for prophylactic interventions.

کلیدواژه ها:

Urinary tract infections ، Escherichia coli ، Extended spectrum β-lactamase ، Virulence genes ، Pyelonephritis ، Cystitis