Detecting Efflux Pumps Genes in the Fluoroquinolones Resistant and Sensitive Strains of Escherichia coli in Patients with Urinary Tract Infection in Qom, Iran

Efflux pumps are among the main mechanisms for antibiotic resistance in Escherichia coli (E.coli) strains. The present study aimed to investigate the relationship between 5 efflux pump genes; acrA, acrB, emrA, emrB, and mdtk and fluoroquinolone resistance in E.coli isolated from patients with urinary tract infections.

In this descriptive cross-sectional study, clinical samples were collected from several medical centers in Qom City, Iran, from June 2017 to September 2017. After the detection and primary identification of E.coli isolations using culture and biochemical tests, the antimicrobial susceptibility strains to the fluoroquinolones, such as Ciprofloxacin, Norfloxacin, Ofloxacin, and Levofloxacin were determined by disk diffusion method according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. Identifying the genes encoding efflux pumps was performed in sensitive and resistant strains by Polymerase Chain Reaction (PCR) technique.

Of the collected 170 clinical samples, 100 strains of E.coli were isolated and identified based on phenotypic characteristics. Evaluating antibiotic susceptibility of the strains demonstrated that 63(63%) isolates presented resistance to fluoroquinolones. PCR assay demonstrated that the prevalence of acr- AB, emrAB, and mdtk genes among fluoroquinolones resistant isolates were equal to 100%, 98%, and 94%, respectively. Furthermore, the frequency of the mentioned genes in fluoroquinolone-sensitive isolates was measured to be 34.2%, 27.02%, and 13.5%, respectively.

The present research results revealed that the presence of acrAB, emrAB, and mdtk efflux pumps genes is potentially a factor in resistance to fluoroquinolone antibiotics. The presence of these genes in sensitive strains may indicate that the genes are not transcribed or translated. According to the high resistance of E.coli strains to fluoroquinolone antibiotics, it is recommended that antibiotic susceptibility testing be performed before starting treatment.