YnfA , a SMR family efflux pump is abundant in Escherichia coli isolates from urinary infection.

A quantitative study was undertaken to determine the expression level of different effl ux pumps in multi-drug-resistant (MDR) Escherichia coli isolates from urinary infection. We have determined the presence of different effl ux pumps and measured the expression level of tolC, mdfA, norE and ynfA genes among 48 isolates by quantitative real-time PCR. The expression level of tolC and ynfA was constantly high and observed among 75-80% of isolates, whereas mdfA and norE were expressed occasionally. Our fi ndings suggest that ynfA, a new SMR effl ux pump gene family member increases the antibiotics’ resistance in E. coli.