Multidrug resistance (MDR) strains of Acinetobacter baumannii have been declared as a significant threat worldwide by World Health Organization (WHO). Researchers have shown that the prevalence of MDR strains of A. baumannii has reached an alarming rate all over the world. Among various assumed antibiotic resistance mechanisms of this bacterium, efflux pumps are regarded as one of the most important types. In this study, 100 clinical isolates of A.baumannii isolated from patients hospitalized in Intensive Care Unit (ICU); after biochemical and microbiological tests, the antibiotic sensitivity test was performed and determined the Minimum Inhibitory Concentration (MIC),then genes expression of selected Major facilitator superfamily (MFS) transporters were evaluated in presence of antibiotics. Results showed that the abaye genes of (002647, 1603) there were 100% in Acinetobacter baumannii isolates, percentage of abaye genes of (2281468, 1582001) were 88%, and percentage of abaye genes of (3671432, 3641859) were 0. The expression rate of abaye genes (3671432, 3641859, and 1603) in presence of all antibioticswere0.The expression rate of abaye2281468 in presence of ciprofloxacin antibiotic was 75%. This study revealed that MFS transporter of abaye2281468 unlike other MFS transporter of A.baumannii has an expression in presence of ciprofloxacin comparison with the fact that such phenomenon did not happen without presence of this antibiotic which can indicate the role of this MFS transporter in resistance to ciprofloxacin. Of course to evaluate the expression of these genes other molecular methods such as cloning and Real Time PCR should be used.
