Study the expression of mar a gene in ciprofloxacin and tetracycline resistant mutants of esherichia coli

ABSTRACT

Mar A activates two membrane dependent mechanisms of resistance to different antibiotics, such as ciprofloxacin and tetracycline, including promotion of outflux and inhibition of influx of antibiotics. Thus, MarA causes multiple antibiotic resistance phenotype. The activation of these mechanisms needs overexpression of mar A. This could happen through mutation in marR. Thus, the aim of this study was to measure mar A expression in ciprofloxacin resistant E. coli gyrA mutants and clones with or without marR mutation. For this purpose, real time PCR was used to measure relative expression ofmarA in above mutants and clones. Results showed that two clones, C14 and C17 overexpressed mar A. It is concluded that the level of mar A expression is important for activation of above mechanisms