Effect of trifolium cherleri extract on clinical specimens of ciprofloxacin-resistant staphylococcus aureus strain contain norb gene

Sana Mirzazadeh,1 Hassan noorbazargan,2 Fatemeh ashrafi,3,*

1. Department of Biology, North Tehran Branch, Islamic Azad University, Tehran, Iran
2. Department of Biotechnology, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
3. Department of Biology, North Tehran Branch, Islamic Azad University, Tehran, Iran



Staphylococcus aureus is one of the five common causes of infectious diseases, especially nosocomial infections infections. unfortunately, this bacterium is resistant to antibiotics, especially ciprofloxacin. one of the mechanisms of resistance of this bacterium to the ciprofloxacin antibiotic is the existence of an efflux pump. in this study, the existence of norb efflux pump gene, its gene expression and active efflux activity in iranian ciprofloxacin resistance s. aureus isolates.


In this experimental study, a total of 250 clinical samples were collected from different hospitals in tehran–iran. s. aureus isolates were identified and antibiotic resistance profile, detection norb gene and its gene expression using pcr and in addition to, efflux pump activity was determined by mic test.


Totally, 50 s. aureus isolates were recovered and the results of antibiotic susceptibility tests show that 34 out of 50 s. aureus isolates (68%) were resistant to methicillin and from the 34 mrsa, 12 isolates (24%) were resistant and none of the samples were resistant to vancomycin. moreover, all of the ciprofloxacin resistant strains harbored the norb gene and have active efflux pump. the results showed that different strains had a range of mics 31.25-500 µg/ml.


The results of this study showed correlation between ciprofloxacin resistance and norb efflux activity and its gene expression in ciprofloxacin resistance isolates.


Staphylococcus aureus, ciprofloxacin resistance, efflux pump, norb