Abstract
Background and Objectives: The multi-drug transporter NorA contributes to Staphylococcus aureus resistance to flouroquinolon antibiotics by promoting their active extrusion from the cell. Recent studies demonstrated that plant alkaloids such as noscapine can enhance the antimicrobial activity of some antimicrobial against resistant strains. The aim of the present study was to investigate the synergistic effect of ofloxacin, and noscapine on Staphylococcus aureus isolatated from patients.
Method and Materials: Ninety five multi-drug resistant isolates of Staphylococcus aureus were obtained from the hospitalized patients and outpatients of three hospitals in Tehran, Iran. Of these 95 isolates, 49 isolates were highly resistant to several antibiotics including ofloxacin. Serial dilution method was performed to determine minimum inhibitory concentration (MIC) of ofloxacin alone, noscapine alone and combination of the two agents.
Results: The results showed that MICs of ofloxacin were 16 µg/ml on 20 isolates, 32 µg/ml on 21 isolates and 64 µg/ml on 8 isolates. MIC of noscapine was between 0.5 µM/ml and 1.0 µM/ml. Combination of ofloxacin and noscapin leads to 2-4 times increase in MIC of ofloxacin.
Conclusions: Noscapine diminished the antimicrobial activity of ofloxacin on Staphylococcus aurous.