Effect of galbanic acid, a sesquiterpene coumarin from Ferula szowitsiana, as an inhibitor of efflux mechanism in resistant clinical isolates of Staphylococcus aureus

Brazilian Journal of Microbiology

Bibi Sedigheh Fazly Bazzaz²  Zahra Memariani¹  Zahra Khashiarmanesh¹  Mehrdad Iranshahi²  Mahbobeh Naderinasab¹ 

[1] ,Mashhad University of Medical Sciences Biotechnology Research Center and School of Pharmacy Mashhad,Iran

关键词: Efflux pump inhibitor;    Ferula szowitsiana;    Galbanic acid;    Staphylococcus aureus;   

DOI  :  10.1590/S1517-83822010000300006

来源: SciELO

【 摘 要 】

Galbanic acid, a sesquiterpene coumarin from Ferula szowitsiana roots, was investigated for its potentiating effect on the antimicrobial activity of antibiotics as well as ethidium bromide, in 6 multidrug resistance (MDR) clinical isolates of Staphylococcus aureus. Galbanic acid had inhibitory effect on none of the isolated bacteria tested (up to 800 µg /ml). The MIC range of ciprofloxacin, tetracycline and ethidium bromide, against all tested S. aureus were 10-80, 10-80 and 4-16 µg/ml, respectively. These were reduced to ≤2.5-5, 2.5-5 and 0.5-2 µg/ml in the presence of galbanic acid (300 µg /ml) or verapamil (100 µg /ml). The rate of ethidium bromide (2 µg /ml) accumulation in clinical isolates was enhanced with galbanic acid (300 µg /ml). There is also a decrease in loss of ethidium bromide from bacteria in the presence of galbanic acid. Similar results were obtained when verapamil (100 µg /ml) was used as an efflux pump inhibitor. Galbanic acid, like verapamil, a typical inhibitor of efflux pump, reduced the MIC of ethidium bromide and tested antibiotics. Since efflux is the only known reported mechanism for ethidium bromide resistance, the reduction in ethidium bromide MIC and enhanced accumulation as well as decreased efflux of ethidium bromide in the presence of galbanic acid, can be attributed to this efflux inhibitory properties.

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