Determination of icaD gene expression level in Staphylococcus aureus by treatment with garlic extract and rifampin

In this research, antibiogram, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) tests were conducted with specific concentrations of rifampin antibiotic and garlic extract (garlic tablet). Biofilm phenotypic test was performed with 96 wells microplate and with different concentrations of rifampin and garlic. Following the extraction of RNA from rifampin and garlic-affected specimens, as well as control, cDNA synthesis and then real time PCR were performed and the icaD gene expression level was measured in the samples. The results of MIC and MBC under rifampin treatment and the combination of garlic and rifampin for all strains were 375 and 750 μg/ml, respectively. Based on Real time PCR results, icaD gene expression was influenced by garlic extract and rifampin, and decreased significantly in the strains. In addition, the rifampin composition and garlic extract resulted in a further reduction in the expression of this gene. Garlic extract and rifampin in the standard strain reduced the icaD expression to 38% and 56%, respectively and the combination of rifampin and garlic extract led to a reduction of 67% of the icaD biofilm gene expression.