Abstract
Background: Acinetobacter baumannii is one of the Gram-negative bacteria in nosocomial infections that is resistant to treatment
and control. The isolation of these bacteria is increasing significantly throughout the world. With increasing populations and a
reduction in the use of synthetic drugs, many of these medicinal herbs are replacing other treatments.
Objectives: The present study aims to investigate the inhibitory effects of Satureja khuzestaniea essence on the expression of the antibiotic
resistance genes bla-OXA-23 and Housekeeping DNA gyrase-A in multidrug-resistant strains of Acinetobacter baumannii, using
the RT-PCR technique.
Methods: Satureja khuzestaniea essential oil was collected from the Barij essence research farm in May 2010. Fivemultidrug-resistant
strains of Acinetobacter baumanniithat contain the bla-OXA-23 and housekeeping DNA gyrase-A genes were selected. The disk diffusion
method was used to evaluate the antimicrobial effect of essential oil, and major components were used. The minimum inhibitory
concentration (MIC) values of the Satureja khuzestaniea essential oil were determined via a broth macro dilution assay, as recommended
by the CLSI. Finally, an analysis of the bla-OXA-23 and Housekeeping DNA gyrase-A was performed using the RT-PCR technique.
Results: The major components of Satureja khuzestaniea essence are carvacrol (90.88%), ρ-cymene (3.11%), γ terpinene (1.24%), and
linalool (0.91%). The RT-PCR technique demonstrates that Satureja khuzestaniea with an MIC of 0.2 µL/mL has the effect of reducing
the expression of the antibiotic resistance gene bla-OXA-2. The essence has no inhibitory effect, however, on the Housekeeping DNA
gyrase-A gene.
Conclusions: This study indicates that Satureja khuzestaniea essence has inhibitory effects on the gene expression of antibiotic resistance
in bla-OXA-23 that has a high MIC. Given that this essence has a good inhibitory effect on gene expression in MDR Acinetobacter
baumannii and bla-OXA-23, the results indicate that it could be used as a natural way to prevent the growth of Acinetobacter baumannii.