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Background&Objective: Staphylococcus aurues is on important cause of community and hospital- aquired infections. Caused by methicillin or oxacillin- resistant s.aureus (MRSA) are mainly nosocomial and are increasingly from many countries word wide. Many attempt have been made by the reasearchers to find new compounds as a subsitute for this antibiotics. The aim of this study was to investigate the antimicrobial activity of alcoholic extracts of 20 medical plants species of Golestan provience on clinical and standard strains of MRSA and MSSA and comprative and detect the best medical plant. Materials&Methods: In this study the compunds of the plant were extracted by percolation method and the effect of ethanolic extract of 20 Iranian medical plants against methicillin resistant and methicillin sensitve strains were assessed by disc diffusion method and each test were repeated 3 times and mean inhibition zone were recorded and then, the minimum inhibitory concentration (MIC) of the extracts, that show good inhibition zone in disc diffusion method, was determined by the micro broth dilution method. Results: The results of antibacterial activity of the ethanolic extracts of 20 plants revealed that, the ethamlic extracts of 8 plants have the best effect on strains and the maximum mean inhibition zone was 22.4 mm and the lowest MIC of plants was 0.01 mg/ml. Conclusion: The result of this study indicate that, ethanolic extract of Eucalyptus. Global, Peganum.hermla, Punica.granatum, Berberis.vulgaris, Ttamarixaphylla, Nnigella.sativa, Hypericum.perforatum AND, Artemisia. Herbaalba have the best antibacterial effect against MRSA andMSSA. The result obtained from these plants might be considered sufficent for further study.

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Background and Objective: Staphylococcus aureus (S. aureus) is the most common cause of nosocomial infections. Treatment of Staphylococcal infections has become more complicated due to the emergence of methicillin-resistant S.aureus (MRSA) strains. This study was done to determine the frequency of methicillin resistance encoding gene (mecA) and β-lactamase resistance encoding gene (blaZ) in S. aureus isolates from clinical samples using Polymerase Chain Reaction (PCR) method.
Methods: This descriptive-analytic study was carried out on 59 S. aureus isolates from clinical samples in Gorgan hospitals from January-February 2017 to June-July 2017. All the isolates were identified using gram staining, catalase test, tube coagulase test, growth on Mannitol salt agar medium and the DNase test in the Microbiology Laboratory .Antibiotic resistance was evaluated using the standard disk diffusion.  Iodometric method was used to detect β-lactamase production / activity in this bacterium. PCR test was done to detect mecA and blaZ genes.
Results: All S. aureus isolates (100%) clinical samples possessed blaZ gene, followed by 27 isolates (45.8%) possessed mecA gene (MRSA), which these isolates possessed mecA gene were concurrently positive for blaZ gene. 5% of oxacillin-resistant strains and 3% of cefoxitin-resistant strains possessed mecA gene and 47 isolates (79.4%) carrying blaZ gene were β-lactamase-positive in phenotypic method.
Conclusion: This study showed that in all clinical samples isolated S. aureus isolates which these isolates possessed mecA gene were concurrently positive for blaZ gene.