AU - Mirzaie, Amir AU - Noorbazargan, Hassan AU - Khatami, Seyed Hamid Reza Khatami AU - Sadat Shandiz, Seyed Ataollah AU - Rahimi, Arian AU - Bagheri keshtali, Ali asghar TI - Evaluation of Chemical Composition of Helichrysum artemisioides Extract Its Effect on Biofilm Formation and IcaD Gene Expression in Clinical Isolates of Methicillin-Resistant Staphylococcus aureus PT - JOURNAL ARTICLE TA - sjimu JN - sjimu VO - 25 VI - 1 IP - 1 4099 - http://sjimu.medilam.ac.ir/article-1-3863-en.html 4100 - http://sjimu.medilam.ac.ir/article-1-3863-en.pdf SO - sjimu 1 ABĀ  - Introduction: Staphylococcus aureus is a major causative agent of nosocomial infections which produces a wide range of diseases due to biofilm formation. This study aimed to investigate the phytochemical composition of Helichrysum artemisioides extract, its anti-biofilm effects on clinical isolates of ­methicillin-resistant Staphylococcus aureus, as well as, analysis of icaD gene expression. Materials & methods: First, the phytochemical composition of H. artemisioides extract was studied by GC/MS method. Then, the biofilm formation capacity of 50 clinical isolates of S. aureus was evaluated by Congo red agar and polymerase chain reaction (PCR). Finally, after treatment of strains with SubMIC ­concentration of the extract within 24 hours, the expression level of icaD gene was evaluated by Real Time PCR. Findings: The phytochemical analysis of extract showed 52 compounds, including α-Pinene (12.5%) and Carvacrol (8.6%) as the major components. The evaluation of biofilm formation test shows that out of 50 strains of S. aureus, 10 strains (20%) were positive for biofilms formation. Also, after treatment of selected strains by SubMIC concentration of the extract, the gene expression quantitation of icaD was down-regulated significantly (P<0.05). Discusion & conclusions: Due to the significant effects of H. artemisioides extract on biofilm formation, it seems that the extract could be used as complementary therapy to inhibit S. aureus biofilm. CP - IRAN IN - Department of Biology, Roudehen Branch, Islamic Azad University, Roudehen, Iran LG - eng PB - sjimu PG - 180 PT - Research YR - 2017