TY - JOUR T1 - 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 TT - بررسی ترکیبات شیمیایی عصاره گیاه گل بی مرگ (Helichrysum artemisiodes)، تاثیر آن بر روی تشکیل بیوفیلم و بیان ژن icaD در جدایه‌های بالینی مقاوم به متی سیلین استافیلوکوکوس اورئوس JF - sjimu JO - sjimu VL - 25 IS - 1 UR - http://sjimu.medilam.ac.ir/article-1-3863-en.html Y1 - 2017 SP - 180 EP - 194 KW - Helichrysum artemisiodes KW - Staphylococcus areus KW - Biofilm KW - icaD N2 - 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. M3 10.29252/sjimu.25.1.180 ER -