eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2016-09-25 13 3 1787 1796 10.13005/bbra/2331 16165 article Shapoor Heidari Chaleshtori 1 Mehrdad Ataie Kachoie 1 Department of Herbal Medicine, College of Food and Drug, Shahrekord Branch, Islamic Azad University, Shareakord, Iran. Abstract Application of various types of fertilizers can effect on biological activities of Calendula officinalis. The present investigation was aimed to study the chemical components and antimicrobial effects of C. officinalisgrown under chemical and biological conditions on methicillin-resistant Staphylococcus aureus.Four hundred samples of hospital infections were collected and cultured. MRSA strains were subjected to the disk diffusion and GC-Mass. One-hundred out of 400samples of hospital infections were positive for MRSA (25%). All isolates were also positive for mecA gene. Forty different chemical components were detected in the C. officinalis. The most variable components were found in the control group (1,8-cineole (30.456%), γ-terpinene (25.547%), terpinolene (4.584%), α-terpineol (4.490%) and trans-β-ocinene (4.153%)). Application of biologic and chemical fertilizers caused significant increase in the levels of some chemical components (P<0.05).MRSA strains harbored the highest levels of resistance against tetracycline (95%), ampicillin (92%), penicillin (90%), gentamycin (88%) and ciprofloxacin (77%). Control group had the highest antimicrobial effects but essential oil of the C. officinalis enriched with both fertilizers were effective on resistant MRSA. Use of C. officinalis growthunder bothchemical and biologic fertilizers has been recommendedas a primary approach for synthesis of effective antibiotic. https://www.biotech-asia.org/vol13no3/chemical-composition-and-antimicrobial-effects-of-calendula-officinalis-grown-under-chemical-and-biological-conditions-on-the-methicillin-resistant-staphylococcusaureus-isolated-from-hospital-infectio/ Calendula officinalis; Chemical components; Antimicrobial effects; Methicillin resistant Staphylococcus aureus; Biologic fertilizer; Chemical fertilizer