Inhibition of Biofilm Produced by Methicillin-Resistant Staphylococcus Aureus (MRSA) by Thymoquinone.

Multidrug resistance is a leading public health challenge that is causing a significant increase in mortality and morbidity. If antimicrobial resistance (AMR) remains unsolved, it may cause 10 million deaths every year. Along with a public health concern, it is also a financial concern that would cause 2-3.5% reduction in Gross Domestic Product (GDP) and a 100 trillion USD loss to the world. One of the ways to combat AMR is to discover new antibiotics. This study was aimed to evaluate the antibiofilm and antibacterial potencies of essential oil of Nigella sativa. Standard microbiological guidelines (CLSI) were used for the identification and antibiogram of selected strains of MRSA. Moreover, a time-kill assay of MRSA against Thymoquinone extracted from Nigella Sativa was also performed. Five strains, including four MRSA strains from implants related infections and one standard strain ATCC 25923, were examined. GC-MS identified components of essential oil of Nigella Sativa. Thymoquinone and p-cymene, major compounds of essential oil, were subjected to antibacterial and antibiofilm activities. Thymoquinone revealed strong inhibitory activities against MRSA strains. Zone inhibition measured 22 to 44 mm, and MIC values ranged from 26 to 43 Ul/mL. Thymoquinone also exhibited strong antibiofilm activity against biofilm producer MDR strains of Staphylococcus aureus.