This study investigates the antimicrobial activity of essential oil obtained from Nigella sativa seeds (Black seed oil). The objectives are to determine the antimicrobial efficacy of black seed oil against selected pathogens such as Pseudomonas aeruginosa (ATCC 27853), Methicillin Resistant Staphylococcus aureus (MRSA), Methicillin sensitive Staphylococcus aureus (MSSA), Staphylococcus pyogenes (ATCC 19615), Escherichia coli (ATCC 25922 and ATCC 35218) and clinically isolated Candida albicans and to compare the ability of microbial growth inhibition with conventional antibiotics that are used for the test organisms. Bacteria were inoculated on Mueller Hinton Agar and Sabouraud Dextrose Agar was used to inoculate C. albicans. Agar well diffusion technique was used to evaluate antimicrobial activity of the test organisms. As Dimethyl sulfoxide (DMSO) was served as the solvent for black seed oil, it was used as the negative control. Among the test organisms, staphylococci; MRSA, MSSA, S. pyogenes and C. albicans were sensitive to the oil. Both two strains of E.coli, P. aeruginosa were resistant to the oil while all test organisms were susceptible to the antibiotics used. The comparative study revealed that all three staphylococci are more susceptible to black seed oil than amoxicillin in tested concentration.

Keywords : Nigella Sativa; Black Seed Oil; Antimicrobial Activity; Antibitic Resistance.