In vitro antimicrobial activity of Nigella sativa seeds extracts against multiple antibiotics resistant bacteria isolated from clinical specimens

ABSTRACT

To study the effect of Nigella sativa seeds against standard and multiple antibiotics resistant bacteria. Different extracts of N. sativa L. [N.O. Family Ranunculaceae] seeds were tested in varying dilutions for antimicrobial activity against standard strains and clinical isolates of various bacteria by Agar disc diffusion technique using impregnated filter paper discs on inoculated Muellar Hinton agar plates. Commercial antibiotic sensitivity testing discs were used for sensitivity testing and comparison. Methanolic extract showed highest antibacterial activity and zone of inhibition was seen even up to 1100 dilution. Among the tested clinical strains, resistant to a number of antibiotics, antibacterial activity was more against gram +ve than gram -ve bacteria. Among gram +ve bacteria tested, Staphylococcus aureus, Staphylococcus epidermidis other coagulase -ve Staphylococci and Streptococcus pyogenes were found sensitive to methanolic extract. Among gram -ve bacteria tested, Escherichia coli and Pseudomonas aeruginosa were found sensitive. Out of 155 strains tested, most of them were resistant to a number of antibiotics and 102 were inhibited by the methanolic extract. Methanolic extract of Nigella sativa is found active against many sensitive as well as multiple antibiotics resistant bacteria isolated from clinical specimens, even up to the dilution of 1100 and 150 respectively