Abstract:
An alarming increase in bacterial strains resistant to existing antibacterial
agents demands a renewed effort to seek agents effective against
pathogenic bacteria resistant to antibacterials.
The aim of this study was to study the antibacterial activity of different
concentrations of petroleum ether and methanol extracts of medicinal
plant Nigella sativa (seeds) using cup-plate agar diffusion method on
slected clinical isolates of bacteria.
The study was conducted in Khartoum state, Sudan, during the period
from June to November 2015.
One hundred forty four samples were collected form urine, wound and
stool, 103/144 (72%) showed bacterial growth, from which nine types of
pathogenic bacteria were isolated and identified using Gram stain,
biochemical reactions and tested for their susceptibility to a number of
antibiotics. Those were resistant to three or more antibiotics were tested
for their sensitivity to Nigella sativa extracts. The tested isolates included,
Klebsiella pneumoniae 32(31%), Escherichia coli 22(21%),
Staphylococcus aureus 21(20%), Proteus mirabilis 11(11%) and
Pseudomonas aeruginosa 9(9%).
The petroleum ether and methanol extract of Nigella sativa were screened
for their antibacterial activity against standard and clinical isolates.
Petroleum ether extract of Nigella sativa showed pronounced dose
dependant antibacterial activity on standard strains and clinical isolates,
while methanolic extract showed no activity.
Petroleum ether extract of Nigella sativa showed antibacterial activity
against standard and clinical isolates of S.aureus, K.pneumoniae and
E.coli, while only standard strains of P. mirabilis and Ps. aeruginosa
were sensitive to it.
