Anti-Bacterial Potential of Azadirachta Indica Extract Against Staphylococcus Aureus

Background: Various parts of the Azadirachta indica (Neem) tree have shown effects against microbes of wide variety. Cheaper & newer antimicrobial agents with greater efficacy and safety may be developed by screening this medicinal plant for bioactive compounds. Aim: To evaluate the in vitro antibacterial activity of Neem leaves extract (Azadirachta indica extract) against clinical isolates of Staphylococcus aureus & methicillin resistant Staphylococcus aureus by Agar Dilution Method. Method: The in vitro activity of Neem leaves extract against Staphylococcus aureus (n=33); including 17 methicillin resistant Staphylococcus aureus clinical isolates was determined. Standard agar dilution method was used for the determination of Minimum inhibitory concentration of Neem leaves extract with different dilutions of Neem. Standard control strains ATCC 22922 Staphylococcus aureus and ATCC 33591 Staphylococcus aureus were used. Results: Strong antimicrobial activity was exhibited by Azadirachta indica leaf extract antagonist to all bacterial species under study at all the concentrations tested. The range of different dilutions of Neem used against Staphylococcus aureus and MRSA showed that for Staphylococcus aureus the dilution range is 4-8mg/ml and for MRSA this value ranges between 2-4 mg/ml. MIC50 of Neem leaves extract was comparable for staphylococci and methicillin resistant S. Aureus (8mg/L); however at MIC(90)Neem leaves extract was twofold more active against methicillin resistant S.aureus(4mg/L) than staphylococci (8mg/L) Conclusion: Azadirachta. indica (Neem) leaf extract exhibited stronger antibacterial activity against methicillin resistant Staphylococcus aureus strains (MRSA) than Staphylococcus aureus.