Antibacterial effect of Neem oil on Methicillin resistant Staphylococcus aureus
Dr. Sakshee Gupta, Dr. Gopalkrishna Bhat
Methicillin resistant Staphylococcus aureus (MRSA) is an important hospital acquired pathogen, usually resistant to many antibiotics. This study was aimed at determination of antibacterial effect of Neem oil (Azadirachta indica, N.O. Meliaceae) on MRSA. Antibacterial effect of Neem oil (Medinova chemicals, Bangalore) was studied using 107 strains of MRSA isolated from different clinical specimens. Time kill assay (undiluted Neem oil & 106 bacteria/ml) was performed and the surviving bacteria were detected by culture on blood agar. Minimum Inhibitory Concentration was determined by agar dilution method (10% to 50% concentration of Neem oil in 20 ml of molten nutrient agar by inoculation of 104 CFU /spot on MHA. Out of 107 strains of MRSA, 56 (52.33%) were killed after 1hr exposure to Neem oil, 22(20.56%) were killed after 2 hr exposure, 19(17.75%) were killed after 4 hr & remaining 10(9.34%) were killed after 12 hr exposure to Neem oil. All MRSA strains were killed by Neem oil. On agar dilution, 90 (84.11%) of strains were inhibited at 10% concentration of Neem oil, 14 (13.08%) at 20% and remaining 3(2.80%) were inhibited at 30% concentration of Neem oil. The results are suggestive of antibacterial effect of Neem oil on multidrug resistant MRSA. Since Neem oil exhibited bactericidal effect on MSA, it may find clinical application as a topical antibiotic for MRSA infections.