Synergistic Evaluation of Moringa oleifera, Hunteria umbellate and Azadirachta indica with Antibiotics Against Environmental MRSA Isolates: An In-vitro Study

Abstract

Methicillin-Resistant Staphylococcus aureus (MRSA) is known to show resistance to beta-lactam class of antibiotics. MRSA is among the highest superbugs posing dangerous threats to humans. This study aimed at determining the in-vitro synergistic evaluation of Moringa oleifera, Hunteria umbellate and Azadirachta indica extracts with existing antibiotics (Azithromycin, Clindamycin and Vancomycin) on isolated MRSA from fomites. MRSA was isolated using the BBL™ Oxacillin agar screen test (Müller Hinton Agar with 6 μg/mL Oxacillin and 4% NaCl). The Minimum Bactericidal concentration (MBC) of the MRSA were determined by Agar well diffusion using antibiotics in solitary, plant extracts in solitary, combination of these antibiotics with plant extracts at different concentrations. The agar diffusion assay showed that H. umbellate extract-Azithromycin combination had the least zones of inhibition ≥21.00±1.92 mm in 75% of all isolates testedwhile M. oleifera extract-Azithromycin combination had the highest zones of inhibition ≥22.20 ±2.27 mm. Comparison of bactericidal activities of all plant extracts and antibiotics synergy shows Azithromycin to have a significant value of P>0.05. The agar well diffusion method showed synergistic effects between combination of antibiotics and all extracts with significant increase in the zones of inhibition of the test antibiotics against environmental strains of MRSA. The synergistic interactions indicated that the inhibitory potentials of the plant extracts increased hence, combining natural products derived from phytochemicals and antibiotics could be another way to mitigate and fight against resistant infectious bacteria.