Antibacterial activity of house fly-maggot extracts against MRSA (Methicillin-resistant Staphylococcus aureus) and VRE (Vancomycin-resistant enterococci).

ABSTRACT

The principal objective of this study was to determine the in vitro antibacterial activity of the water-soluble protein enzymatic hydrolysates and the ethanol (EtOH)-extracted fraction obtained from fly-maggots (Musca domestica L.) against MRSA (methicillinresistant Staphylococcus aureus) strains and VRE (Vancomycin-resistant enterococci) 5117 strain. The water soluble protein enzymatic hydrolysates were prepared via 4 or 8 hr of incubation after mixing with the water-soluble protein extracted from the fly-maggots plus thermolysin. The EtOH-extracts A was prepared by homogenizing after mixing with the fly-maggots plus pure EtOH at room temperature. The EtOH-extracts B and C was obtained via filtering after stationing for 24 hr at 4-20oC using the EtOH-extracts A, respectively. The growth inhibition curves for MRSA strain 3595 and VRE strain 5117 in the water-soluble protein enzymatic hydrolysates were increased and evidenced concentration-dependent inhibition in the 8-hr hydrolysate as compared with the 4-hr hydrolysate (p<0.05). The growth inhibition curves for MRSA and VRE strains in the EtOH-extracted fraction obtained from the fly-maggots were high in EtOH-extract C as compared with EtOH-extracts A and B (p<0.05). The minimum inhibitory concentrations (MIC) in the EtOH-extracts C, in which the growth inhibition of MRSA and VRE strains was increased, were determined to be 40, 50, 50, 60, 40 and 60 μg ml-1 in MRSA strains 3598, 3595, 3601, 3589, 3597 and 3595, respectively. While the butanol fraction obtained from EtOH extract C evidenced profound antibacterial activity against the MRSA and VRE strains, the antibacterial activity of the hexane, ethyl acetate, and water layers could not be adequately confirmed.