DF Basri, N Jaffar, NM Zin and L Santhana Raj (2013). Electron microscope study of gall extract from Quercus infectoria in combination with vancomycin against MRSA using post antibiotic effect determination. International Journal of Pharmacology 9(2): 150-156
The galls from Quercus infectoria have been considered as an alternative phytofherapeutic treatment against Mefhicillin-Resistant Staphylococcus aureus (MRSA) infection. The aim of the study was to examine the mode of action of the combined effect of an extract of Quercus infectoria with vancomycin against MRSA. The acetone extract from the Q. infectoria was prepared from dried gall powder and the Post-Antibiotic Effect (PAE) time of acetone extract was determined in combination with vancomycin and singly, against American Type Culture Collection (ATCC) 43300 strain using the checkerboard assay. The morphology and ultrastructural changes of MRSA using scanning and transmission electron microscope following 6 h treatments, was also observed. The mean difference of PAE time between the combination and vancomycin was insignificant (p>0.05). This indicated that the acetone extract from Q. infectoria did not significantly prolong the PAE time of vancomycin. Morphology changes in the combination-treated cells showed no evidence of bacterial lysis although cytoplasmic damage was visible from ultrastructural studies. The antagonistic activity of the combined antibacterials shown by electron microscopic study did not correlate with PAE synergism. The acetone extract from Q. infectoria antagonized the bacteriolytic action of vancomycin by acting at the same site of action at different point in the peptidoglycan cycle. This finding indicated that tannin-based medicinal plant targets enzymes involved in the synthesis of MRSA cell wall.