synergistic antimicrobial activity between pentacyclic triterpenoids and antibiotics against staphylococcus aureus strains之间的协同抗菌活性五环的常用药用和抗生素对金黄色葡萄球菌菌株.pdf

Chung et al. Annals of Clinical Microbiology and Antimicrobials 2011, 10:25 /content/10/1/25 RESEARCH Open Access Synergistic antimicrobial activity between pentacyclic triterpenoids and antibiotics against Staphylococcus aureus strains 1 1* 2 Pooi Yin Chung , Parasakthi Navaratnam and Lip Yong Chung Abstract Background: There has been considerable effort to discover plant-derived antibacterials against methicillin- resistant strains of Staphylococcus aureus (MRSA) which have developed resistance to most existing antibiotics, including the last line of defence, vancomycin. Pentacyclic triterpenoid, a biologically diverse plant-derived natural product, has been reported to show anti-staphylococcal activities. The objective of this study is to evaluate the interaction between three pentacyclic triterpenoid and standard antibiotics (methicillin and vancomycin) against reference strains of Staphylococcus aureus. Methods and Results: The activity of the standard antibiotics and compounds on reference methicillin-sensitive and resistant strains of S. aureus were determined using the macrodilution broth method. The minimum inhibitory concentration (MIC) of the compounds was compared with that of the standard antibiotics. The interaction between any two antimicrobial agents was estimated by calculating the fractional inhibitory concentration (FIC index) of the combination. The various combinations of antibiotics and compounds reduced the MIC to a range of 0.05 to 50%. Conclusion: Pentacyclic triterpenoids have shown anti-staphylococcal activities and although individually weaker than common antibiotics produced from bacteria and fungi, synergistically these compounds may use different mechanism of action or pathways to exert