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Organic Chemistry, Microbiology
Aims: This study investigates the antimicrobial activity and mode of action of novel carbohydrate fatty acid (CFA) derivatives against Staphylococcus aureus and methicillin-resistant Staph. aureus (MRSA).
Methods and Results: Minimum inhibitory concentrations (MIC) and the effect of CFA derivatives on lag phase were determined using a broth microdilution method. Lauric acid carbohydrate esters and corresponding ether analogs showed the greatest antimicrobial activity with MIC values between 0.04 to 0.16mmol l-1. Leakage studies at 260nm following exposure to CFA derivatives at 4X MIC showed a significant increase in membrane permeability for all compounds, after ca. 15 minutes exposure except for the lauric beta ether CFA derivative. Further assessment using both BacLight and luminescence ATP assays, confirmed that an increase in membrane permeability and reduced metabolic activity was associated with CFA treatment.
Conclusions: All strains were significantly inhibited by the novel compounds studied and efficacy was related to specific structural features. Cell-membrane permeabilization was associated with CFA treatment and may account for at least a component of the mode of action of these compounds.
Significance and Impact of Study: This study reports the antimicrobial action of CFA compounds against a range of Staph. aureus and MRSA strains, and provides insights into their mode of action.
Bourke, P., Nobmann, P., Dunne, J. and Henehan, G. (2010). In vitro antimicrobial activity and mechanism of action of novel carbohydrate fatty acid derivatives against Staphylococcus aureus and MRSA. Journal of Applied Microbiology, 108, pp.2152-2161. doi:10.1111/j.1365-2672.2009.04622.x