The identification of critical lethal action in antimicrobial mechanism of glycerol monomyristate against foodborne pathogens

Glycerol monomyristate (GMM) is a promising antimicrobial substance due to its broad antibacterial spectrum: however, the critical lethal action in its antimicrobial mechanism for foodborne pathogens remains unclear. In the present study, the inhibitory activities of GMM on Escherichia coli ( E. coli ), Staphylococcus aureus ( S. aureus ) and Candida albicans ( C. albicans ) were compared, and its membrane and intracellular action mechanism was investigated. The results showed that the susceptibility of E. coli to GMM was the highest, followed by S. aureus , and C. albicans being the poorest. Using flow cytometry, the GMM dose causing above 50% permeability ratio on E. coli was lower than that on S. aureus . The images from scanning electron microscope revealed no doses difference existed between the two strains when the obvious cell damage occurred. Furthermore, cell cycle and multiple fluorescent staining assays showed only the cell division of E. coli and S. aureus , excluding that of C. albicans , was obviously affected at 1/4 MIC and 1/2 MIC, indicating that the DNA interfere and subsequent cell division inhibition was likely to be the critical lethal action with doses near MIC, which can also explain the poor sensitivity of C. albicans .