The Effect of Manuka Honey on the Cell Cycle of MRSA
Preliminary studies have shown that manuka honey affects the cell cycle of MRSA by
impeding cell division, but mode of action was unknown. Cell division depends on the
formation of septa and cleavage of peptidoglycan at cytokinesis. This study investigated
how manuka honey might alter the cell cycle of EMRSA-15.
Physiological and chemical changes in the bacteria exposed to manuka honey were
determined using time to kill studies, confocal and electron microscopy. Data indicated that
honey had a bactericidal effect on MRSA, inhibiting the cell cycle cytokinesis. Increased
septum formation was noted in honey treated cells by transmission electron microscopy.
Cell division components including FtsZ and Endo-B-N-Acetylglucosaminidase were
investigated using cell wall turbidity assays, zymography, immunofluorescence and
immuno gold labelling. Manuka honey treated MRSA cells showed a marked reduction in
hydrolase activity after 12 hours compared to untreated cells. The immunofluorescence
indicated an initial increase in FtsZ production followed by a significant decrease by 24
hours. PCR of FtsZ showed a 10% increase in production after 1 and 4 hours. Localization
by gold labelling gave inconclusive results.
Immunofluorescence of Endo-B-N-Acetylglucosaminidase showed a decrease in the
amount of enzyme over 24 hours and localization by gold labelling indicated altered
distribution of this enzyme. PCR showed no significant difference in expression.
2-D electrophoresis showed a differing proteomic profile between control cells and those
treated with honey, with a potential target protein being identified.
Methylglyoxal (an antibacterial component of manuka honey) was investigated after a
report named this as potentially the active component of manuka honey. Results showed it
has an effect but is not wholly responsible for the effects induced by manuka honey.
It was concluded that increased numbers of cells with septa were formed and alteration in
production of proteins and enzymes resulted in MRSA cells exposed to bactericidal
concentrations of manuka honey. The work was also carried out with artificial honey
controls, indicating that effects seen were not due to sugar content within honey or
- School of Sport and Health Sciences