The Effect of Manuka Honey on the Cell Cycle of MRSA

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