University of Wales Institute Cardiff, Western Avenue, Cardiff CF5 2YB, UK.
J Antimicrob Chemother. 2011 Nov;66(11):2536-42. doi: 10.1093/jac/dkr340. Epub 2011 Sep 7.
The aim of this study was to investigate the effect of manuka honey, artificial honey and an antibacterial component (methylglyoxal) on cell division in methicillin-resistant Staphylococcus aureus (MRSA).
Viability of epidemic MRSA-15 NCTC 13142 incubated with manuka honey, artificial honey and methylglyoxal was determined, and structural effects monitored by electron microscopy. Activity of murein hydrolase (a peptidoglycan-degrading enzyme implicated in cell separation, encoded by atl) was estimated by cell wall hydrolysis and zymography; expression of atl was quantified by real-time PCR.
Growth of MRSA was inhibited by 5%, 10% and 20% (w/v) manuka honey and 10% (w/v) artificial honey containing methylglyoxal, but not 10% (w/v) artificial honey. Statistically significantly increased numbers of cells containing septa and increased cell diameter (P < 0.001 and P < 0.001, respectively) were found in MRSA exposed to 5%, 10% or 20% (w/v) manuka honey, but not 10% (w/v) artificial honey with and without methylglyoxal. Intracellular activity of murein hydrolase was elevated in MRSA grown in 10% (w/v) artificial honey and at undetectable levels in MRSA treated with 10% (w/v) manuka honey. Increased atl expression was found in MRSA treated with 10% (w/v) manuka honey and 10% artificial honey containing methylglyoxal.
Enlarged cells containing septa were observed in MRSA exposed to inhibitory concentrations of manuka honey, suggesting that cell division was interrupted. These changes were not caused by either the sugars or methylglyoxal in honey and indicate the presence of additional antibacterial components in manuka honey.
本研究旨在探讨麦卢卡蜂蜜、人造蜂蜜和一种抗菌成分（甲基乙二醛）对耐甲氧西林金黄色葡萄球菌（MRSA）细胞分裂的影响。
用麦卢卡蜂蜜、人造蜂蜜和甲基乙二醛孵育流行的 MRSA-15 NCTC 13142，通过电子显微镜监测其结构效应。通过细胞壁水解和同工酶测定法估计肽聚糖水解酶（一种与细胞分离有关的肽聚糖降解酶，由 atl 编码）的活性；通过实时 PCR 定量 atl 的表达。
5%、10%和 20%（w/v）的麦卢卡蜂蜜以及含有甲基乙二醛的 10%（w/v）的人造蜂蜜抑制了 MRSA 的生长，但 10%（w/v）的人造蜂蜜不含甲基乙二醛。在 5%、10%或 20%（w/v）的麦卢卡蜂蜜暴露下，MRSA 中发现了含有隔膜的细胞数量显著增加，细胞直径也显著增加（P < 0.001 和 P < 0.001），但在含有和不含有甲基乙二醛的 10%（w/v）的人造蜂蜜中没有发现这种情况。在 10%（w/v）的人造蜂蜜中生长的 MRSA 中，细胞内肽聚糖水解酶的活性升高，而在用 10%（w/v）的麦卢卡蜂蜜处理的 MRSA 中，该活性无法检测到。在用 10%（w/v）的麦卢卡蜂蜜和含有甲基乙二醛的 10%人造蜂蜜处理的 MRSA 中，atl 的表达增加。
在暴露于麦卢卡蜂蜜抑制浓度的 MRSA 中观察到含有隔膜的放大细胞，表明细胞分裂被中断。这些变化不是由蜂蜜中的糖或甲基乙二醛引起的，这表明麦卢卡蜂蜜中存在其他抗菌成分。
