Valero-Guillén Pedro L, Fernández-Natal Isabel, Marrodán-Ciordia Teresa, Tauch Andreas, Soriano Francisco
Departamento de Genética y Microbiología, Facultad de Medicina, Universidad de Murcia, Spain; Instituto Murciano de Investigación Biosanitaria (IMIB), Spain.
Departamento de Microbiología Clínica, Complejo Asistencial Universitario de León-Sacyl, León, Spain; Instituto de Biomedicina (IBIOMED), Universidad de León, León, Spain.
Chem Phys Lipids. 2016 Mar;196:24-32. doi: 10.1016/j.chemphyslip.2016.02.002. Epub 2016 Feb 8.
Dermabacter hominis is a medically important actinobacterial inhabitant of human skin, although it is rarely implicated in infections. The lipid composition of D. hominis is revisited in this study in the context of its natural resistance to daptomycin, an antibiotic whose activity is influenced by membrane lipids. Thin layer chromatography and mass spectrometry revealed that this species contains phospholipids and glycolipids. Using electrospray ionization time of flight mass spectrometry (exact mass) and gas chromatography-mass spectrometry, the major phospholipid of D. hominis was identified as plasmanyl-phosphatidylglycerol (pPG), because it presented one alkyl chain and one acyl chain in the glycerol moiety of the molecule. The structure of the major glycolipid (GL1) was studied by combined gas-liquid chromatography, mass spectrometry and nuclear magnetic resonance, and was established as galactosyl-α-(1→2)-glucosyl-alkyl-acyl-glycerol. Lipid analyses showed differences between one daptomycin-resistant (DAP-R) strain and one daptomycin-sensitive (DAP-S) strain growing in the presence of the antibiotic: DAP-R tended to accumulate GL1 and to reduce pPG, whereas DAP-S maintained high proportions of pPG. The results demonstrate the existence of ether-linked lipids in D. hominis and reveal a differential distribution of phospholipids and glycolipids according to the sensitivity or resistance to daptomycin, although the mechanism(s) operating in the resistance to the antibiotic remain(s) to be elucidated.
人皮肤微杆菌是人类皮肤中一种具有医学重要性的放线菌居民，尽管它很少与感染有关。在本研究中，鉴于人皮肤微杆菌对达托霉素具有天然抗性（达托霉素的活性受膜脂影响），对其脂质组成进行了重新研究。薄层色谱法和质谱分析表明，该菌种含有磷脂和糖脂。使用电喷雾电离飞行时间质谱法（精确质量）和气相色谱 - 质谱联用，人皮肤微杆菌的主要磷脂被鉴定为甘油磷脂酰甘油（pPG），因为它在分子的甘油部分呈现一条烷基链和一条酰基链。通过气液色谱、质谱和核磁共振联用对主要糖脂（GL1）的结构进行了研究，并确定其为半乳糖基-α-(1→2)-葡糖基-烷基-酰基甘油。脂质分析显示，在抗生素存在下生长的一株达托霉素抗性（DAP-R）菌株和一株达托霉素敏感（DAP-S）菌株之间存在差异：DAP-R菌株倾向于积累GL1并减少pPG，而DAP-S菌株则保持较高比例的pPG。结果表明人皮肤微杆菌中存在醚键连接的脂质，并揭示了根据对达托霉素的敏感性或抗性，磷脂和糖脂的分布存在差异，尽管抗生素抗性的作用机制仍有待阐明。
