Taha Mariam, Kalab Miloslav, Yi Qi-Long, Landry Carey, Greco-Stewart Valerie, Brassinga Ann Karen, Sifri Costi D, Ramirez-Arcos Sandra
Canadian Blood Services, Ottawa, Ontario, Canada.
Transfusion. 2014 Nov;54(11):2974-82. doi: 10.1111/trf.12728. Epub 2014 May 29.
A one-step skin disinfection method containing 2% chlorhexidine-gluconate (CHG) and 70% isopropyl alcohol (IPA) is currently used by blood suppliers worldwide. Reports of bacterially contaminated platelet concentrates (PCs) indicate that skin disinfection is not fully effective. Approximately 20% of skin microflora exist as surface-attached aggregates (biofilms), known for displaying increased resistance to disinfectants. This study was aimed at determining whether skin microflora biofilm-positive Staphylococcus epidermidis and Staphylococcus capitis are resistant to CHG and/or IPA.
Free-floating cells and mono or dual (1 : 1 ratio) biofilms of S. epidermidis and S. capitis were exposed to CHG, IPA, or CHG/IPA for 30 seconds, simulating skin disinfection practices. Residual viable cells were quantified by colony counting. Morphology of disinfectant-treated S. epidermidis biofilms was examined by scanning electron microscopy. Treated S. epidermidis and S. capitis biofilms were inoculated into PCs and bacterial concentrations were determined on Days 0 and 5 of storage.
Treatment of staphylococcal biofilm cells with all disinfectants caused cell damage and significant reduction in viability, with CHG/IPA being the most effective. However, biofilms were significantly more resistant to treatment than free-floating cells. Disinfectant-treated S. epidermidis proliferated better in PCs than S. capitis, especially when grown as monospecies biofilms.
Although CHG/IPA is effective in reducing the viability of S. epidermidis and S. capitis biofilms, these organisms are not completely eliminated. Furthermore, disinfectant-treated staphylococcal biofilms multiply well in PCs. These results demonstrate that the biofilm-forming capability of the skin microflora reduces the bactericidal efficiency of blood donor skin disinfectants.
目前全球血液供应机构都在使用一种含有2%葡萄糖酸氯己定（CHG）和70%异丙醇（IPA）的一步式皮肤消毒方法。有关血小板浓缩液（PC）被细菌污染的报告表明，皮肤消毒并不完全有效。大约20%的皮肤微生物以表面附着聚集体（生物膜）的形式存在，这种聚集体对消毒剂具有更强的抵抗力。本研究旨在确定皮肤微生物生物膜阳性的表皮葡萄球菌和头状葡萄球菌是否对CHG和/或IPA具有抗性。
将表皮葡萄球菌和头状葡萄球菌的浮游细胞以及单种或两种（1:1比例）生物膜暴露于CHG、IPA或CHG/IPA中30秒，模拟皮肤消毒操作。通过菌落计数对残留活细胞进行定量。通过扫描电子显微镜检查经消毒剂处理的表皮葡萄球菌生物膜的形态。将经处理的表皮葡萄球菌和头状葡萄球菌生物膜接种到PC中，并在储存的第0天和第5天测定细菌浓度。
用所有消毒剂处理葡萄球菌生物膜细胞均导致细胞损伤并使活力显著降低，其中CHG/IPA最为有效。然而，生物膜比浮游细胞对处理的抗性明显更强。经消毒剂处理的表皮葡萄球菌在PC中比头状葡萄球菌增殖得更好，尤其是当以单种生物膜形式生长时。
尽管CHG/IPA能有效降低表皮葡萄球菌和头状葡萄球菌生物膜的活力，但这些微生物并未被完全清除。此外，经消毒剂处理的葡萄球菌生物膜在PC中能很好地繁殖。这些结果表明，皮肤微生物的生物膜形成能力降低了献血者皮肤消毒剂的杀菌效率。
