JMI Laboratories, North Liberty, IA 52317, USA.
Diagn Microbiol Infect Dis. 2010 Mar;66(3):329-31. doi: 10.1016/j.diagmicrobio.2009.09.017.
We evaluated the activity of daptomycin (minimum inhibitory [MIC] and bactericidal [MBC] concentration) against Staphylococcus aureus strains with elevated (2 microg/mL) vancomycin MIC values. A total of 410 contemporary clinical S. aureus isolates (282 from the United States and 128 from Europe) with vancomycin MIC values of 2 microg/mL were tested by reference broth microdilution method. Vancomycin MBC and the presence of vancomycin-heteroresistant population (heterogeneous vancomycin-intermediate S. aureus [hVISA]) were evaluated in 31 randomly selected strains. Overall, 97.3% of isolates were susceptible to daptomycin (MIC(90), 0.5 microg/mL). Daptomycin exhibited potent bactericidal activity with MBC values at the MIC concentration (74.2%) or 1 log(2) dilution above the MIC (25.8%). In contrast, vancomycin MBC was > or = 32 microg/mL in 12.9% of strains tolerance, and 25.8% of strains tested positive for hVISA (AB BIODISK GRD Etest, Solna, Sweden). In conclusion, S. aureus strains with vancomycin MIC of 2 microg/mL showed high rates of hVISA and vancomycin tolerance. Daptomycin retained potent bactericidal activity against S. aureus with decreased susceptibility to vancomycin.
我们评估了达托霉素（最低抑菌[MIC]和杀菌[MBC]浓度）对万古霉素 MIC 值升高（2μg/ml）的金黄色葡萄球菌菌株的活性。通过参考肉汤微量稀释法检测了总共 410 株具有 2μg/ml 万古霉素 MIC 值的当代临床金黄色葡萄球菌分离株（美国 282 株，欧洲 128 株）。在 31 株随机选择的菌株中评估了万古霉素 MBC 和万古霉素异质性耐药人群（异质性万古霉素中介金黄色葡萄球菌[hVISA]）的存在。总体而言，97.3%的分离株对达托霉素敏感（MIC90，0.5μg/ml）。达托霉素具有强大的杀菌活性，MBC 值与 MIC 浓度相同（74.2%）或高于 MIC 1 对数稀释度（25.8%）。相比之下，在 12.9%的菌株中，万古霉素 MBC 值>或=32μg/ml 存在耐药性，25.8%的菌株检测到 hVISA 阳性（AB BIODISK GRD Etest，瑞典索尔纳）。总之，万古霉素 MIC 值为 2μg/ml 的金黄色葡萄球菌菌株表现出高 hVISA 和万古霉素耐药率。达托霉素对万古霉素敏感性降低的金黄色葡萄球菌仍具有强大的杀菌活性。
