Revised Reference Broth Microdilution Method for Testing Telavancin: Effect on MIC Results and Correlation with Other Testing Methodologies
Revised Reference Broth Microdilution Method for Testing Telavancin: Effect on MIC Results and Correlation with Other Testing Methodologies
复制标题
DOI：
10.1128/aac.03172-14
复制
发表时间：
2014-09-01
影响因子：
4.9
通讯作者：
Jones, Ronald N.
中科院分区：
文献类型：
--
作者：
Farrell, David J.;Mendes, Rodrigo E.;Jones, Ronald N.
根据CLSI关于水不溶性试剂的建议，修订了特拉万星的参考肉汤微量稀释（BMD）抗菌药物敏感性试验方法，以包括二甲亚砜（DMSO）作为冷冻形式样本组制备的溶剂和稀释剂。还将聚山梨酯80（P-80）添加到试验培养基中，以最大限度地减少与塑料表面结合相关的已证实药物损失。选择462株革兰氏阳性分离株，包括对对照药物敏感性降低的挑战微生物集，并使用特拉万星的修订方法进行检测，并将MIC结果与先前建立的方法和几种Sensititre干型BMD检测板制剂检测的结果进行比较。当对葡萄球菌和肠球菌进行检测时，修订后的方法提供的MIC结果比以前的方法低2- 8倍，导致葡萄球菌的MIC 50值为0.03 - 0.06 μ g/ml，屎肠球菌和粪肠球菌的MIC 50值分别为0.03和0.12 μ g/ml。当在补充血液的肉汤中检测链球菌时，观察到不太显著的MIC降低（1至2 log（2）稀释步骤），这表明两种方法的MIC 50值相似。然而，当使用修订后的方法和之前的方法进行检测时，肺炎链球菌的MIC 50结果分别为0.008和0.03 μ g/ml。与修订的测试相比，注意到一种候选干型面板配方的基本一致率最高（>= 94.0%）。修订后的BMD方法提供了特拉万星的较低MIC结果，特别是在针对葡萄球菌和肠球菌进行测试时。这是次要的，因为使用DMSO进行组生产和P-80的存在，这确保了适当的特拉万星测试浓度并导致更准确的MIC测定。此外，应用先前方法的早期研究低估了体外药物效力。
The reference broth microdilution (BMD) antimicrobial susceptibility testing method for telavancin was revised to include dimethyl sulfoxide (DMSO) as a solvent and diluent for frozen-form panel preparation, following the CLSI recommendations for water-insoluble agents. Polysorbate 80 (P-80) was also added to the test medium to minimize proven drug losses associated with binding to plastic surfaces. Four hundred sixty-two Gram-positive isolates, including a challenge set of organisms with reduced susceptibilities to comparator agents, were selected and tested using the revised method for telavancin, and the MIC results were compared with those tested by the previously established method and several Sensititre dry-form BMD panel formulations. The revised method provided MIC results 2- to 8-fold lower than the previous method when tested against staphylococci and enterococci, resulting in MIC50 values of 0.03 to 0.06 mu g/ml for staphylococci and 0.03 and 0.12 mu g/ml for Enterococcus faecium and Enterococcus faecalis, respectively. Less-significant MIC decreases (1 to 2 log(2) dilution steps) were observed when testing streptococci in broth supplemented with blood, which showed similar MIC50 values for both methods. However, Streptococcus pneumoniae had MIC50 results of 0.008 and 0.03 mu g/ml when tested by the revised and previous methods, respectively. Highest essential agreement rates (>= 94.0%) were noted for one candidate dry-form panel formulation compared to the revised test. The revised BMD method provides lower MIC results for telavancin, especially when tested against staphylococci and enterococci. This is secondary to the use of DMSO for panel production and the presence of P-80, which ensure the proper telavancin testing concentration and result in a more accurate MIC determination. Moreover, earlier studies where the previous method was applied underestimated the in vitro drug potency.