ABSTRACT

Objectives

This multicenter study aimed to assess the performances of gradient diffusion (GD) method in comparison to broth microdilution (BMD) method for susceptibility testing of dalbavancin, daptomycin, vancomycin, and teicoplanin.

Methods

Minimum Inhibitory Concentrations (MICs) were retrospectively determined concomitantly by BMD and GD methods, for 93 staphylococci and enterococci isolated from clinical samples. BMD was considered as the gold standard. Essential (EA) and categorical agreements (CA) were calculated. Discordant categorical results were categorized as major (ME) and very major errors (VME).

Results

EA and CA were 95.7% and 96.8%, 82.8% and 100%, 97.8% and 96.8%, and 94.6% and 95.7% for dalbavancin, daptomycin, vancomycin, and teicoplanin respectively. Concerning dalbavancin, 3 ME without any VME were observed and discrepancies were low (≤ to 2 two-fold dilutions) between both methods. VME were noted in 1 and 3 cases for vancomycin and teicoplanin, respectively, and resulted from 1 two-fold dilution discrepancy in each case. EA was lower for daptomycin. When they were discrepant, BMD MICs were systematically higher than GD ones. Nevertheless, no categorical discrepancy was noted.

Conclusions

GD appears as an acceptable and convenient alternative for dalbavancin, vancomycin, and teicoplanin MICs determination. Our study also emphasizes how achieving accurate daptomycin MICs remains challenging.

中文翻译：

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梯度扩散法对达巴万星和比较剂药敏试验的准确性

摘要

目标

这项多中心研究旨在评估梯度扩散 (GD) 方法与微量肉汤稀释 (BMD) 方法在达巴万星、达托霉素、万古霉素和替考拉宁的敏感性测试中的性能。

方法

对于从临床样本中分离的 93 种葡萄球菌和肠球菌，通过 BMD 和 GD 方法同时回顾性测定最低抑菌浓度 (MIC)。BMD被认为是金标准。计算了基本（EA）和分类协议（CA）。不一致的分类结果被归类为重大（ME）和非常重大错误（VME）。

结果

达巴万星、达托霉素、万古霉素和替考拉宁的EA和CA分别为95.7%和96.8%、82.8%和100%、97.8%和96.8%、94.6%和95.7%。关于达巴万星，观察到没有任何 VME 的 3 ME，并且两种方法之间的差异很小（≤ 至 2 倍稀释）。万古霉素和替考拉宁分别在 1 例和 3 例中出现 VME，这是由于每例中有 1 倍稀释度差异造成的。达托霉素的 EA 较低。当它们不一致时，BMD MIC 系统地高于 GD 的。然而，没有发现分类差异。

结论

GD 似乎是达巴万星、万古霉素和替考拉宁 MIC 测定的可接受且方便的替代品。我们的研究还强调了如何实现准确的达托霉素 MIC 仍然具有挑战性。