Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
Division of Medical Microbiology and Virology, Providence Health Care, St. Paul's Hospital, Vancouver, British Columbia, Canada.
J Med Microbiol. 2024 Sep;73(9). doi: 10.1099/jmm.0.001881.
Colistin resistance testing methods such as broth microdilution (BMD) are time-consuming and labour intensive for clinical laboratories. MBT Lipid Xtract Kit on MALDI Biotyper Sirius System (Bruker, Billerica, MA, USA) utilizes lipidomic analysis to identify specific cell wall modifications associated with colistin resistance. We compared MBT to BMD (ComASP Colistin, Liofilchem) across 36 Gram-negative isolates (non-resistant MIC ≤2 µg ml, resistant MIC ≥4 µg ml). All samples were tested twice on MBT with discrepant results repeated before assessing categorical agreement between MBT and BMD. 44.4% (16/36) of isolates were colistin resistant via BMD. MBT Lipid Xtract had 80.6% agreement (29/36) with BMD, with 5/7 discrepancies corrected to match upon repeat testing. There was 100% agreement for isolates (=16). The whole-genome sequencing was completed on the two discrepant isolates, with variants within colistin resistance-associated loci identified (MIC 0.5 µg ml: S30T, T246A, N212T, S253G, Q287K and MIC >16 µg ml: S30T, R90insRN, T246A, E57G, S253G). Further evaluation, particularly for non-, of MBT is required prior to implementation in clinical laboratories.
黏菌素耐药检测方法，如肉汤微量稀释法（BMD），对临床实验室来说既耗时又费力。MALDI Biotyper Sirius 系统上的 MBT Lipid Xtract 试剂盒（Bruker，Billerica，MA，美国）利用脂质组学分析来识别与黏菌素耐药相关的特定细胞壁修饰。我们比较了 MBT 与 BMD（ComASP 黏菌素，Liofilchem）在 36 株革兰氏阴性菌分离株中的应用（非耐药 MIC≤2μg/ml，耐药 MIC≥4μg/ml）。所有样本均在 MBT 上重复测试两次，对结果不一致的样本进行重复测试，以评估 MBT 与 BMD 的分类一致性。36 株分离株中有 44.4%（16/36）通过 BMD 法检测为黏菌素耐药。MBT Lipid Xtract 与 BMD 法的一致性为 80.6%（29/36），其中 5/7 个差异在重复测试时得到纠正。16 株一致的分离株的一致性为 100%。对两个不一致的分离株进行了全基因组测序，鉴定出与黏菌素耐药相关的基因座内的变异（MIC 0.5μg/ml：S30T、T246A、N212T、S253G、Q287K；MIC＞16μg/ml：S30T、R90insRN、T246A、E57G、S253G）。在将 MBT 应用于临床实验室之前，需要对其进行进一步评估，特别是对非耐药菌的评估。
