Multicenter evaluation of ethambutol susceptibility testing of Mycobacterium tuberculosis by agar proportion and radiometric methods
Multicenter evaluation of ethambutol susceptibility testing of Mycobacterium tuberculosis by agar proportion and radiometric methods
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DOI：
10.1128/jcm.40.11.3976-3979.2002
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发表时间：
2002-11-01
影响因子：
9.4
通讯作者：
Ridderhof, J
中科院分区：
文献类型：
--
作者：
Madison, B;Robinson-Dunn, B;Ridderhof, J
结核分枝杆菌乙胺丁醇（EMB）药敏试验结果的重现性一直很困难，原因有很多，包括EMB耐药临界点和敏感菌株MIC之间的范围很窄，BACTEC 460 TB法获得的结果处于临界值，琼脂比例（AP）法测定的小菌落的存在，以及这两种测试方法之间缺乏一致性。为了评估这些问题的频率，在。结核病药物敏感性数据是在一项涉及四个实验室的多中心研究中收集的。实验室之间共享耐药、临界和敏感分离株，以衡量实验室间检测一致性。经BACTEC 460 TB测定为耐药的菌株中有一半经AP法测定为敏感。用BACTEC 460 TB和AP两种方法测定的EMB耐药菌株几乎都对异烟肼耐药。用BACTEC 460 TB方法检测的分离株的结果，除了标准的2.5 μ g/ml外，EMB浓度为3.75 μ g/ml，AP方法没有显示出更好的一致性。虽然这些结果并不表明AP方法比BACTEC 4601，13方法更准确，但实验室不应仅根据BACTEC 460 TB结果报告EMB单一耐药性。只有在通过All方法确认后，才应报告对EMB的单一耐药性。通过BACTEC 460 TB方法或通过使用All方法重复检测无法确认小菌落为耐药，并且似乎不指示耐药。
Reproducibility of ethambutol (EMB) susceptibility test results for Mycobacterium tuberculosis has always been difficult for a variety of reasons, including the narrow range between the critical breakpoint for EMB resistance and the MIC for susceptible strains, borderline results obtained with the BACTEC 460TB method, the presence of microcolonies determined using the agar proportion (AP) method, and a lack of agreement between these two testing methods. To assess the frequency of these problems, At. tuberculosis drug susceptibility data were collected in a multicenter study involving four laboratories. Resistant, borderline, and susceptible isolates were shared among the laboratories to measure interlaboratory test agreement. Half of isolates determined by BACTEC 460TB to be resistant were determined to be susceptible by the AP method. Isolates determined to be resistant to EMB by both BACTEC 460TB and AP methods were almost always resistant to isoniazid. Results from isolates tested by the BACTEC 460TB method with an EMB concentration of 3.75 mug/ml in addition to the standard 2.5 mug/ml did not show improved agreement by the AP method. While these results do not indicate that the AP method is more accurate than the BACTEC 4601,13 method, laboratories should not report EMB monoresistance based on BACTEC 460TB results alone. Monoresistance to EMB should only be reported following confirmation by the All method. Microcolonies could not be confirmed as resistant by the BACTEC 460TB method or by repeat testing with the All method and do not appear to be indicative of resistance.