Makerere University, Department of Medical Microbiology, Mycobacteriology (BSL-3) Laboratory, Kampala, Uganda.
PLoS One. 2018 Jun 28;13(6):e0199638. doi: 10.1371/journal.pone.0199638. eCollection 2018.
Although Sensititre Mycobacterium tuberculosis (MYCOTB) plate offers both drug susceptibility testing (DST) and minimum inhibitory concentration (MIC) results, it has not been evaluated against both Lowenstein Jensen (LJ) and Middlebrook 7H10 (MB7H10) DST methods at standard critical concentrations.
We analyzed 76 M. tuberculosis isolates consisting of 54 isolates from the Uganda National TB drug resistance survey done December 2009-February 2011 and 22 isolates from the World Health Organization External Quality Assessment panel for the year 2011. All isolates were tested for LJ, MB7H10 and MYCOTB plate based DSTs for streptomycin, isoniazid, rifampicin and ethambutol anti-tuberculosis drugs. The agreement of MB7H10 with LJ and accuracy of MYCOTB plate using either LJ-DST or MB7H10 as a reference standard were determined.
The agreement (kappa) of MB7H10 with LJ was; 0.687 for rifampicin, 0.498 for isoniazid, 0.275 for streptomycin and 0.082 for ethambutol which as almost similar when compared with MYCOTB plate. The sensitivity (95% confidence interval; CI) of MYCOTB plate when LJ was used as a reference standard was higher for streptomycin 87.5% (81.6-98.4) followed by isoniazid 75.9% (65.1-95.6) and rifampicin 73.1% (52.2-88.4). When MB7H10 was used as reference standard, the sensitivity of MYCOTB plate improved significantly; isoniazid 96.2% (80.3-99.9), rifampicin 94.0 (83.4-98.7) and 93.8% (69.7-99.8). There was good agreement between MYCOTB plate and MB7H10; 1.00 for ethambutol, 0.959 for streptomycin, 0.915 for rifampicin and 0.778 for isoniazid.
The performance of the two culture-based reference standards for phenotypic first-line drug susceptibility testing methods, LJ and MB7H10, varied much even with acceptable MYCOTB plate MICs. There was acceptable agreement and accuracy of MYCOTB plate for drug susceptibility testing when MB7H10 was used as reference standard than with LJ-DST. Results from MIC information makes the MYCOTB plate more suitable for guiding clinicians on the choice of the most appropriate TB treatment regimen as well as limits of detection for TB drug resistance.
Sensititre 分枝杆菌（MYCOTB）板既能提供药敏试验（DST）结果，又能提供最低抑菌浓度（MIC）结果，但尚未在标准临界浓度下与 Lowenstein Jensen（LJ）和 Middlebrook 7H10（MB7H10）DST 方法进行过评估。
我们分析了 76 株结核分枝杆菌分离株，其中 54 株来自 2009 年 12 月至 2011 年 2 月进行的乌干达国家结核病耐药性调查，22 株来自 2011 年世界卫生组织外部质量评估小组。所有分离株均进行 LJ、MB7H10 和 MYCOTB 板基于 DST 的链霉素、异烟肼、利福平、乙胺丁醇抗结核药物敏感性检测。确定了 MB7H10 与 LJ 的一致性（kappa）和使用 LJ-DST 或 MB7H10 作为参考标准时 MYCOTB 板的准确性。
MB7H10 与 LJ 的一致性（kappa）分别为：利福平 0.687、异烟肼 0.498、链霉素 0.275 和乙胺丁醇 0.082，与 MYCOTB 板相似。当 LJ 作为参考标准时，MYCOTB 板的敏感性（95%置信区间；CI）较高，链霉素为 87.5%（81.6-98.4），异烟肼为 75.9%（65.1-95.6），利福平为 73.1%（52.2-88.4）。当使用 MB7H10 作为参考标准时，MYCOTB 板的敏感性显著提高；异烟肼 96.2%（80.3-99.9）、利福平 94.0%（83.4-98.7）和 93.8%（69.7-99.8）。MYCOTB 板与 MB7H10 之间有很好的一致性；乙胺丁醇 1.00、链霉素 0.959、利福平 0.915 和异烟肼 0.778。
两种基于培养的表型一线药物敏感性检测方法的参考标准，LJ 和 MB7H10，即使 MIC 结果可接受，其性能也有很大差异。与 LJ-DST 相比，当使用 MB7H10 作为参考标准时，MYCOTB 板用于药敏试验的一致性和准确性更高。MIC 信息的结果使 MYCOTB 板更适合指导临床医生选择最合适的结核病治疗方案，以及检测结核病耐药性的界限。
