Department of Clinical Bacteriology, Parasitology, Zoonoses & Geographical Medicine, University Hospital of Heraklion, Crete, Greece.
Future Microbiol. 2011 Mar;6(3):357-62. doi: 10.2217/fmb.11.8.
To determine the diagnostic accuracy of Geno Type® MTBDRplus compared with conventional proportional method (PM) drug susceptibility testing (DST) for detecting drug resistance of Mycobacterium tuberculosis (MTB) clinical isolates derived from the University Hospital of Heraklion, Crete, Greece.
All MTB clinical isolates obtained between January 2000 and May 2009 were tested prospectively using the PM DST. All isolates were also tested either prospectively (strains isolated after January 2006; n = 140) or retrospectively (January 2000-December 2005; n = 81) using MTBDRplus.
Among the 221 MTB isolates tested, 19 were resistant to isoniazid based on PM DST. The MTBDRplus assay identified 18 INH-resistant strains. Of these, 12 strains gave positive hybridization results with the mutation-specific probe katG Ser315Thr. The other six INH-resistant strains carried the mutation 15C→T in the inhA promoter region. One INH-sensitive strain, as determined by PM DST, had a katG gene mutation. The sensitivity, specificity, and positive and negative predictive values of MTBDRplus for INH were 89.5, 99.5, 94.7 and 99%, respectively. The single rifampicin-resistant strain that was also the only multidrug resistance isolate gave a positive hybridization result with the mutation-specific probe MUT1: D516V, which confers resistance to rifampicin.
Despite the advantages of MTBDRplus (turn-around time of only 1 working day) compared with PM DST, the latter is still required in every case of a MTB clinical isolate, as the molecular assay does not detect 100% of drug resistance, especially INH resistance.
确定 Geno Type® MTBDRplus 与传统比例法（PM）药物敏感性试验（DST）相比，在检测来自希腊克里特岛伊拉克利翁大学医院的结核分枝杆菌（MTB）临床分离株耐药性方面的诊断准确性。
所有 MTB 临床分离株均于 2000 年 1 月至 2009 年 5 月间采用 PM DST 进行前瞻性检测。所有分离株也分别采用前瞻性（2006 年 1 月后分离的菌株；n = 140）或回顾性（2000 年 1 月至 2005 年 12 月；n = 81）方法，采用 MTBDRplus 进行检测。
在 221 株 MTB 分离株中，19 株基于 PM DST 检测结果对异烟肼耐药。MTBDRplus 检测方法鉴定出 18 株 INH 耐药株。其中 12 株 katG Ser315Thr 突变特异性探针呈阳性杂交结果。另外 6 株 INH 耐药株inhA 启动子区域携带 15C→T 突变。PM DST 检测结果显示，1 株 INH 敏感株 katG 基因发生突变。MTBDRplus 检测 INH 的敏感性、特异性、阳性预测值和阴性预测值分别为 89.5%、99.5%、94.7%和 99%。唯一的耐利福平单药株也是唯一的耐多药株，其突变特异性探针 MUT1：D516V 呈阳性杂交结果，该突变导致对利福平耐药。
尽管 MTBDRplus（仅需 1 个工作日的周转时间）具有优势，但对于每株 MTB 临床分离株，仍需要进行 PM DST，因为分子检测并不能检测出 100%的耐药性，尤其是 INH 耐药性。
