Watterson S A, Wilson S M, Yates M D, Drobniewski F A
Public Health Laboratory Service Mycobacterium Reference Unit, Department of Microbiology, King's College School of Medicine and Dentistry, King's College Hospital (Dulwich), London, United Kingdom.
J Clin Microbiol. 1998 Jul;36(7):1969-73. doi: 10.1128/JCM.36.7.1969-1973.1998.
Multidrug-resistant Mycobacterium tuberculosis (MDR-TB) is an emerging problem of great importance to public health, with higher mortality rates than drug-sensitive TB, particularly in immunocompromised patients. MDR-TB patients require treatment with more-toxic second-line drugs and remain infectious for longer than patients infected with drug-sensitive strains, incurring higher costs due to prolonged hospitalization. It is estimated that 90% of United Kingdom rifampin-resistant isolates are also resistant to isoniazid, making rifampin resistance a useful surrogate marker for multidrug resistance and indicating that second- and third-line drugs to which these isolates are susceptible are urgently required. Resistance in approximately 95% of rifampin-resistant isolates is due to mutations in a 69-bp region of the rpoB gene, making this a good target for molecular genotypic diagnostic methods. Two molecular assays, INNO-LiPA Rif.TB (Innogenetics, Zwijndrecht, Belgium) and MisMatch Detect II (Ambion, Austin, Tex.), were performed on primary specimens and cultures to predict rifampin resistance, and these methods were compared with the resistance ratio method. A third method, the phenotypic PhaB assay, was also evaluated in comparison to cultures in parallel with the genotypic assays. In an initial evaluation 16 of 16, 15 of 16, and 16 of 16 rifampin-resistant cultures (100, 93.8, and 100%, respectively), were correctly identified by line probe assay (LiPA), mismatch assay, and PhaB assay, respectively. Subsequently 38 sputa and bronchealveolar lavage specimens and 21 isolates were received from clinicians for molecular analysis. For the 38 primary specimens the LiPA and mismatch assay correlated with culture and subsequent identification and susceptibility tests in 36 and 38 specimens (94.7 and 100%), respectively. For the 21 isolates submitted by clinicians, both assays correlated 100% with routine testing.
耐多药结核分枝杆菌（MDR-TB）是一个对公共卫生极为重要的新出现问题，其死亡率高于药物敏感型结核病，尤其是在免疫功能低下的患者中。耐多药结核病患者需要使用毒性更大的二线药物进行治疗，并且比感染药物敏感菌株的患者具有更长时间的传染性，由于住院时间延长而产生更高的费用。据估计，英国90%的耐利福平分离株也对异烟肼耐药，这使得利福平耐药成为耐多药的一个有用替代标志物，并表明迫切需要这些分离株敏感的二线和三线药物。约95%的耐利福平分离株的耐药性是由于rpoB基因69bp区域的突变，这使其成为分子基因型诊断方法的一个良好靶点。对原始标本和培养物进行了两种分子检测，即INNO-LiPA Rif.TB（比利时兹温德雷赫特的Innogenetics公司）和错配检测II（德克萨斯州奥斯汀的Ambion公司），以预测利福平耐药性，并将这些方法与耐药率方法进行比较。还与基因型检测平行地对培养物进行比较，评估了第三种方法，即表型PhaB检测。在初步评估中，16株利福平耐药培养物中的16株（100%）、16株中的15株（93.8%）和16株中的16株（100%）分别通过线性探针检测（LiPA）、错配检测和PhaB检测被正确鉴定。随后，从临床医生处收到了38份痰液和支气管肺泡灌洗标本以及21株分离株用于分子分析。对于38份原始标本，LiPA和错配检测分别与36份和38份标本（94.7%和100%）的培养及后续鉴定和药敏试验相关。对于临床医生提交的21株分离株，两种检测与常规检测的相关性均为100%。
