Profiling of rpoB Mutations and MICs for Rifampin and Rifabutin in Mycobacterium tuberculosis
Profiling of rpoB Mutations and MICs for Rifampin and Rifabutin in Mycobacterium tuberculosis
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DOI：
10.1128/jcm.00691-14
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发表时间：
2014-06-01
影响因子：
9.4
通讯作者：
Mehaffy, C.
中科院分区：
文献类型：
--
作者：
Jamieson, F. B.;Guthrie, J. L.;Mehaffy, C.
结核分枝杆菌对利福平(RIF)和利福平(RFB)的耐药性与rpoB基因81bp区域(RIF耐药决定区[RRDR])的突变有关。以前的研究表明，该区域的某些突变更有可能产生高水平的RIF耐药性，而其他突变可能在表型敏感的分离株中发现。在这项研究中，我们试图确定32株多药耐药(MDR)、4株RIF单耐药和5株敏感结核分枝杆菌临床分离株中RIF和RFB的MIC与rpoB RRDR突变的关系。用MGIT 960系统测定MIC。通过Sanger测序确定rpoB RRDR的突变。突变S531L(S第531位改为L)、S531W、H526Y、H526D和双突变D516A-R529Q的rpoB蛋白与RIF和RFB的高MIC相关。携带突变L511P、H526L、H526N和D516G-S522L的5株分离株对RIF易感。一些突变与对RIF的耐药性和对RFB(F514FF、D516V和S522L)的敏感性有关。对两株无rpoB RRDR突变的MDR分离株进行全基因组测序，发现RRDR外有一个突变(V146F；RIF MIC为50微克/毫升)。在第二个分离株中发现的多态在RIF耐药性中的意义需要进一步探讨。我们的研究进一步建立了结核分枝杆菌RIF和RFB基因突变与MICs之间的相关性。在对RIF和RFB敏感的分离株中发现了几个rpoB突变。这些发现的临床意义需要进一步探讨。在此之前，建议采用表型和分子检测相结合的方法进行药敏试验。
Resistance to rifampin (RIF) and rifabutin (RFB) in Mycobacterium tuberculosis is associated with mutations within an 81-bp region of the rpoB gene (RIF resistance-determining region [RRDR]). Previous studies have shown that certain mutations in this region are more likely to confer high levels of RIF resistance, while others may be found in phenotypically susceptible isolates. In this study, we sought to determine the relationship between the MICs of RIF and RFB and rpoB RRDR mutations in 32 multidrug-resistant (MDR), 4 RIF-monoresistant, and 5 susceptible M. tuberculosis clinical isolates. The MICs were determined using the MGIT 960 system. Mutations in the rpoB RRDR were determined by Sanger sequencing. RpoB proteins with mutations S531L (a change of S to L at position 531), S531W, H526Y, and H526D and the double mutation D516A-R529Q were associated with high MICs for RIF and RFB. Five isolates carrying the mutations L511P, H526L, H526N, and D516G-S522L were found to be susceptible to RIF. Several mutations were associated with resistance to RIF and susceptibility to RFB (F514FF, D516V, and S522L). Whole-genome sequencing of two MDR isolates without rpoB RRDR mutations revealed a mutation outside the RRDR (V146F; RIF MIC of 50 mu g/ml). The implications of the polymorphisms identified in the second of these isolates in RIF resistance need to be further explored. Our study further establishes a correlation between the mutations and the MICs of RIF and, also, RFB in M. tuberculosis. Several rpoB mutations were identified in RIF-and RFB-susceptible isolates. The clinical significance of these findings requires further exploration. Until then, a combination of phenotypic and molecular testing is advisable for drug susceptibility testing.