Genotyping and Pharmacokinetics in the HIV/MDR-TB epidemic of Eastern Siberia

描述(申请人提供)：东西伯利亚伊尔库茨克州的艾滋病毒/多药耐药结核病(MDR-TB)疫情可以说是世界上最严重的。我们发现，在伊尔库茨克结核病诊疗所，所有艾滋病毒和原发耐多药结核病患者(以前没有结核病治疗病史)都在住院治疗期间死亡。我们还发现，基因耐药突变只部分解释了伊尔库茨克普遍存在的表型耐药程度。次优的血清抗结核药物浓度放大了这种表型耐药性，我们在其他环境中的工作已经证明了优化药物敏感结核病的药代动力学的重要性。用于治疗耐多药结核病的药物缺乏在抗结核/抗逆转录病毒药物浓度方面的这种基础工作，在艾滋病毒感染人群中也是如此。此外，我们还发现，伊尔库茨克的艾滋病毒感染与北京结核分枝杆菌的北京耐药基因有关，但在结核分支杆菌北京MIT17亚型的患者中，死亡率更高。因此，我们假设伊尔库茨克艾滋病毒/结核病的高早期死亡率是以下因素综合作用的结果：(1)复杂的多药耐药和广泛耐药(XDR)--结核病诊断和治疗不彻底，(2)抗结核/抗逆转录病毒药代动力学不佳，导致疗效低，(3)高传播和强毒力结核分支杆菌亚系循环增加。我们将通过对伊尔库茨克结核病诊所开始治疗的HIV感染患者进行抗结核和抗逆转录病毒药物的药代动力学采样来研究这些假设。我们还将在伊尔库茨克艾滋病中心对新感染抗逆转录病毒的患者进行强化病例发现。他们的痰将接受常规培养和药敏试验的结核杆菌(GeneXpert)和阳性标本的筛查，然后与定量药敏试验(MIC试验)进行比较，对耐药突变进行测序，然后进行亚系鉴定和传播性分析的基因分型。这项提议将利用与流行病学和微生物学研究所/俄罗斯医学科学院以及伊尔库茨克结核病研究所与弗吉尼亚大学的密切合作。我们汇集了来自俄罗斯和美国的艾滋病毒/结核病专家团队，他们在结核病基因分型(伊尔库茨克)、结核病分子诊断和测序(伊尔库茨克/弗吉尼亚大学)以及艾滋病毒/结核病药代动力学(弗吉尼亚大学)方面拥有长期经验。该提案的完成将提供更好的诊断战略和初步治疗方案，以对抗这一双重流行病的早期和压倒性死亡。

DESCRIPTION (provided by applicant): The HIV/multidrug-resistant tuberculosis (MDR-TB) epidemic in the Irkutsk oblast of Eastern Siberia is arguably the most severe in the world. We have found that in the Irkutsk TB Dispensary, the referral hospital for the oblast, all patients wih HIV and primary MDR-TB (no prior history of TB treatment) died during the inpatient phase of treatment. We have also found that genotypic drug-resistance mutations only partially explain the extent of phenotypic resistance that is so widespread in Irkutsk. Suboptimal serum anti-TB drug concentrations amplify such phenotypic resistance and our work in other settings has demonstrated the importance of optimizing pharmacokinetics for drug-susceptible TB. Such foundational work in anti- TB/antiretroviral drug concentrations is lacking for drugs used in the treatment of MDR-TB, and absent in the HIV-infected population. Furthermore, we have found that HIV infection in Irkutsk to be associated with the Beijing TB genotype, commonly found to be MDR, but that mortality was more frequent in those with the M. tuberculosis sublineage Beijing MIT17. Thus taken together we hypothesize that the high early HIV/TB mortality in Irkutsk is due to a combination of (1) complex MDR and extensively drug resistant (XDR)-TB that is incompletely diagnosed and incompletely treated, (2) poor anti-TB/antiretroviral pharmacokinetics that lead to low efficacy and (3) increased circulation of hyper-transmissible and virulent M. tuberculosis sublineages. We will investigate these hypotheses by performing pharmacokinetic sampling of anti-TB and antiretroviral medications in HIV-infected patients initiating therapy at Irkutsk TB Dispensary. We will also perform intensified case-finding among antiretroviral na¿ve patients at the Irkutsk AIDS Centre. Their sputum will be screened for TB (GeneXpert) and positive specimens subjected to conventional methods of culture and drug-susceptibility testing, followed by comparison to quantitative susceptibility (MIC testing), sequencing for drug-resistance mutations, and then genotyping for sublineage identification and transmissibility analysis. This proposal will leverage a strong collaboration with the Institute Epidemiology and Microbiology/Russian Academy of Medical Sciences and the Irkutsk TB Dispensary with the University of Virginia. We bring together a team of HIV/TB experts from Russia and the U.S.A. with longstanding experience in TB genotyping (Irkutsk), molecular diagnostics and sequencing for TB (Irkutsk/University of Virginia) and HIV/TB pharmacokinetics (University of Virginia). Completion of the proposal will inform better diagnostic strategies and initial therapeutic regimens to combat the early and overwhelming mortality of this dual epidemic.