Nacubactam Enhances Meropenem Activity against Carbapenem-Resistant Klebsiella pneumoniae Producing KPC
Nacubactam Enhances Meropenem Activity against Carbapenem-Resistant Klebsiella pneumoniae Producing KPC
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DOI：
10.1128/aac.00432-19
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发表时间：
2019-08-01
影响因子：
4.9
通讯作者：
Bonomo, Robert A.
中科院分区：
文献类型：
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作者：
Barnes, Melissa D.;Taracila, Magdalena A.;Bonomo, Robert A.
耐碳青霉烯类肠杆菌科细菌(CRE)对大多数抗生素都有耐药性，使CRE感染极难用现有的药物治疗。克雷伯氏菌碳青霉烯酶(KPC-2和KPC-3)是美国CRE中最主要的碳青霉烯酶。那库巴坦是一种桥联二氮双环辛烷(DBO)β-内酰胺酶抑制剂，可灭活A类和C类β-内酰胺酶，并显示出内在的抗生素和β-内酰胺类抗肠杆菌科“增强剂”活性。在这项研究中，我们检测了一组携带bla(KPC-2)或blA(KPC-3)的耐美罗培南肺炎克雷伯菌；美罗培南-那库巴坦恢复了敏感性。在测试产生KPC-2变异体的同基因大肠杆菌(K73、S130、R164、E166、N170、D179、K234、e276等)时，K234R变异体与产生KPC-2的菌株相比，增加了美罗培南的MIC，但不增加美罗培南的MIC。相应地，那库巴坦抑制Kpc-2(表观K-I[K-iAPP]=31+/-3muM)比K234R变异体(K-I app=270+/-27muM)更有效，并显示出更快的酰化速率(k(2)/K)，Kpc-2为5815+/-582M-1 S(-1)而K234R变异体为247+/-25M-1 S(-1)。与阿维巴坦不同的是，定时质谱仪显示纳库巴坦上有一个完整的硫酸盐和一个带有K234R变体的新峰(+337Da)。对K234R变异体的分子模拟显示，显著的催化残基(即570、K73和5130)重排可能干扰Nacubactam的结合和酰化。Nacubactam的氨乙氧基尾巴与K234R变异体的活性部位形成了无效的相互作用。分子模拟和对接观察与生化分析结果一致。总体而言，美罗培南-那库巴坦联合治疗对碳青霉烯耐药肺炎克雷伯菌有效。此外，我们的数据表明，与阿维巴坦相比，那库巴坦对β-内酰胺酶的抑制是通过另一种机制进行的。
Carbapenem-resistant Enterobacteriaceae (CRE) are resistant to most antibiotics, making CRE infections extremely difficult to treat with available agents. Klebsiella pneurnoniae carbapenemases (KPC-2 and KPC-3) are predominant carbapenemases in CRE in the United States. Nacubactam is a bridged diazabicyclooctane (DBO) beta-lactamase inhibitor that inactivates class A and C beta-lactamases and exhibits intrinsic antibiotic and beta-lactam "enhancer" activity against Enterobacteriaceae. In this study, we examined a collection of meropenem-resistant K pneumoniae isolates carrying bla(KPC-2) or bla(KPC-3); meropenem-nacubactam restored susceptibility. Upon testing isogenic Escherichia coli strains producing KPC-2 variants with single residue substitutions at important Ambler class A positions (K73, S130, R164, E166, N170, D179, K234, E276, etc.), the K234R variant increased the meropenemnacubactam MIC compared to that for the strain producing KPC-2, without increasing the meropenem MIC. Correspondingly, nacubactam inhibited KPC-2 (apparent K-i [K-iapp] = 31 +/- 3 mu M) more efficiently than the K234R variant (K-i app = 270 +/-27 mu M) and displayed a faster acylation rate (k(2)/K, which was 5,815 +/- 582 M-1 s(-1) for KPC-2 versus 247 +/- 25 M-1 s(-1) for the K234R variant. Unlike avibactam, timed mass spectrometry revealed an intact sulfate on nacubactam and a novel peak (+337 Da) with the K234R variant. Molecular modeling of the K234R variant showed significant catalytic residue (i.e., 570, K73, and 5130) rearrangements that likely interfere with nacubactam binding and acylation. Nacubactam's aminoethoxy tail formed unproductive interactions with the K234R variant's active site. Molecular modeling and docking observations were consistent with the results of biochemical analyses. Overall, the meropenem-nacubactam combination is effective against carbapenem-resistant K. pneumoniae. Moreover, our data suggest that p-lactamase inhibition by nacubactam proceeds through an alternative mechanism compared to that for avibactam.