OmpK36-mediated Carbapenem resistance attenuates ST258 Klebsiella pneumoniae in vivo
OmpK36-mediated Carbapenem resistance attenuates ST258 Klebsiella pneumoniae in vivo
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DOI：
10.1038/s41467-019-11756-y
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发表时间：
2019-09-02
影响因子：
16.6
通讯作者：
Frankel, Gad
中科院分区：
文献类型：
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作者：
Wong, Joshua L. C.;Romano, Maria;Frankel, Gad
肺炎克雷伯菌（KP）序列型ST 258中的碳青霉烯类耐药性由碳青霉烯酶（例如KPC-2）以及主要非选择性孔蛋白OmpK 35和OmpK 36的缺失或修饰介导。然而，支持OmpK 36介导的抗性的机制以及这些变化对致病性的影响仍然未知。通过解析临床ST 258 OmpK 36变体的晶体结构，我们提供了孔收缩的直接结构证据，该孔收缩由插入环3中的二氨基酸（Gly 115-Asp 116）介导，限制了营养物质（例如乳糖）和碳青霉烯类的扩散。在KPC-2的存在下，这导致对美罗培南的MIC增加16倍。此外，Gly-Asp插入损害了含乳糖培养基中的细菌生长，并在呼吸机相关性肺炎的鼠模型中赋予显著的体内适应性成本。我们的数据表明，在医院环境中广泛使用碳青霉烯所施加的持续选择压力驱动了KP表达Gly-Asp插入突变体的扩张，尽管存在相关的适应性成本。
Carbapenem-resistance in Klebsiella pneumoniae (KP) sequence type ST258 is mediated by carbapenemases (e.g. KPC-2) and loss or modification of the major non-selective porins OmpK35 and OmpK36. However, the mechanism underpinning OmpK36-mediated resistance and consequences of these changes on pathogenicity remain unknown. By solving the crystal structure of a clinical ST258 OmpK36 variant we provide direct structural evidence of pore constriction, mediated by a di-amino acid (Gly115-Asp116) insertion into loop 3, restricting diffusion of both nutrients (e.g. lactose) and Carbapenems. In the presence of KPC-2 this results in a 16-fold increase in MIC to Meropenem. Additionally, the Gly-Asp insertion impairs bacterial growth in lactose-containing medium and confers a significant in vivo fitness cost in a murine model of ventilator-associated pneumonia. Our data suggests that the continuous selective pressure imposed by widespread Carbapenem utilisation in hospital settings drives the expansion of KP expressing Gly-Asp insertion mutants, despite an associated fitness cost.