Phage Resistance in Multidrug-Resistant Klebsiella pneumoniae ST258 Evolves via Diverse Mutations That Culminate in Impaired Adsorption
Phage Resistance in Multidrug-Resistant Klebsiella pneumoniae ST258 Evolves via Diverse Mutations That Culminate in Impaired Adsorption
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DOI：
10.1128/mbio.02530-19
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发表时间：
2020-01-01
期刊：
影响因子：
6.4
通讯作者：
Adhya, Sankar
中科院分区：
文献类型：
--
作者：
Hesse, Shayla;Rajaure, Manoj;Adhya, Sankar
噬菌体抗性的进化对噬菌体治疗的功效构成了不可避免的威胁。对噬菌体组合的战略选择对耐药性施加高遗传障碍和/或高补偿适应成本可能会减轻这种威胁。然而，为了使这种策略有效，噬菌体抗性的进化必须受到充分的限制以保持一致。在这项研究中，我们分离了能够感染改良肺炎克雷伯菌临床分离株的裂解噬菌体，并鉴定了总共 57 个噬菌体抗性突变体，这些突变体是从长期体外共培养中进化而来的。单噬菌体抗性和双噬菌体抗性突变体是从在肉汤或平板上生长的独立进化的复制共培养物中分离出来的。在相同条件下针对相同噬菌体进化的抗性分离株中，赋予抗性的突变发生在不同的基因中，但在每种情况下，这些基因的假定功能都集中在特定细胞表面结构的合成或组装周围。所有抗性突变体均表现出噬菌体吸附受损，这有力地表明这些细胞表面结构充当噬菌体受体。针对不同宿主受体的噬菌体组合降低了耐药性的发生率，而相反，含有两种针对同一受体的噬菌体的三噬菌体混合物增加了耐药性的发生率（相对于其双噬菌体、非冗余受体靶向对应物）。总之，这些数据表明，噬菌体抗性突变体的实验室表征是帮助优化治疗性噬菌体选择和混合物设计的有用工具。 重要性 噬菌体（噬菌体）的治疗用途正在引起人们对难以治疗的感染的新兴趣。噬菌体抗性是噬菌体治疗的主要限制之一。因此，制定有效的战略来避免或减轻其影响至关重要。体外噬菌体抗性的表征可能是评估噬菌体抗性群体出现的相对可能性、抗性突变体最可能的表型以及某些噬菌体混合物组合在增加或减少抗性遗传屏障方面的作用的重要第一步。如果这些信息赋予体内预测能力，那么噬菌体抗性突变体及其体外进化的常规研究应该是提高人类噬菌体治疗的安全性和有效性的宝贵手段。
The evolution of phage resistance poses an inevitable threat to the efficacy of phage therapy. The strategic selection of phage combinations that impose high genetic barriers to resistance and/or high compensatory fitness costs may mitigate this threat. However, for such a strategy to be effective, the evolution of phage resistance must be sufficiently constrained to be consistent. In this study, we isolated lytic phages capable of infecting a modified Klebsiella pneumoniae clinical isolate and characterized a total of 57 phage-resistant mutants that evolved from their prolonged coculture in vitro. Single- and double-phage-resistant mutants were isolated from independently evolved replicate cocultures grown in broth or on plates. Among resistant isolates evolved against the same phage under the same conditions, mutations conferring resistance occurred in different genes, yet in each case, the putative functions of these genes clustered around the synthesis or assembly of specific cell surface structures. All resistant mutants demonstrated impaired phage adsorption, providing a strong indication that these cell surface structures functioned as phage receptors. Combinations of phages targeting different host receptors reduced the incidence of resistance, while, conversely, one three-phage cocktail containing two phages targeting the same receptor increased the incidence of resistance (relative to its two-phage, nonredundant receptor-targeting counterpart). Together, these data suggest that laboratory characterization of phage-resistant mutants is a useful tool to help optimize therapeutic phage selection and cocktail design.IMPORTANCE The therapeutic use of bacteriophage (phage) is garnering renewed interest in the setting of difficult-to-treat infections. Phage resistance is one major limitation of phage therapy; therefore, developing effective strategies to avert or lessen its impact is critical. Characterization of in vitro phage resistance may be an important first step in evaluating the relative likelihood with which phage-resistant populations emerge, the most likely phenotypes of resistant mutants, and the effect of certain phage cocktail combinations in increasing or decreasing the genetic barrier to resistance. If this information confers predictive power in vivo, then routine studies of phage-resistant mutants and their in vitro evolution should be a valuable means for improving the safety and efficacy of phage therapy in humans.