Engineering picoviruses with defined host range to combat drug-resistant staphylococci

抗生素耐药性的出现加上缺乏正在开发的新抗生素 引发了人们对噬菌体疗法作为传染病治疗策略的新兴趣 由金黄色葡萄球菌和表皮葡萄球菌等常见病原体引起。 然而，在噬菌体疗法成为可行的治疗选择之前，仍存在一些挑战， 包括寄生范围狭窄和对基因迁移的担忧。最新 治疗策略依赖于特征不明确的药物混合物， 人体微生物组因此，需要一种更合理的噬菌体治疗方法 基于具有已定义和可编程主机特性的充分表征的组件。 短尾病毒科（picoviruses）的微小病毒亚科（Picovirinae）的噬菌体具有吸引力 由于它们的小（<20 kbp）基因组和严格的裂解生活方式，它们是治疗应用的候选物。 本探索性/开发性（R21）项目的总体目标是（1）了解 葡萄球菌微小病毒宿主范围和特异性的决定因素，以及（2）揭示规则 用于操纵这种特异性以使得能够合理设计具有可调宿主的治疗药物 范围在这项提议中，我们将测试我们的中心假设，即微病毒受体结合蛋白 结构与宿主细胞壁磷壁酸组成相关。这将通过一个 噬菌体发现和序列分析，冷冻电子显微镜和CRISPR- 基于基因组编辑，通过三个具体目标： (1)确定葡萄球菌微小病毒宿主附着的遗传基础; (2)确定微小病毒宿主范围和特异性的结构决定因素; (3)工程师修改主机范围。 这项工作将建立一个预测框架，用于确定病原体对 一组特定的微小病毒在这样做的过程中，这项研究将为理性的人提供一个多功能的工具包。 设计具有针对致病性葡萄球菌的预定宿主特异性的治疗性药物。 这种新方法也可以广泛应用于靶向其他革兰氏阳性病原体。

The emergence of antibiotic resistance combined with a paucity of new antibiotics under development have sparked a renewed interest in phage therapy as a treatment strategy for infectious diseases caused by common pathogens like Staphylococcus aureus and Staphylococcus epidermidis. However, several challenges remain before phage therapy can become a viable treatment option, including the narrow host range of the phages and concerns about genetic mobilization. Most current therapeutic strategies rely on cocktails of poorly characterized phages with uncertain interaction with the human microbiome. There is therefore a need for a more rational approach to phage therapy based on well-characterized components with defined and programmable host specificities. The bacteriophages of the Picovirinae subfamily of the Podoviridae (picoviruses) are attractive candidates for therapeutic applications due to their small (<20 kbp) genomes and strictly lytic lifestyle. The overall objectives of this exploratory/developmental (R21) project are (1) to understand the determinants for host range and specificity in staphylococcal picoviruses, and (2) to uncover the rules for manipulating this specificity to enable the rational design of therapeutic phages with tunable host range. In this proposal we will test our central hypothesis that picovirus receptor binding protein structures correlate with host cell wall teichoic acid composition. This will be accomplished through a combination of phage discovery and sequence analysis, cryo-electron microscopy, and CRISPR- based genome editing, via three specific aims: (1) Determine the genetic basis for host attachment by staphylococcal picoviruses; (2) Define the structural determinants for picovirus host range and specificity; and (3) Engineer phages with altered host ranges. This work will establish a predictive framework for determining the sensitivity of a pathogen to a specific set of picoviruses. In doing so, this research will provide a versatile toolkit for the rational design of therapeutic phages with pre-determined host specificities against pathogenic staphylococci. This novel approach can also be broadly applied to target other Gram-positive pathogens.