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

抗生素耐药性的出现加上正在开发的新抗生素的匮乏 激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，在噬菌体疗法成为一种可行的治疗选择之前，仍然存在一些挑战， 包括噬菌体的宿主范围狭窄，以及对遗传动员的担忧。最新版本 治疗策略依赖于特性不佳的噬菌体的鸡尾酒，这些噬菌体与 人类的微生物群。因此，需要一种更合理的方法来治疗噬菌体。 基于具有定义的和可编程的主机特性的特征良好的组件。 细微病毒科(微微病毒科)微微病毒亚族的噬菌体很吸引人 由于它们的基因组小(&lt；20KBP)和严格的裂解生活方式，因此适合于治疗应用。 本试探性/开发性(R21)项目的总体目标是(1)了解 葡萄球菌微微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实现具有可调宿主的治疗性噬菌体的合理设计 射程。在这项提案中，我们将检验我们的中心假设，即微小病毒受体结合蛋白 结构与寄主细胞壁磷壁酸组成有关。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相结合- 以基因组编辑为基础，通过三个具体目标： (1)确定葡萄球菌微小病毒附着宿主的遗传基础； (2)确定微小病毒宿主范围和特异性的结构决定因素；以及 (3)改变寄主范围的工程噬菌体。 这项工作将建立一个预测框架，以确定病原体对 一组特定的微微病毒。通过这样做，这项研究将为Rational提供一个通用的工具包 设计具有预先确定的宿主特异性的针对致病葡萄球菌的治疗性噬菌体。 这一新方法也可广泛应用于其他革兰氏阳性病原体的靶向。

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.