Sequential phage delivery can outperform cocktails by delaying cross-resistance evolution

Antimicrobial resistance has renewed interest in bacteriophage therapy, yet bacterial evolution frequently undermines treatment efficacy. Combination phage therapy is commonly implemented as simultaneous phage cocktails, but whether this is optimal remains in question. Here, we experimentally compare simultaneous versus sequential administration of two phages, an evolved λ called ‘λtrn’ and T2, on Escherichia coli K-12 under controlled laboratory conditions. Across replicated experiments, treatment outcome depended strongly on delivery strategy, dosing order, and timing. Contrary to expectations, sequential delivery consistently achieved greater and more sustained bacterial suppression than simultaneous cocktails, although only when T2 initiated the sequence. Phenotypic assays revealed that treatment differences are driven by the accessibility and timing of cross-resistance evolution. λtrn-First treatments rapidly selected for cross-resistant bacteria prior to exposure to the second pha..., , # Sequential phage delivery can outperform cocktails by delaying cross-resistance evolution Dataset DOI: [10.5061/dryad.stqjq2chf](https://doi.org/10.5061/dryad.stqjq2chf) ## Description of the data and file structure Here, we experimentally compare simultaneous versus sequential administration of two phages, an evolved λ called ‘λtrn’ and T2, on *Escherichia coli* K-12 under controlled laboratory conditions. Bacteria and phage were cocultured for 14 days, with phages administered simultaneously (cocktail) or sequentially. ### Files and variables #### File: Figure6_Table_S16.R **Description:** R code used to generate figures 6A-C. To import data, save as an Excel file and import using R Studio's Excel import function, or import .csv file using the \"read.csv\" function. 1. Figure 6A: which shows Growth curves showing bacterial density (OD~600~) measured over 24 hours for individual λ-First isolates plotted alongside the wild-type (WT; black). 2. Figure 6B: Growth curves showing ..., ,抗菌药物耐药性（antimicrobial resistance）再度唤起了学界对噬菌体疗法（bacteriophage therapy）的研究兴趣，但细菌的进化过程往往会削弱该疗法的治疗效果。目前联合噬菌体疗法通常采用同时施用的噬菌体混合制剂（phage cocktails）策略，但其是否为最优方案仍存疑。本研究在可控实验室条件下，针对大肠杆菌K-12（Escherichia coli K-12），对两种噬菌体——一株经进化的λ噬菌体命名为“λtrn”与T2噬菌体——的同时施用与序贯施用方案开展了实验对比。在重复实验中，治疗效果显著依赖于给药策略、给药顺序与给药时机。与预期相悖的是，仅当以T2噬菌体启动序贯给药流程时，序贯施用方案始终比同时施用的混合制剂实现了更强且更持久的细菌抑制效果。表型分析实验显示，不同给药方案的疗效差异由交叉耐药进化（cross-resistance evolution）的可及性与发生时机所驱动。先施用λtrn的处理组会在接触第二种噬菌体前快速筛选出交叉耐药细菌…… # 序贯噬菌体给药可通过延迟交叉耐药进化实现优于混合制剂的治疗效果 数据集DOI：[10.5061/dryad.stqjq2chf](https://doi.org/10.5061/dryad.stqjq2chf) ## 数据与文件结构说明 本研究在可控实验室条件下，针对大肠杆菌K-12（Escherichia coli K-12），对两种噬菌体——一株经进化的λ噬菌体命名为“λtrn”与T2噬菌体——的同时施用与序贯施用方案开展了实验对比。实验中将细菌与噬菌体共培养14天，噬菌体采用同时施用（混合制剂）或序贯施用两种方式给药。 ### 文件与变量 #### 文件：Figure6_Table_S16.R **文件说明**：用于生成图6A-C的R代码。若需导入数据，可将其保存为Excel文件后通过RStudio的Excel导入功能加载，或使用`read.csv`函数导入.csv格式文件。 1. 图6A：展示了单独分离的λtrn先处理组菌株的生长曲线，其中以24小时内测得的细菌密度（光密度OD600）为指标，并与野生型菌株（WT，黑色曲线）一同绘制。 2. 图6B：生长曲线展示……