Shopping for phages? Unpacking design rules for therapeutic phage cocktails

In bacteriophage therapy, the combination of different phages into a single cocktail is of critical importance to overcome the narrow host range of single phage isolates. Today, the design of therapeutic cocktails is often akin to a black box and relies largely on intuition and (pre-)availability of isolates in local collections. Here we show that straightforward host range analysis can disclose design rules and we propose to apply/translate a data mining approach, historically applied in the field of marketing ('shopping cart analysis') to explore patterns in phage combinations. The technique is broadly applicable to host range datasets and can serve in combination with other molecular-based approaches to propose rationales for phage cocktail design.