Figure 1.

Standard Appelmans protocol to evolve phages on multiple bacterial strains. Each column of the 96-well microtiter plate contains a 200 μL culture of a single bacterial strain. Phages are added in ten-fold dilutions across the rows. (a) Overnight growth results in cleared wells (yellow) and turbid wells (green); (b) the next round of growth is started with a pool (red outline) of successful phages (the cleared wells) and the next turbid well from all columns; (*c) our modification: add 1:10 titer-based ratio of the starting phage cocktail to the pooled cocktail to start the next growth round.