Fig. 2.

Functional diversity increases the efficacy of phage combinations. Efficacy of phage combinations with low functional diversity (FD=1), where all phages target either LPS (a) or Type IV pilus (b), and phage combinations with high functional diversity (FD=2) which include phages targeting both the LPS and Type IV pilus (c). Efficacy is measured as suppression of bacterial growth by phages relative to phage-free populations; mean values (±sd) are shown in black, with raw data in grey to show the distribution of data points. The dotted line indicates the theoretical maximum reduction (i.e. no bacterial growth detected). Linear regression equations relate to the relationship between phage richness ( x ) and efficacy ( y ); note that for (c), an asymptotic exponential model (shown in grey) better explains this relationship (AIC _{linear model}=205; AIC _{asymptotic model}=(−)1190).