Fig. 1.

Individual phage and phage cocktail are able to reduce the viability of some, but not all, Klebsiella biofilms. Phage were added to biofilms either individually or combined in a cocktail (PhC) at the start (A) of biofilm formation, as a preventative, or for 5 ​h (B) to a mature Klebsiella biofilms, as described in the methods. Biofilms were analysed using the resazurin viability stain. Some individual phage were able to reduce biofilm viability when added at the start of biofilm formation (A), and in four strains the cocktail was effective when added at this point. When used on a mature biofilm (B), there was very limited effects on biofilm viability. Symbols denote significant difference (t-test); ∗ compared to positive control, ∗ denotes p value ​≤ ​0.05, ∗∗, p ​≤ ​0.01, ∗∗∗, p ​≤ ​0.001.