Table 1.
Strains used in this study and host range of phages ɸAPCEc01, ɸAPCEc02 and ɸAPCEc03.
Fig 1.
Transmission electron micrographs of E. coli phages ɸAPCEc01 (a), ɸAPCEc02 (b), and ɸAPCEc03 (c).
The thin arrows in micrograph c indicate the 3 flexible fibres attached to the distal end of the phage tail. The terminal baseplate spike in c is illustrated by the thick arrow.
Table 2.
Dimensions of the three E. coli phages isolated in this study.
Fig 2.
One-step growth curves of phages ɸAPCEc01 (a), ɸAPCEc02 (b), and ɸAPCEc03 (c) with E. coli strain DPC6051 in LB broth at 37°C.
Table 3.
Genome features of phages ɸAPCEc01, ɸAPCEc02 and ɸAPCEc03.
Fig 3.
BLAST Ring Image Generator representation of phage ɸAPCEc01 (a), ɸAPCEc02 (b), and ɸAPCEc03 (c) genomes.
The innermost rings show the GC content (black) and GC skew (purple: GC skew[-]; green: GC skew[+]). For each comparison using BRIG, the longest phage genome was used as a reference, and its name is indicated in the middle of the rings. The circles represent the genomes of the phages compared to this reference including the phages described in this study.
Fig 4.
The optical density (OD600nm) was measured after 24 h of contact between E. coli strain DPC6051 and phage ɸAPCEc01 (a), phage ɸAPCEc02 (b), phage ɸAPCEc03 (c), and a cocktail of the three phages (d). *** p<0.001, * p<0.05.
Fig 5.
Effect of single phages ɸAPCEc01 (a), ɸAPCEc02 (b), ɸAPCEc03 (c), and a three-phage cocktail (d) on a 24 h-biofilm formed by E. coli strain DPC6051, after 24 h (■) and 48 h () of contact between phage and biofilm.
Biofilm activity was assessed by OD492nm measures after treatment with XTT supplemented with menadione. ***p<0.001; **p<0.01; *p<0.05.
Fig 6.
Effect of a combination of ciprofloxacin HCl and phages ɸAPCEc01, ɸAPCEc02, and ɸAPCEc03, alone or in cocktail, on the growth of E. coli strain DPC6051.
Each condition was tested in triplicate. Bacterial counts were performed after 24 h of incubation, with a detection threshold of 20 cfu/ml. *** p<0.001, ** p<0.01, * p<0.05.