Fig. 4: HEPTs provide enhanced killing of colicin-sensitive E. coli in patient urine.
a Workflow for combining a phage-based companion diagnostic to identify potential HEPT responder patients presenting with E2-sensitive E. coli bacteriuria (steps 1 and 2) with subsequent ex vivo treatment (step 3) and in vitro assessment (step 4) of positive urine specimens using E2 WT or E2::colE7. b Patient urine samples (n = 39) were subjected to a bioluminescence-based (E2::nluc) reporter phage assay20 to identify E2-sensitive E. coli in the urine within 4.5 h. Urine was plated on differential agar to isolate patient strains and enumerate overall bacterial load. E. coli isolates were further tested in vitro for E2 sensitivity (plaque formation) and colicin E7 sensitivity (detailed results provided in Supplementary Fig. 3) and categorized: Category I = phage and colicin sensitive; Category II = phage-resistant, colicin-sensitive; Category III = phage-sensitive, colicin-resistant. c Time kill assays were used to assess ex vivo treatment using 109 PFU/mL E2 or E2::colE7 added to fresh urine for 24 h at 37 °C (n = 1). A similar HEPT treatment was performed in vitro on patient isolates grown in SHU with bacterial killing measured using turbidity reduction assays (technical triplicates shown as mean ± SD). Elements of (a) were created with BioRender.com. Source data are provided as a Source data file.
