Therapeutic phages against carbapenem-resistant Escherichia coli: From discovery to clinical translation

Carbapenem-resistant Escherichia coli (CREC) is difficult to treat because few antibiotics remain reliably active and phage susceptibility varies among isolates. This narrative review examines how laboratory discovery can inform therapeutic development, with attention to host-range testing, phage genomics, antibiotic combinations, cocktail selection, preclinical models, and clinical evidence. Studies involving CREC describe encouraging outcomes for selected phages and combinations in mice, but activity is highly dependent on the strain and experimental setting; durable intestinal decolonization has been harder to demonstrate. Human studies involving E. coli provide experience with feasibility and safety, yet do not establish clinical efficacy specifically against CREC. We distinguish these direct and supporting evidence streams and discuss bacterial resistance, immune neutralization, endotoxin control, manufacturing, and dosing. Genome-informed matching and engineered phages may improve candidate selection, but predictions require experimental confirmation. Progress toward clinical use will depend on isolate-specific activity, reproducible product quality, infection-relevant preclinical testing, and controlled studies with documented carbapenem resistance and meaningful clinical outcomes.