Engineered bacteriophages as precision antimicrobials against multidrug-resistant ESKAPE pathogens: molecular engineering strategies, clinical translation, and the crystallizing global regulatory landscape

The global antimicrobial resistance crisis, driven primarily by the ESKAPE pathogen consortium has catalyzed the translation of engineered bacteriophage therapeutics from experimental platforms to clinical-stage precision medicines. Unlike their wild-type counterparts, which are constrained by narrow host ranges, susceptibility to reticuloendothelial clearance, and limited biofilm penetrability, synthetically engineered phages exploit receptor-binding protein remodeling, phage-derived enzymatic depolymerases, CRISPR-Cas3 chromosomal shredding payloads, sequence-independent SASPject delivery vectors, and in vivo microbiome base editors to overcome the multilayered resistance arsenals of MDR ESKAPE organisms. Recent clinical development has generated human evidence across both genetically engineered phage platforms and advanced fixed phage-cocktails. Engineered programmes include CRISPR-Cas3-based LBP-EC01 and SNIPR001, while AP-SA02 represents an analytically characterized fixed multi-phage cocktail targeting Staphylococcus aureus. This review examines engineering strategies, pharmacokinetics, immune-mediated clearance, delivery challenges, clinical evidence, manufacturing, and regulatory pathways. It also discusses emerging regulatory approaches and distinctions between natural and genetically modified phage products. The literature search was conducted from January-June 2026 using PubMed, Scopus, and Google Scholar, supplemented by searches of ClinicalTrials.gov and the websites of the US-FDA and EMA. Overall, this review evaluates the translational potential of engineered phages, identifies barriers to clinical adoption, and considers future developments in precision antimicrobial therapy against multidrug-resistant pathogens.