Bacteriophage therapy for multidrug- and extensively drug-resistant Acinetobacter baumannii: isolation,...

Acinetobacter baumannii is a WHO critical-priority pathogen that causes life-threatening healthcare-associated infections, particularly in intensive care units (ICUs). In South Asia and the Middle East, multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains are common and resistance to cephalosporins is 87-100% and to carbapenems 78-90%, leaving only a few remaining therapeutic options like colistin, tigecycline, and polymyxin B.

This review aimed to provide an overview of the current knowledge regarding the epidemiology, virulence factors, and resistance mechanisms of MDR/XDR A. baumannii globally and within Pakistan, with particular emphasis on therapeutic approach using bacteriophages as potential alternative to conventional antimicrobial therapy. This review is distinguished from prior publications on A. baumannii phage therapy by its integration of Pakistan-specific epidemiological and phage-isolation data with a critical, comparative synthesis of phage-antibiotic synergy evidence and emerging (2024-2026) clinical and preclinical literature.

This review synthesizes current isolation, purification, and genomic/proteomic characterization methods for A. baumannii-targeting bacteriophages, and critically evaluates phage-antibiotic synergy (PAS), in vivo and compassionate-use clinical evidence, and translational and regulatory barriers, alongside emerging alternative antimicrobial strategies and surveillance gaps in resource-limited settings such as Pakistan.

In conclusion, combination therapy of phage and antibiotics, especially sequential phage-colistin therapy, is a promising strategy against MDR/XDR A. baumannii infections. There are several key priorities for the future to consider, such as the establishment of national phage banks, development of standardized phage susceptibility testing (phagograms), and the integration of phage therapy into antimicrobial stewardship and surveillance frameworks, especially in high-burden, resource-limited settings such as Pakistan.