Beyond Antibiotics: Emerging Therapeutic Strategies, Innovations, and Sustainable Pathways to Combat Antimicrobial Resistance in the 21st Century

Abstract

Antimicrobial resistance (AMR) is a major global health threat that erodes the effectiveness of antibiotics and increases morbidity, mortality, and healthcare costs. Updated forecasts project that bacterial AMR could directly cause approximately 39 million deaths between 2025 and 2050, with annual deaths rising from 1.14 million in 2021 to an estimated 1.91 million in 2050; earlier economic modelling placed the cumulative cost of unchecked resistance at up to 100 trillion United States dollars. These figures underscore the need for sustainable alternatives to conventional antibiotics. This review synthesizes current evidence on non-antibiotic strategies, including bacteriophages, antimicrobial peptides, CRISPR-based antimicrobials, microbiome modulation, host-directed therapies, nanotechnology, and artificial-intelligence-driven drug discovery. We searched more than one hundred peer-reviewed studies, clinical trial reports, primary epidemiological analyses, and international policy and regulatory documents to evaluate therapeutic mechanisms, clinical progress, and implementation barriers, with particular attention to which strategies suit personalized, patient-specific application and which are more amenable to standardized mass production. Bacteriophages and antimicrobial peptides show potent broad-spectrum activity with reduced resistance selection pressure, CRISPR-based approaches enable precise pathogen targeting, and microbiome therapies restore colonization resistance. Clinical translation, however, is hindered by inconsistent regulatory frameworks, limited manufacturing scalability, incomplete safety profiles, and constrained funding in low-resource settings. Mitigating the AMR crisis will require a coordinated, multidisciplinary response grounded in the One Health paradigm, emphasizing antimicrobial stewardship, equitable global access to emerging therapeutics, and sustained investment in translational research.