Global Emergence of Multidrug-resistant Bacteria: Mechanisms, Challenges, and Public Health Implications

ABSTRACT This review evaluates the emergence, resistance mechanisms, and global impact of multidrug-resistant (MDR) bacterial pathogens. It analyzes major resistance trends, clinical implications, and current containment strategies through a systematic review of literature between 2020 and 2025 from Scopus, Pub Med, and Web of Science. Key mechanisms identified include genetic mutations, horizontal gene transfer, and efflux pump overexpression. MDR prevalence and impact were assessed using WHO data and meta-analyses. A significant rise in MDR organisms such as methicillin-resistant Staphylococcus aureus (MRSA), carbapenem-resistant Enterobacteriaceae, multidrug-resistant E. coli, K. pneumoniae, and A. baumannii was observed. These pathogens show resistance via β-lactamase production, plasmid transfer, and efflux pumps. MDR infections cause 1.27 million deaths annually, with LMICs bearing 70% of the burden and global healthcare costs exceeding $55 billion. The misuse of antibiotics in healthcare and agriculture accelerates resistance. Promising responses include stewardship programs, phage therapy, CRISPR-based methods, and global policy initiatives. Urgent, coordinated action is required to strengthen surveillance, optimize antibiotic use, and develop innovative therapies.