MECHANISMS OF ANTIMICROBIAL RESISTANCE IN CLINICALLY SIGNIFICANT BACTERIAL PATHOGENS: MOLECULAR BASIS, EPIDEMIOLOGICAL TRENDS, DETECTION METHODS, AND THERAPEUTIC COUNTERMEASURES

Antimicrobial resistance (AMR) represents one of the most urgent global public health crises of the twenty-first century, threatening to reverse a century of advances in infectious disease medicine. The World Health Organization estimates that drug-resistant infections directly caused 1.27 million deaths in 2019 and contributed to 4.95 million deaths globally, with projections suggesting AMR could claim 10 million lives annually by 2050 if current trends continue unchecked. The emergence and dissemination of multidrug-resistant (MDR), extensively drug-resistant (XDR), and pandrug-resistant (PDR) bacterial pathogens—particularly the ESKAPE organisms (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.)—has dramatically narrowed the available therapeutic arsenal for severe nosocomial and community-acquired infections.