Antimicrobial resistance is the ability of microbes to survive drugs that once killed them, and it has become a major global health threat. Bacteria, viruses, fungi and parasites evolve under the selective pressure of antimicrobial use. Random mutations or the uptake of resistance genes can alter drug targets, reduce drug uptake, pump drugs out of the cell, or inactivate them chemically. These traits then spread through clonal expansion and horizontal gene transfer, especially via plasmids.

Research highlights that misuse and overuse of antibiotics in human medicine, agriculture and animal husbandry accelerate this process. In many settings antibiotics are prescribed for viral infections, used without prescription, or employed as growth promoters in livestock. Poor infection control, inadequate sanitation and global travel help resistant strains move rapidly between communities and across borders.

Clinically important examples include methicillin resistant Staphylococcus aureus, multidrug resistant tuberculosis, extended spectrum beta lactamase producing Enterobacterales and carbapenem resistant organisms. These pathogens limit treatment options, increase healthcare costs, prolong hospital stays and raise mortality. Resistance in malaria parasites, HIV and influenza viruses, and fungal pathogens such as Candida further complicates therapy.

Current research pursues several strategies. These include surveillance systems that track resistance patterns, stewardship programs to optimize prescribing, and infection prevention through vaccination, hygiene and water sanitation. Scientists are exploring new antibiotics, combinations of existing drugs, antimicrobials targeting virulence rather than survival, bacteriophages, and agents that block resistance mechanisms such as efflux pumps or beta lactamases. Progress depends on coordinated global policy, investment in diagnostics and drugs, and public education to preserve antimicrobial effectiveness.