antimicrobial

An antimicrobial is any substance or agent that kills microorganisms or inhibits their growth. Antimicrobials include antibiotics, antifungals, antivirals, and antiparasitics, as well as antiseptics and disinfectants used on living tissue or in the environment. They are used to prevent, treat, or reduce infections in humans, animals, and plants.

Antimicrobials are categorized by the type of organism they target: antibiotics for bacteria, antifungals for fungi, antivirals for viruses, and antiparasitics for parasites. They act through diverse mechanisms, such as inhibiting cell-wall synthesis, protein synthesis, or nucleic acid synthesis; disrupting membranes; or blocking metabolic pathways.

Resistance occurs when microorganisms adapt to survive exposure to an antimicrobial. It can arise from genetic mutations or from horizontal transfer of resistance genes. It is driven by overuse, misuse, and incomplete courses. Antimicrobial resistance reduces treatment effectiveness and increases morbidity and mortality, prompting stewardship, surveillance, and infection-control measures to optimize use and prevent spread.

In clinical practice, antimicrobials are used to treat infections, prevent surgical and other procedures, and in agriculture to promote growth or prevent disease. The development of new agents faces scientific and economic challenges, and researchers are exploring alternatives such as bacteriophages, vaccines, and host-directed therapies, alongside prevention and prudent use to preserve efficacy.