Antimicrobians

Antimicrobians are agents that kill or inhibit microorganisms, including bacteria, fungi, viruses, and parasites. They are used to treat active infections and, in some cases, to prevent infection. The term covers a broad range of substances, from therapeutic drugs such as antibiotics, antifungals, antivirals, and antiparasitics to topical antiseptics and environmental disinfectants. In clinical practice, antimicrobial drugs are usually systemic or localized, while antiseptics and disinfectants are applied to skin or surfaces to reduce microbial burden.

Mechanisms of action vary by class. Some antimicrobials weaken or destroy the microbial cell wall, others inhibit protein synthesis or nucleic acid synthesis, disrupt metabolic pathways, or compromise membrane integrity. They can be bactericidal (killing organisms) or bacteriostatic (inhibiting growth). Spectrum ranges from narrow, targeting specific groups, to broad, affecting many organisms. Choice depends on the suspected or confirmed pathogen, site of infection, patient factors, and potential drug interactions.

Resistance and stewardship are major considerations. Microorganisms can acquire resistance through mutations, enzyme production, efflux pumps, or biofilm formation, and misuse or overuse of antimicrobials accelerates this process. Antimicrobial stewardship aims to optimize agent selection, dosing, and duration to maximize efficacy while minimizing resistance, side effects, and ecological impact. Infection prevention, surveillance, and appropriate prescribing are integral to modern practice.

Examples include penicillins and cephalosporins (antibiotics), azoles and echinocandins (antifungals), acyclovir and other antivirals (virals), and chloroquine or primaquine (antiparasitics). Safety considerations encompass allergic reactions, organ toxicity, drug interactions, and the need for careful use in vulnerable populations.