What is the primary mechanism of action of alcohol-based hand sanitizers?

Correct answer: D. Denaturation of microbial proteins

• A. Oxidative mechanisms characterize hydrogen peroxide and chlorine compounds — not alcohols. Alcohol's primary action is protein denaturation.
• B. Cell wall disruption is the mechanism of beta-lactam antibiotics (penicillin) and glycopeptides (vancomycin) — not alcohols. Alcohols do not primarily target the cell wall.
• C. DNA synthesis inhibition is the mechanism of fluoroquinolones, metronidazole (anaerobes), and some antiviral drugs — not hand sanitizer alcohols.
• D. CORRECT. Alcohols (ethanol, isopropanol at 60–95% concentration) work primarily by denaturing microbial proteins. The alcohol disrupts hydrogen bonds maintaining protein structure, causing structural collapse and loss of function of essential enzymes and structural proteins. This rapidly kills bacteria, fungi, and most viruses.