How do bacteria, viruses, and fungi differ in resilience to disinfectants?

• A. All are killed by standard disinfectants.
• B. Viruses are never killed by disinfectants.
• C. Bacteria and fungi are typically killed by standard disinfectants; some viruses are more resistant; spores require high-level disinfection or sterilization.
• D. Fungi are immune to high-level disinfection.

Answer: (C)

Disinfectants don’t affect all microorganisms equally. Bacteria and fungi are typically inactivated by standard disinfectants when used at the proper strength and contact time. Viruses vary a lot: many enveloped viruses are quickly inactivated by ordinary disinfectants, but non-enveloped viruses tend to be more resistant and may survive if the product isn’t used correctly. Bacterial spores are among the most resistant forms and require higher-level disinfection or sterilization to be eliminated. So the best description is that bacteria and fungi are usually killed by standard disinfectants; some viruses are more resistant; spores require high-level disinfection or sterilization.