Which statement accurately describes spore-forming bacteria and disinfection?

• A. Alcohol is ineffective against spores
• B. Ethylene oxide is ineffective against spores
• C. Glutaraldehyde is ineffective against spores
• D. Peracetic acid is ineffective against spores

Answer: (A)

Spore-forming bacteria protect their endospores with tough coatings and low water content, making them exceptionally resistant to many disinfectants. Alcohols kill by denaturing proteins and dissolving membranes, but this action doesn’t reliably penetrate or inactivate the durable spore coats. That’s why alcohol-based disinfectants aren’t dependable for spores—they’re not sporicidal. In contrast, agents designed to destroy spores—used with the right concentration and contact time—are effective. Ethylene oxide acts as a sterilant with sporicidal activity when used properly; glutaraldehyde can function as a high-level disinfectant and sporicide under appropriate conditions; and peracetic acid is a potent sporicidal agent for both surfaces and devices. So the statement about alcohol being ineffective against spores correctly describes the limitation of alcohol, while the other agents can be effective against spores if used correctly.