During the spore forming stage, bacteria are resistant to many disinfectants. Which statement is correct?

• A. The spore forming stage makes bacteria resistant to many disinfectants
• B. They are easily killed by disinfectants
• C. They never form spores
• D. They cannot reproduce

Answer: (A)

Spore formation creates a highly protective, dormant state that shields bacteria from disinfectants. In this stage the organism develops a tough spore coat, a cortex layer, low water content, and protective compounds like dipicolinic acid, all of which greatly reduce chemical penetration and metabolic activity. Because many disinfectants rely on attacking active cells or disrupting metabolism, spores survive treatments that would kill vegetative bacteria. That’s why the correct statement is that the spore-forming stage makes bacteria resistant to many disinfectants.

Remember, spore formation is a survival response for some bacteria, not a method of reproduction. Spore-formers can still reproduce by ordinary binary fission when conditions are favorable, and not all bacteria form spores.