Which of the following statements about Propionibacterium acnes is correct?

• A. It is a spore-forming bacterium responsible for tuberculosis.
• B. It is a photosynthetic bacterium that produces oxygen.
• C. It is a Gram-negative, aerobic bacterium found in soil.
• D. It is a Gram-positive, anaerobic bacterium commonly associated with acne in humans.

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the characteristics of Propionibacterium acnes by reviewing its Gram stain reaction, oxygen requirements, and typical habitat or association with human health.
2. Step 2: Recall that Propionibacterium acnes is a Gram-positive bacterium, meaning it retains the crystal violet stain and appears purple under a microscope after Gram staining.
3. Step 3: Recognize that it is anaerobic, which means it thrives in environments with little or no oxygen, distinguishing it from aerobic bacteria that require oxygen.
4. Step 4: Identify its clinical relevance, particularly its association with human skin and its role in the development of acne, rather than being a spore-forming bacterium or related to tuberculosis.
5. Step 5: Use this information to evaluate each statement and confirm that the correct description is that Propionibacterium acnes is a Gram-positive, anaerobic bacterium commonly associated with acne in humans.