Multiple choice Which of the following microorganisms is associated with comedones? Staphylococcus aureus Haemophilus parainfluenzae Corynaebacterium Propionibacterium acne Reveal answer Fill a bubble to check yourself D Correct answer Explanation Comedones are associated with Propionibacterium acne. This bacterium causes acne vulgaris. In the first stage of the disease, comedones are formed where distension of the glands is caused by an accumulation of sebum, hair and bacteria.