Propionibacterium acnes is commonly a contaminant in blood cultures because it is part of the normal flora of which body surface?

Propionibacterium acnes is commonly a contaminant in blood cultures because it is part of the normal flora of which body surface?

• A. Skin
• B. Mucous membranes
• C. Blood
• D. Lungs

Answer: (A)

P. acnes is a normal resident of human skin, especially in hair follicles and sebaceous glands. Because blood cultures are obtained by passing skin with a needle, skin flora can be introduced into the sample during collection. This makes P. acnes a common contaminant in blood cultures. It is not typically a resident of mucous membranes, blood, or the lungs, so those surfaces are unlikely sources of this organism in routine contamination.

P. acnes is a normal resident of human skin, especially in hair follicles and sebaceous glands. Because blood cultures are obtained by passing skin with a needle, skin flora can be introduced into the sample during collection. This makes P. acnes a common contaminant in blood cultures. It is not typically a resident of mucous membranes, blood, or the lungs, so those surfaces are unlikely sources of this organism in routine contamination.