This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Misc., Subject name: Microbiology
Which of the following is the main colonizer of sebaceous gland: (PGI June 2007) 
Select and explain. 
A. Propionic bacterium acnes, B. Diphtheria, C. Streptopyogens, D. Staph aureus
A: Propionic bacterium acnes
Answer: A: Propionic bacterium acnes 
Explanation: Ans. A (Propionic bacterium acnes) Propiniobacterium acnesQ a normal commensalQ'of the pilosebaceous apparatus, plays an important role in pathogenesis of acne. Other organisms implicated include P. granulosum, Malassezia furfur and coagulase negative micrococci"- Neena Khanna 3rd/9SFig- Etiology- of Acne vulgaris"Anaerobic diphtheroids (Corynebacterium acnes) Q are most common in areas rich in sebaceous glands. These are now classified as Propionibacterium acnesQ and as P granulosum. P acnes are seen eight times more frequently than P granulosum. Other microbial group isolated from sebaceous gland are Staphylococcus and Pityrosporum species"- Dermatology by Moschella & Hurley 3nd /68