<prompt> Which of the following is the main colonizer of sebaceous gland: PGI June 2007Propionic bacterium acnesDiphtheriaStreptopyogensStaph aureus  <response>: Ans. A Propionic bacterium acnes Propiniobacterium acnesQ a normal commensalQof 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 3rd9SFig- Etiology- of Acne vulgarisAnaerobic 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 