Bronchopneumonia caused by Propionibacterium acnes.

Propionibacterium acnes was identified as the pathogen in a case of subacute lung infection by examination of an open lung biopsy specimen. The patient was a 65-year-old male with exacerbation of chronic lung disease. The organism was isolated in pure culture and was present in large numbers on Gram stain. Histological examination demonstrated active interstitial fibrosis; macrophages laden with Propionibacterium acnes antigen were revealed using a peroxidase-antiperoxidase stain. This is the first report of subacute infection of pulmonary tissue due to this organism.