Fig. 2From: Actinomycosis presenting as an isolated pleural effusion in a patient with an HIV infection: a case report and literature reviewA Histologic examination: hematoxylin and eosin (H & E) staining (× 400). A bacterial colony (sulfur granule) is found at the center of mixed inflammatory cells. B Grocott methenamine silver stain (GMS) stain (× 1000). The GMS stain demonstrates filamentous bacteriaBack to article page