Chronic granulomatous pleuritis caused by nocardia: PCR based diagnosis by nocardial 16S rDNA in pathological specimens.

Nocardiosis is an uncommon infection caused by the aerobic actinomycete nocardia. Identification of the pathogen is essential for the definitive diagnosis and for an effective treatment. This report describes a case of chronic granulomatous pleuritis caused by nocardia. A 59 year old Japanese man had a history of repeated pyothorax. Right pleural decortication and thoracic drainage were performed. Microbiological examinations of the drained fluid failed to identify a pathogen. Pathological examinations revealed Gram positive filamentous and branching bacilli in the granulomatous lesion of the pleura. Sequencing of the 971 bp 16S ribosomal DNA extracted and amplified from paraffin wax embedded sections identified the microorganism as Nocardia sp. IFM 0860. The patient received sulfamethoxazol/trimethoprim and minocycline. Although the presence of a brain abscess was disclosed by systemic examination, the clinical course has been favourable. In this patient, polymerase chain reaction analysis of 16S ribosomal DNA in pathological specimens was useful in making an accurate diagnosis of nocardiosis and in determining the appropriate treatment.