We describe a case of
thoracic empyema in a 76-year-old male with complication of
diabetes mellitus and
hypertension. His chief complaints were
fever and
chest pain. The patient was diagnosed as pleural
infection according to the pulmonary computed tomography (CT) scan and laboratory results. The patient had persistent
fever after the treatment of continuous percutaneous drainage and 1 week of intravenous
moxifloxacin. He was then misdiagnosed as tuberculous
pleuritis and still had
fever after the treatment of 2 weeks' antituberculosis drugs. Repeated cultures of sputum, blood, bronchoalveolar lavage fluid and pleural fluid were all negative. A gram-negative bacillus was found in the pleural
pus Gram
stain, and it was identified as Prevotella spp. by 16S
ribosomal DNA (
rDNA) sequence analysis. The patient recovered after further treatment, including CT-induced pleural drain and intravenous
imipenem. Totally, he received 2-week
imipenem and 1-month
metronidazole therapy from the day he was diagnosed with
empyema to the termination of treatment. On the subsequent 2-month and 6-month follow-up visits, no recurrence has been reported for this patient. Routine microbiological methods are important in diagnosis of pleural
infection, but they have limitations in some cases, especially for anaerobe. Molecular assay based on 16S
rDNA is helpful in detecting causative organisms of
thoracic empyema.