Bilateral parapneumonic empyema caused by Fusobacterium necrophorum infection in a healthy individual

Pulmonary infection caused by Fusobacterium necrophorum, an obligate anaerobic gram-negative bacterium, most commonly occurs as a part of Lemierre's syndrome, i.e., pharyngotonsillitis complicated by septic thrombophlebitis of the internal jugular vein and secondary lung abscesses. A 51-year-old previously healthy man was admitted to our hospital with pleuritic right-sided chest pain. No sore throat, dysphagia, or neck pain was observed. Chest radiography and computed tomography (CT) revealed massive right pleural effusion and bilateral bronchopneumonia. Right thoracic drainage yielded purulent fluids, from which a pure culture of F. necrophorum was isolated. Blood culture and broad-range polymerase chain reaction for bacterial 16S ribosomal ribonucleic acid on blood samples were negative. CT scan showed no evidence of internal jugular vein thrombosis or peritonsillar abscess. The right thoracic tube was removed after the purulent fluids were no longer drained. Although the antibiotic treatment was continued with intravenous sulbactam/ampicillin, to which F. necrophorum was sensitive, left purulent pleural effusion emerged. The antibiotic was switched to clindamycin, cefazolin, cefotiam, and flomoxef. Although the left pleural effusion gradually decreased, the right purulent pleural fluid was reaccumulated. Thus, the patient underwent right-sided thoracoscopic decortication and debridement, followed by thoracic lavage through a chest tube with saline solution. After the surgery, the patient's condition improved, and no recurrence of pleural effusion was observed. This report presents the case of a previously healthy patient with bilateral parapneumonic empyema caused by F. necrophorum, without manifestations of pharyngotonsillitis, bacteremia, or Lemierre's syndrome. Extensive thoracic drainage, effective antibiotics, and timely surgical interventions are imperative.