B73-39 Dual Threat: Polymicrobial Empyema and Diaphragmatic Abscess Due to Candida Krusei and Fusobacterium Nucleatum

Abstract Introduction Empyema and diaphragmatic abscess are life-threatening sequelae of severe pneumonia or aspiration, typically caused by bacterial pathogens. Fungal empyema is rare, and concurrent fungal-anaerobic infection is exceptionally uncommon. Candida krusei is an intrinsically fluconazole-resistant yeast seldom isolated from the pleural space, and its coexistence with Fusobacterium nucleatum—an anaerobe linked to aspiration and necrotic pneumonia—has been reported only rarely. We describe a case of mixed bacterial and fungal empyema with diaphragmatic abscess, emphasizing diagnostic vigilance and multidisciplinary management. Case Presentation An 83-year-old man with dementia, hypertension, type 2 diabetes, and a chronic sacral ulcer presented with progressive dyspnea and decreased responsiveness. He had been bedbound for several months with poor oral intake and frequent aspiration episodes. On arrival, he was hypotensive, tachycardic, tachypneic, and hypoxemic. Laboratory evaluation revealed hypernatremia, anion-gap metabolic acidosis, and lactic acidosis. Chest radiograph showed bilateral airspace consolidation and pleural effusions. He was started on broad-spectrum antibiotics (vancomycin and piperacillin-tazobactam) for presumed pneumonia but developed septic shock requiring intubation and vasopressors. Repeat imaging demonstrated extensive bilateral consolidation, a moderate-to-large complex right hydropneumothorax concerning for empyema, and a small rim-enhancing fluid collection along the right hemidiaphragm consistent with abscess formation. Because of a bronchopleural fistula and high procedural risk, operative intervention was deferred, and Interventional Radiology performed image-guided chest-tube drainage. The purulent fluid grew Candida krusei and Fusobacterium nucleatum; endotracheal aspirate cultures yielded MSSA, Klebsiella aerogenes, Stenotrophomonas maltophilia, and Enterobacter cloacae complex. Antimicrobial therapy was broadened to meropenem, trimethoprim-sulfamethoxazole, and micafungin after Infectious Disease consultation. Following stabilization, tracheostomy and PEG tube were placed, and the patient was discharged to a long-term acute-care facility on a prolonged antibiotic course. Discussion Mixed fungal-anaerobic empyema represents an exceptionally rare entity. The coexistence of Candida krusei and Fusobacterium nucleatum underscores the polymicrobial nature of aspiration-related infections in chronically debilitated hosts. Their isolation highlights the importance of comprehensive microbiologic evaluation, including fungal cultures, in persistent or atypical pleural infections. This case reinforces key management principles: early, aggressive source control; prompt broad-spectrum and antifungal therapy refined by culture data; and close interdisciplinary collaboration among pulmonary, infectious-disease, and interventional teams. Recognizing such uncommon co-infections is critical to guide appropriate antifungal selection—particularly given C. krusei’s intrinsic fluconazole resistance—and to ensure timely, targeted therapy in high-risk patients. This abstract is funded by: None