A50-45 Beyond the Usual Suspects: Pasteurella-induced Empyema in an Immunocompetent Host

Abstract Introduction Pasteurella multocida, a gram-negative bacterium in the oral flora of cats and dogs, is a rare cause of lower respiratory infections and empyema, mainly affecting those with lung disease, immunosuppression, or animal exposure. However, severe cases needing ICU care can occur in healthy individuals without known exposure. We present a case complicated by septic shock and respiratory failure requiring mechanical ventilation. Description A 62-year-old woman with diabetes and hypertension presented with a two-week history of worsening shortness of breath, fever, and productive cough. Labs showed lactic acidosis, elevated ketones, and positive influenza A PCR. Imaging revealed multifocal pneumonia and a large left pleural effusion without pulmonary embolism. Initially supported with high-flow nasal oxygen (AIRVO), her breathing worsened, requiring BiPAP and then intubation with mechanical ventilation. She developed septic shock needing vasopressors and was treated empirically with vancomycin, piperacillin-tazobactam, azithromycin, and oseltamivir. Chest tube and central line were placed. Cultures grew Pasteurella multocida, leading to antibiotic de-escalation to ceftriaxone. ICU complications included ventilator dyssynchrony managed with ketamine, acute kidney injury, new atrial fibrillation with rapid ventricular response, reduced ejection fraction, and pressure ulcers. After stabilization, vasopressors were stopped and she was extubated. Persistent encephalopathy and swallowing difficulties required PEG placement, and due to poor recovery, family chose hospice care. Discussion Pasteurella multocida respiratory infections, though uncommon, can cause severe pneumonia and empyema, especially in older adults with metabolic or heart conditions. This case emphasizes considering zoonotic pathogens in complex pneumonia, even without animal exposure. Timely thoracentesis and culture are key for diagnosis. Treatment includes beta-lactam antibiotics and pleural drainage when needed. Patients may rapidly worsen, requiring ventilation and intensive care due to complications like arrhythmias and kidney injury. Early diagnosis and targeted therapy are vital for better outcomes. AI editing tool was used for this abstract. This abstract is funded by: None