A50-12 Kennel Cough: Not Limited to Pets? An Unusual Bug Causing Severe Septic Shock

Neutropenic fever is a well-recognized infectious entity, with a significant percentage having no identifiable causative micro-organism. Sepsis due to neutropenic fever presents a unique challenge: rarity of causative organisms, inadequate history, and profound immunosuppression. In this case, we discuss bacterial pneumonia causing septic shock due to a rare micro-organism. A 63-year-old woman with Stage III multiple myeloma presented six days after an autologous stem cell transplant. At presentation, she was found to be febrile (39.4 degrees C) and tachypneic (respiratory rate of 35-42 breaths/minute) and was admitted for neutropenic fever. The patient endorsed diarrhea and severe shortness of breath. Labs at admission demonstrated pancytopenia (hemoglobin of 7.7 g/dL, white blood cell count of 0.03 K/uL and platelets 9K/uL) with mild lactic acidosis (2.7 mmol/L). The patient was moved to the intensive care unit shortly after due to acute hypotension and increased work of breathing. Her arterial blood gases demonstrated severe acidosis and acute hypercarbia (pH 6.97 and pCO2 60), warranting intubation and vasopressor support. Empiric antibiotic coverage was broadened to meropenem, vancomycin and micafungin. Computed tomography (CT) with contrast of her chest revealed multilobar pneumonia versus aspiration. Blood cultures were negative, as was a respiratory viral panel. On Day 4 of intubation, gram stain of sputum culture showed gram negative rods. The patient’s clinical course was complicated by coughing episodes resulting in increased vagal tone with bradycardia, ventilator desynchrony and hypotension. To minimize these episodes, the patient was paralyzed and heavily sedated. The patient was treated with tobramycin to double cover for possible resistant Pseudomonas and a macrolide was initiated for possible atypical organisms. Ultimately, sputum cultures were speciated to be Bordetella bronchiseptica, a close relative of Bordetella pertussis which causes human whooping cough. The patient continued treatment with broad spectrum antibiotics and was weaned off sedation and paralysis with decreasing ventilator requirements around day 9 but did ultimately require tracheostomy for prolonged respiratory failure. Bordetella bronchiseptica is a common causative organism of upper respiratory tract infections in non-human mammals but there is sparse data to suggest it causes human infection. The few studies that explore its role as a causative organism reach the conclusion that hosts must be severely immunocompromised for it to be virulent. Given its rarity, antibiotic susceptibility data is limited. However, unlike Bordetella pertussis, it appears resistant to macrolide antibiotics. This case highlights the importance of considering rare commensals as causative organisms in neutropenic fever. This abstract is funded by: None