B73-40 Lung Abscess Due to Streptococcus Anginosus Group Infection Progressing to Life-Threatening Empyema: A Challenge of Early Recognition and Source Control

Abstract Introduction Streptococcus Anginosus Group (SAG) of bacteria are a facultative anaerobe that form part of the oral flora but are known for a high potential to cause invasive pyogenic infections. Despite their highly virulent nature they are not always isolated on sputum or blood cultures. We present a case of SAG associated empyema in a 49-year-old male with SAG empyema diagnosed on biopsy. Case presentation 49-year-old male with a past medical history of hypertension who presented with a 6-week history of cough and exertional dyspnea associated with fever, chills and night sweats. He had been seen as an outpatient for these symptoms and had a CT chest done which revealed a right upper lobe lung nodule with surrounding ground-glass infiltrate (Figure A). On admission, labs showed WBC of 19.78 with left shift. Blood and sputum cultures were negative. The nodule was biopsied and found to contain pus. He was started empirically on ampicillin/sulbactam for lung abscess but decompensated over the following 2 days requiring admission to the ICU and intubation with escalation of antibiotics to ceftriaxone and metronidazole. Cultures from his lung biopsy grew positive for SAG. Repeat imaging revealed a large loculated pleural effusion (Figure B) and a pigtail chest tube was placed and subsequently instilled with alteplase/dornase. He was successfully extubated after 5 days in the ICU with improvement in his respiratory status. Despite his respiratory improvement, his empyema persisted (Figure C) even after repeat instillation of alteplase/Dornase and so VATS was considered. Patient however requested discharge against medical advice and was given a 6-week course of Amoxicillin/clavulanic acid with plans for outpatient CT (Figure D). Discussion SAG is normal flora found in the oral cavity and upper respiratory tract. It is known to be pathogenic with a potential to be highly invasive and pyogenic. Despite being implicated in severe infections, they rarely cause bacteremia and are difficult to isolate on conventional sputum and pleural fluid culture data. When isolated they are implicated in both pure and polymicrobial infections. As with our patient, tissue biopsy may be required for SAG isolation, though the relative invasiveness of this modality limits its utility in diagnosis. We therefore recommend that SAG remain on the differential for progressive and invasive lung infections and rapidly growing empyemas even when culture data is negative. Early drainage and decortication must be considered for source control to help mitigate the high mortality associated with this condition. This abstract is funded by: None