A102-11 Endobronchial Antibiotic Instillation for Refractory Lung Abscess Due to Streptococcus Pyogenes

Abstract Introduction Lung abscess treatment is challenging and fails in 10-20% of cases. Intracavitary antimicrobial instillation is described to treat aspergillomas, but data for bacterial lung abscesses is limited. We present a case of Streptococcus pyogenes (S. pyogenes) pneumonia with a pulmonary abscess treated with endobronchial antibiotics. Case Report A 35-year-old male with rheumatoid arthritis presented with fever and cough, and was found to have influenza A and S. pyogenes bacteremia. He was initially treated with oseltamivir, ceftriaxone, and azithromycin. On hospital day 5 he developed a right tension pneumothorax requiring tube thoracostomy, mechanical ventilation, and ultimately veno-venous extracorporeal membrane oxygenation (ECMO) for acute respiratory distress syndrome (ARDS). Despite broadening antimicrobials chest computed tomography (CT) on hospital day 13 demonstrated worsening consolidation with right upper lobe (RUL) abscess progression (Fig. 1A-B). Given concern for poor abscess penetration after two weeks of treatment, we considered endobronchial antibiotic instillation near the abscess in addition to IV antibiotics. On hospital days 15-18, 600mg clindamycin was instilled daily into the RUL segmental airways: An endobronchial blocker was placed into the target airway, and clindamycin was delivered in three 60mL aliquots, monitoring for leakage. The blocker remained inflated for 15 minutes. On hospital day 16, antibiotics were narrowed to penicillin G. The patient’s lung compliance began to improve, paralytics were discontinued on day 23, and a repeat chest CT on day 24 demonstrated abscess and lung aeration improvement (Fig. 1C). On hospital day 39 he was decannulated from ECMO, and on day 46 discharged on oral amoxicillin. CT prior to discharge showed continued improvement (Fig. 1D). Discussion Endobronchial antibiotic instillation is described, but only for bronchoscopically accessible abscess cavities. In our patient, the abscess was multi-focal without apparent airway communication, so clindamycin was instilled near, not in, the abscess. With a multi-disciplinary team of experts including critical care, interventional pulmonology, radiology, infectious disease, and pharmacy, we established a protocol and antibiotic choice considering several aspects, including efficacy against S. pyogenes, concentration-dependent kinetics, and lavage of appropriate volume. The antibiotic and aspirated fluid pH were tested before and after dwell (7.2 and 7.4, respectively). Though definitive causative inferences about clinical improvement cannot be made, our protocol appeared safe, well-tolerated, and temporally associated with recovery. Proximate endobronchial antimicrobial instillation may have utility in treating refractory pulmonary abscesses, with careful consideration to rationale, patient selection, and antimicrobial choice. This abstract is funded by: None