Propionibacterium acnes: an uncommon cause of lung abscess in chronic obstructive pulmonary disease complicated with bullous emphysema

A 57-year-old man who had recurrent respiratory infections due to tobacco use and severe chronic obstructive pulmonary disease (COPD) was evaluated as an outpatient to discern the etiology. He was followed with a chest X-ray and a chest computed tomography (CT) scan that displayed a left upper lobe cavitary lung abnormality. The lesion was further evaluated with a CT-guided biopsy, and it was identified as a lung abscess. A tissue culture isolated Propionibacterium acnes. We present a rare case of a common skin commensal, P. acnes, that infected the left upper lobe of the lung. We presume that the patient was predisposed to infection secondary to degradation of pulmonary parenchyma by severe bullous emphysema. This destruction created an inflammatory and colonizing space for organisms, even uncommon forms, to flourish. Initially this presentation prompted a differential of pulmonary tuberculosis; however, with further workup, the diagnosis was excluded. This case highlights the potential of P. acnes, an uncommon lung microbe, to lead to a lung abscess in a patient who was otherwise immunocompetent. This case will allow osteopathic clinicians to detect an uncommon microorganism that can potentially cause a pulmonary abscess in a patient with a medical history of severe bullous emphysematous COPD.