Case Presentation: A 54 year-old man with a history of opioid use disorder, housing insecurity and hypoplastic myelodysplastic syndrome presented with one month of shortness of breath, productive cough, fever, and chills. He also endorsed a twenty pound weight loss over the course of three months. He had presented to an outside hospital three weeks prior for similar symptoms, diagnosed with pneumonia, and treated with a course of levofloxacin and prednisone. He took the entire course but did not notice any improvement in his symptoms. He denied night sweats, recent travel and any known sick contacts. He was tachycardic to 110 beats per minute with increased work of breathing and required 3 liters of supplemental oxygen to maintain saturations greater than 90%. Coarse breath sounds were noted diffusely on pulmonary auscultation. His heart rhythm was normal and no murmurs were appreciated. No consolidations or pulmonary edema noted on chest x-ray. A CT scan of his chest demonstrated a right perihilar soft tissue mass compressing the bronchus intermedius and encasing the right pulmonary artery, initially concerning for bronchogenic carcinoma. Pulmonology was consulted and a bronchoscopy was performed. Bronchial alveolar lavage cultures were positive for Mycobacterium abscessus. Fine needle aspirations from the right perihilar mass and surrounding lymph nodes were negative for malignancy, positive for neutrophils, lymphocytes, and necrotic debris. The patient also had two blood cultures on admission that grew Mycobacterium abscessus on hospital day seven. The patient was started on Amikacin, Imipenem, Eravacycline and Tedizolid and remains admitted for a planned six-twelve month course of IV antibiotics.

Discussion: Mycobacterium abscessus is a type of nontuberculous mycobacteria that usually presents as an opportunistic infection in susceptible hosts. In the United States, M. abscessus infections have an annual prevalence of < 1 per 100,000, however the prevalence has been increasing over the past few decades. M. abscessus has been known to cause pulmonary disease, skin and soft tissue infections, central nervous system infections, and bacteremia. It is notoriously resistant to standard antituberculosis agents and most antimicrobial agents. Cure rates are low, with success seen in only 30-50% of patients. Treatment courses have an average length of 18 months and require multiple agents. There is limited data on preferred regimens at this time, though macrolides are the mainstay of therapy.

Conclusions: Though rare, Mycobacterium abscessus infections pose an incredibly difficult treatment challenge for hospitalists due to the multidrug resistance and the fast growing nature of the mycobacterium. Early diagnosis of this pathogen is critical to prevent progression and it should routinely be considered as a potential cause of opportunistic infections in vulnerable hosts.