Abstract Introduction Mycobacterium cosmeticum is a nontuberculous Mycobacterium (NTM) most commonly associated with skin and soft tissue infections. Documented instances of lung infection by this microorganism are rare. We present a patient with chronic granulomatous lung disease and bronchiectasis who developed sequential pulmonary NTM infections involving M. cosmeticum, M. chimaera, and M. intracellulare. Case A 66-year-old retired shipyard worker with a history of hypertension and hyperlipidemia presented to the pulmonology clinic and subsequently to the infectious disease clinic with a chronic productive cough. Chest imaging showed bronchiectasis in the right middle lobe and lingula, as well as a granuloma in the left upper lobe with bilateral calcified perihilar and mediastinal lymph nodes. Two sputum cultures six months apart were positive for acid-fast bacilli (AFB) and grew Mycobacterium cosmeticum. The patient was diagnosed with NTM pulmonary disease based on imaging findings, clinical symptoms, and positive sputum cultures growing Mycobacterium cosmeticum, a rapidly growing NTM species. Given mild, noncavitary nodular-bronchiectatic disease and prior literature demonstrating response to macrolide-based regimens, he was started on azithromycin, rifampin, and ethambutol. After extended incubation, Mycobacterium cosmeticum demonstrated inducible macrolide resistance, becoming clarithromycin-resistant despite initial susceptibility. It remained susceptible to all other tested agents, including amikacin, cefoxitin, fluoroquinolones, doxycycline, imipenem, linezolid, and trimethoprim-sulfamethoxazole. Follow-up sputum cultures obtained approximately one year later grew Mycobacterium chimaera and Mycobacterium intracellulare, both of which were susceptible to his current regimen. He subsequently underwent bronchoscopy with bacterial, fungal, and AFB cultures and biopsy of the left upper lobe granuloma, all of which were negative. He continues to report symptomatic improvement on follow-up. Discussion Mycobacterium cosmeticum is typically linked to cutaneous infections following cosmetic procedures. It is a novel pulmonary pathogen. Its persistence on repeated sputum cultures, along with the patient’s symptoms and compatible imaging findings, indicated actual infection rather than colonization. This case highlights the therapeutic challenges posed by rare NTM lung infections. The inducible macrolide resistance observed in Mycobacterium cosmeticum underscores the importance of obtaining susceptibility testing to guide therapy in rare NTM species. Although macrolide resistance was identified, therapy was continued given the patient’s clinical improvement, culture clearance and limited sensitivities. The patient remains on macrolide-based therapy and is planned to continue treatment for 12 months following his last negative cultures. He has improved clinically despite minimal susceptibility data, suggesting that empiric macrolide-based therapy can be effective in this setting. This abstract is funded by: None
Sheikh et al. (Fri,) studied this question.