Mycobacterium florentinum pulmonary disease: A case report and review of the literature

Background: Following the initial description of Mycobacterium florentinum in 2005, very few clinical cases have been reported and the optimal antimicrobial treatment and clinical outcomes are uncertain. Amikacin liposomal inhalation suspension (ALIS) has received approval for the treatment of Mycobacterium avium/intracellulare complex (MAC) pulmonary disease. However, there is little experience with its use for infections caused by less common nontuberculous mycobacteria (NTM). Moreover, the awareness of uncommon adverse effects is still limited. Case presentation: A 69-year-old female patient suffering from nodular bronchiectatic Mycobacterium florentinum pulmonary disease was treated with azithromycin, ethambutol, and rifampicin, administered three times per week. After 13 months, owing to treatment failure, the therapy was changed to ALIS, moxifloxacin, and clofazimine. This resulted in rapid and sustained culture conversion. Concurrently, the patient exhibited increased cough and sputum, which was consistent with a clinical diagnosis of aspergillosis, as confirmed by evidence of Aspergillus fumigatus in respiratory specimens and a significant increase in serum anti-Aspergillus IgG antibody levels. Following a six-month course of antifungal therapy, a marked improvement in the patient's symptoms was observed. Conclusions: As with MAC pulmonary disease, combination antimicrobial therapy including ALIS was successful in a patient affected by a difficult-to-treat pulmonary infection caused by Mycobacterium florentinum , a rare NTM pathogen. Combination antibiotic treatment including ALIS may also be considered for difficult-to-treat non-MAC NTM- pulmonary diseases, when based on the results of in-vitro drug-susceptibility testing.