[Pulmonary infection with Mycobacterium malmoense. Difficulties in diagnosis and treatment]

Pulmonary infection due to Mycobacterium malmoense can be difficult to diagnose. These difficulties can be responsible for a delay in the implementation of optimal treatment. Moreover, the treatment is not standardized.

We report the case of a 56-year-old patient who developed a Mycobacterium malmoense pulmonary infection whose diagnosis was delayed due to initial suspicion of pulmonary Mycobacterium tuberculosis infection. Once the diagnosis was confirmed, the patient was treated empirically with rifampicin, ethambutol, and clarithromycin for 12 months after culture conversion, giving a total of 15 months. The clinical and radiological outcomes were favorable.

This clinical case highlights the difficulties of diagnosing pulmonary atypical mycobacterial infection according to the American Thoracic Society criteria, particularly Mycobacterium malmoense, a non-tuberculous mycobacterium (NTM) quite uncommon in France. Currently, there are new diagnostic techniques such as GenoType Mycobacteria Direct^®. The second issue is the poorly standardized treatment of this NTM and many others, that are based on the recommendations of the British Thoracic Society. A national register has been set up by the MycoMed network, based essentially on the work of microbiologists but this register is unfortunately not exhaustive.

A more systematic reporting strategy could allow cohort studies and therefore provide us with data on the most efficient drugs in the treatment of the rarest NTM infections.