Nontuberculous mycobacteria in respiratory tract samples: what does-it mean?

<b>Background:</b> The prevalence of nontuberculous mycobacteria (NTM) infection is increasing worldwide, particularly the respiratory ones. The improvement of microbiological detection methods has allowed a more precise identification of the NTM. At present, very little research exists in Tunisia. <b>Aim:</b> -&nbsp;Describe clinical and radiologic findings associated with NTM pulmonary disease (NTM-PD) in immunocompetent patients. -&nbsp;Set out the profile of NTM species in our hospital. <b>Methods:</b> Multicentric study including immunocompetent patients with respiratory NTM isolation for the past ten years (2010-2020) in the Mami Ariana Hospital. <b>Results:</b> Thirty-eight patients were enrolled (male: 68,4%; mean age: 56 years). Past medical history included pulmonary tuberculosis (PTB) (57%), chronic obstructive pulmonary disease (15%), bronchiectasis (15%) and multidrug-resistant TB (10%). Main symptoms were cough (55%), weight loss (52%), dyspnea (36%), fever (34.2%) and hemoptysis (18%). Chest X-ray screening showed pulmonary infiltrates (35%), lung nodules (45%) and cavitary lesions (37%). Eleven species were identified. The most prevalent ones were <i>M. avium</i>&nbsp;complex (23%), <i>M. fortuitum</i> (31%) and <i>M. kansasii</i> (21%). The isolates were from sputum specimens (92%) and bronchial aspirate (7%). Eleven patients fulfilled the ATS/IDSA criteria for NTM-PD. Eight patients were treated. Three patients were classified as colonized patients. Nine positive NTM cultures were due to environmental contamination. The final diagnoses remained unclear for 15 patients. <b>Conclusion:</b> NTM in respiratory samplings doesn’t mean infection. PTB infection seems to be the major risk factor. <i>M. avium</i>&nbsp;complex was the most prevalent species in our study.