Cavitary lung lesions – microbiological identification of mycobacteriosis

<b>Introduction:</b> A significant increase in the incidence of mycobacteriosis is due to the improved diagnostic methods and increased proportion of immunosuppressed patients. <b>Aim:</b> To analyze microbiological profile of non-tuberculosis mycobacteriosis (NTMB) in patients with cavitary lung lesions. <b>Materials and Methods:</b> We examined 102 patients with newly detected lung cavities. Of them, 75.4 % were men and 24.6 % - women between 18 and 80 years of age. Microbiological examination of the diagnostic material (sputum, BB/TBBL, surgical lung cavity resection material), liquid culture in ВАСТЕС MGIT, real-time PCR for identification of MTB DNA and DNA strips tests were performed. <b>Results:</b> In 23/102 (23.5%) patients with lung cavities, presence of Mtb in the diagnostic material was not detected by any of the used microbiological methods. MTB were identified in 39/102 (38.2%) patients. Based on the BTS (2017) criteria, 40/102 (39.2%) pts. were diagnosed with NTMB: M. avium complex – 35%, M. kansasii-27.5%, M. intracellulare-12.5%, M. xenopi-10%, M. abscessus-5%, M. gordonae, M. fortuitum, M. maimoense and M. szulgas-2.5% each. In 18/40 (45%) pts., NTMB were isolated from sputum, in 12/40 (30%) pts. from BB/TBBL, and in 10/40 (25%) pts. from the surgical biopsy material obtained from lung cavities. <b>Conclusions:</b> Microscopy is not a reliable method for differential diagnosis between Mtb and NTMB infections.To avoid errors in diagnosis, species identification of mycobacteria is required. For NTMB infection with lung cavities, the most typical is the predominance of slow-growing NTMB species, with the majority of M. avium-35% and M. kansasii-27.5%.