Objective: Non-tuberculous mycobacteria (NTM) are common in the environment and they are isolated as an etiological agent, especially in immunocompromised patients. Due to their frequent resistance to classical anti-tuberculosis drugs and their increasing frequency of isolation, accurate and early diagnosis of NTM infections is very important in terms of treatment success. The aim of this study was to evaluate retrospectively the results obtained from the samples of NTM diagnosed in the Mycobacteriology Laboratory of Dokuz Eylül University Hospital between 2012- 2016 and changes over the years were analyzed.

Material and Methods: The samples sent to mycobacteriology laboratory were studied with Löwenstein-Jensen culture media, and BACTEC MGIT 960 systems. In case of clinical request, identification of NTM isolates at species level was performed by using a commercial line-probe assay (GenoType Mycobacterium CM; Hain Lifescience, Germany). If the same NTM species was isolated more than once in the clinical specimen of a patient, then it was considered as a causative agent.

Results: Out of 11804 clinical specimens sent to the laboratory with the initial diagnosis of tuberculosis in the period 2012 and 2016, NTM were identified in 299 samples. Species identification by GenoType Mycobacterium CM was performed on 66 of the NTM strains. The most frequently identified NTM species was Mycobacterium fortuitum (n=41), followed by Mycobacterium abscessus (n=11), Mycobacterium chelonae (n=6), Mycobacterium gordonae (n=5), Mycobacterium intracellulare (n=2) and Mycobacterium kansasii (n=1). Conclusion: Respiratory tract specimens were the most common specimens when NTM isolated samples were evaluated according to sampling sites. As a striking feature, rapidly growing NTM species were the most frequent species isolated in our laboratory.