Nontuberculosis Mycobacterial Infections: A Series of 14 Cases from a Tertiary Care Center in Türkiye

Nontuberculous mycobacteria (NTM) are emerging opportunistic pathogens with an increasing global incidence. However, epidemiological data and treatment outcomes remain limited in Türkiye. This study aimed to evaluate the clinical characteristics, species distribution, and treatment outcomes of NTM infections in a tertiary center in Türkiye.

A retrospective analysis was conducted of patients diagnosed with NTM infection between 2021 and 2025 in the Department of Infectious Diseases and Clinical Microbiology. The diagnosis was established according to the American Thoracic Society/Infectious Diseases Society of America (ATS/IDSA) criteria. Demographic characteristics, risk factors, radiological findings, microbiological profiles, antimicrobial susceptibility patterns, treatment regimens, and clinical outcomes were analyzed.

Fourteen patients were included in the study. The mean age was 50.1 ± 13.8 years, and nine patients were male. Underlying risk factors were present in eight patients, including human immunodeficiency virus (HIV) infection (n = 4), malignancy (n = 3), bronchiectasis (n = 1), and chronic obstructive pulmonary disease (COPD) (n = 1). The most frequently identified species were Mycobacterium kansasii (n = 5) and Mycobacterium abscessus (n = 5), followed by Mycobacterium avium, Mycobacterium simiae, Mycobacterium gordonae, and Mycobacterium lentiflavum (n = 1 each). Pulmonary involvement was observed in 10 patients, with nodular lesions in nine and bronchiectasis in five. Among isolates with available antimicrobial susceptibility results (n = 13), susceptibility to clarithromycin, moxifloxacin, linezolid, and amikacin was observed in 12 isolates, whereas resistance was most frequently detected to ciprofloxacin (n = 10) and trimethoprim-sulfamethoxazole (n = 9). Of the 12 patients who initiated treatment, complete clinical response was achieved in nine and partial response in one; two patients with malignancy died before treatment initiation.

M. kansasii and M. abscessus were the most frequently identified NTM species in this cohort. Favorable treatment outcomes were observed when therapy was guided by antimicrobial susceptibility results. Species-level identification and susceptibility testing are essential for optimal disease management and strengthening diagnostic capacity.