Analysis of Clinical Isolation Characteristics of Nontuberculous Mycobacteria and Drug Sensitivity of Rapidly Growing Mycobacteria in the General Hospital of Guangzhou, China.

Purpose: The clinical distribution characteristics of nontuberculous mycobacteria (NTM) in general hospital were explored to guide the clinical diagnosis and treatment of NTM infection.

Methods: Samples with positive mycobacterium culture in the First Affiliated Hospital of Guangzhou Medical University were collected and identified through PCR. Phenotypic drug sensitivity experiments were conducted on 44 isolated from clinical departments with broth microdilution method, and and genes associated with drug resistance were detected.

Results: From September 2020 to July 2023, 314 mycobacterium-positive isolates were separated from patients in the First Affiliated Hospital of Guangzhou Medical University, with 147 (46.8%) NTM isolates were included in our study. The samples were respiratory tract specimens mainly, with 64% bronchoalveolar lavage fluid. Of 144 cases identified, samples were from 133 patients (60 males and 73 females; gender ratio of 0.82:1). NTM was mainly isolated from the people aged 40 and above, especially females ( = 10.688, = 0.014). (61, 42.36%), (35, 24.31%) were the two most NTMs in this hospital. Clinical strains of exhibited high resistance to antibiotics, except for cefoxitin (31.8%), linezolid (25.0%), amikacin (0%), and clarithromycin (18.2%). Among 8 strains of with clarithromycin acquired resistance, just 4 strains (50.0%) showed mutations (A2270G, A2271G) in gene, but a new mutation (C2750T) was detected in 1 strain. Among 14 strains of with clarithromycin-induced resistance, 13 (93.0%) strains had T28 gene and 1 (7.0%) strain had C28 gene.

Conclusion: complex was gradually becoming predominant strain in Guangzhou area. The resistant situation of in general hospital had shown severe. Potential mutation in gene associated with clarithromycin acquired resistance of were found, but drug-resistant mechanism remained unclear.