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

Xiaoyi Liu,1,* Zhiwei Lin,2,* Yiwen Li,3 Zhiwei Zhong,1 Aiwu Wu,1 Yueting Jiang3 1KingMed School of Laboratory Medicine, Guangzhou Medical University, Guangzhou, People’s Republic of China; 2Department of Clinical Laboratory of the First Affiliated Hospital of Guangzhou Medical University, State Key Laboratory of Respiratory Disease, National Center for Respiratory Medicine, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, Guangzhou, People’s Republic of China; 3Department of Clinical Laboratory, the Key Laboratory of Advanced Interdisciplinary Studies Center, the First Affiliated Hospital of Guangzhou Medical University, National Center for Respiratory Medicine, Guangzhou, People’s Republic of China*These authors contributed equally to this workCorrespondence: Aiwu Wu; Yueting Jiang, Email [email protected]; [email protected]: 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 Mycobacteroides abscessus isolated from clinical departments with broth microdilution method, and rrl, rrs and erm (41) 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 (χ2 = 10.688, P = 0.014). M. abscessus (61, 42.36%), M. intracellulare (35, 24.31%) were the two most NTMs in this hospital. Clinical strains of M. abscessus exhibited high resistance to antibiotics, except for cefoxitin (31.8%), linezolid (25.0%), amikacin (0%), and clarithromycin (18.2%). Among 8 strains of M. abscessus with clarithromycin acquired resistance, just 4 strains (50.0%) showed mutations (A2270G, A2271G) in rrl gene, but a new mutation (C2750T) was detected in 1 strain. Among 14 strains of M. abscessus with clarithromycin-induced resistance, 13 (93.0%) strains had T28 erm (41) gene and 1 (7.0%) strain had C28 erm (41) gene.Conclusion: M. avium–intracellulare complex was gradually becoming predominant strain in Guangzhou area. The resistant situation of M. abscessus in general hospital had shown severe. Potential mutation in rrl gene associated with clarithromycin acquired resistance of M. abscessus were found, but drug-resistant mechanism remained unclear.Keywords: nontuberculous mycobacterium, drug resistance, clarithromycin, Mycobacteroides abscessus