September 17, 2025Open Access

Age- and Gender-Specific Distribution and Susceptibility-Guided Multidrug Strategies in NTM Lung Disease: A retrospective study from a specialized hospital in China

Key Points

Gender disparities in NTM-PD prevalence show a male predominance with increasing age and significant incidence.
Evaluation of 606 NTM isolates identified 21 species, with Mycobacterium avium complex constituting the majority.
Susceptibility testing reveals that clarithromycin, linezolid, and amikacin are most effective against NTM, while imipenem shows limited activity.
Species-specific multidrug treatment strategies are essential, informed by local epidemiological antimicrobial susceptibility patterns.

Abstract

Introduction: Nontuberculous mycobacteria (NTM) are causative pathogens of NTM pulmonary disease (NTM-PD), which is managed with multidrug regimens guided by antimicrobial susceptibility testing (AST). This study evaluated the AST profiles of clinical NTM isolates from a specialized hospital and proposes targeted therapeutic strategies for NTM-PD. Methodology: Diagnosis of 606 NTM-PD cases complied with American Thoracic Society (ATS) criteria. Broth microdilution methodology quantified minimum inhibitory concentrations (MICs) for antimicrobial agents against NTM isolates obtained from sputum or bronchoalveolar lavage specimens. Susceptibility profiles among NTM species were systematically evaluated to establish optimized treatment regimens using pharmacodynamically validated breakpoint parameters. Results: Epidemiological analysis revealed a statistically significant gender disparity in NTM-PD prevalence, with male predominance (male 54.79% vs female 45.21%) and increasing incidence correlating with advanced age. A total of 606 isolates were identified as 21 NTM species, predominantly Mycobacterium avium complex (MAC) (73.1%), Mycobacterium abscessus complex (MABC) (12.4%), and Mycobacterium kansasii (M. kansasii) (8.1%). MAC showed > 95% susceptibility to rifamycins, clarithromycin, amikacin, and linezolid, with resistance to imipenem/tetracyclines. MABC maintained > 80% susceptibility to linezolid, amikacin, clarithromycin, cefixime, and moxifloxacin but imipenem resistance. M. kansasii demonstrated 30.6% sulfamethoxazole susceptibility versus > 80% for clarithromycin, amikacin, fluoroquinolones, and linezolid. Optimal combinations: rifamycin-clarithromycin-linezolid (MAC) and linezolid-amikacin-ethambutol (MABC). Conclusions: NTM species exhibit distinct antimicrobial profiles, with clarithromycin, linezolid, and amikacin demonstrating efficacy versus limited activity of imipenem/ sulfamethoxazole. Pulmonary NTM infections necessitate species-specific multidrug regimens guided by AST, while regional susceptibility epidemiology informs evidence-based empirical therapy and controlled trial frameworks.

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