Distribution of non-tuberculous Mycobacteria strains and analysis of drug resistance in Lishui City, China.

INTRODUCTION

This study aimed to investigate the distribution and drug resistance of clinically isolated Non-tuberculous Mycobacteria (NTM) strains in Lishui City, and to provide a basis for the development of NTM disease prevention and control strategies in the region.

METHODOLOGY: This retrospective cross-sectional study was performed using NTM-positive clinical specimens collected from patients at a sentinel tuberculosis hospital in Lishui City, Zhejiang Province, China, between January 2023 and December 2024. The isolated NTM strains were identified using a gene chip-based method. Antimicrobial susceptibility testing was conducted using the microbroth dilution method. Statistical analyses were applied to evaluate the isolation rate, species distribution, and drug-resistance patterns of the strains.

RESULTS

The isolation rate of NTM among clinical patients at the sentinel hospital was 18.09% (157/868); The rate was significantly higher in women (26.97%, 72/267) than in men (14.14%, 85/601) (χ2 trend = 20.518, p < 0.001); Nine common NTM species were identified, with Mycobacterium intracellulare being the most prevalent (68.79%, 108/157), followed by Mycobacterium avium (11.46%, 18/157) and Mycobacterium chelonae/abscessus (8.28%, 13/157). Antimicrobial susceptibility testing revealed high resistance rates to several drugs, including imipenem (94.27%, 148/157), doxycycline (94.27%, 148/157), rifampicin (91.72%, 144/157), amoxicillin/clavulanic acid (91.08%, 143/157), meropenem (89.81%, 141/157), cefoxitin (87.90%, 138/157), minocycline (85.99%, 135/157), and ciprofloxacin (85.99%, 135/157). Species-specific differences in resistance patterns were observed.

CONCLUSIONS

The distribution of clinically isolated NTM strains in Lishui City was dominated by Mycobacterium intracellular, Mycobacterium avium, and Mycobacterium chelonae/abscessus. These isolates demonstrated high levels of resistance to commonly used antimicrobial agents, highlighting the need for improved treatment and control strategies.