# Clinical characteristics, antimicrobial susceptibility patterns, and treatment outcomes of nontuberculous mycobacterial diseases in eastern China: a retrospective cohort study (2019–2022)

## TL;DR

This study examines NTM disease in eastern China, identifying key symptoms, dominant strains, and effective treatments to improve diagnosis and outcomes.

## Contribution

The study provides the first detailed analysis of NTM disease patterns in eastern China, linking species, drug resistance, and treatment duration to outcomes.

## Key findings

- Mycobacterium intracellulare was the dominant NTM strain in the region.
- Treatment for ≥6 months significantly improved patient outcomes compared to shorter durations.
- M. avium complex showed better drug sensitivity than M. chelonae/M. abscessus complex.

## Abstract

Nontuberculous mycobacteria (NTM) are opportunistic pathogens, and the global incidence of NTM diseases has been steadily increasing, posing significant public health challenges. This study retrospectively analyzed clinical data from 136 cases of NTM disease diagnosed at the Zhejiang Provincial Tuberculosis Diagnosis and Treatment Center between 2019 and 2022. It was observed that NTM diseases in this region predominantly affected middle-aged and elderly men, with chronic cough being the principal symptom (74.3%). Bronchiectasis (57.4%) and cavities (38.2%) were the main imaging characteristics. The results of species identification demonstrated that Mycobacterium intracellulare (62.5%) was the dominant strain. Antimicrobial susceptibility testing revealed that Mycobacterium avium complex exhibited relatively favorable sensitivity to clarithromycin, amikacin, ethambutol, rifapentine, rifampicin, and moxifloxacin, while the Mycobacterium chelonae/Mycobacterium abscessus complex showed sensitivity only to amikacin (66.7%). In total, 66.2% of patients received anti-NTM therapy. Patients completing ≥6 months of treatment achieved significantly higher efficacy than those with <6 months (81.82% vs 57.14%, P < 0.01). The study highlights that NTM diseases in this region are predominantly caused by M. intracellulare, with characteristic clinical/imaging features aiding diagnosis. Treatment regimens guided by susceptibility testing and maintained for ≥6 months significantly improve outcomes, emphasizing the importance of species identification and standardized therapeutic duration in NTM management. These findings provide evidence-based insights for optimizing regional NTM diagnosis and treatment strategies.

Nontuberculous mycobacteria (NTM) infections are rising globally, but their characteristics vary by region, complicating diagnosis and treatment. This study addresses a critical gap by analyzing 136 cases from Eastern China, providing the first detailed insights into local NTM disease patterns. By linking pathogen types, drug resistance, and treatment duration to outcomes, this work equips doctors in Eastern China to diagnose faster, choose effective therapies, and improve patient survival. These findings also urge policymakers to prioritize localized data collection and standardized protocols for NTM management globally.