# The Application Value of Bronchoalveolar Lavage Fluid Metagenomic Next‐Generation Sequencing in Moderate‐to‐Severe Bronchiectasis

## TL;DR

This study shows that metagenomic sequencing of bronchoalveolar fluid detects more pathogens and improves treatment in severe bronchiectasis compared to traditional methods.

## Contribution

Demonstrates mNGS's superior diagnostic performance and clinical utility in bronchiectasis compared to conventional techniques.

## Key findings

- mNGS detected pathogens with significantly higher sensitivity and positive detection rates than conventional methods.
- mNGS identified mixed infections more effectively and improved patient outcomes including shorter hospital stays.
- Pseudomonas aeruginosa and Aspergillus fumigatus were the most common pathogens detected by both methods.

## Abstract

Bronchiectasis, a leading chronic airway disease, often worsens due to infections, making rapid pathogen detection crucial. This study aims to evaluate the diagnostic value of bronchoalveolar lavage fluid (BALF) metagenomic next‐generation sequencing (mNGS) in identifying pathogens in moderate‐to‐severe bronchiectasis and compare its advantages to conventional methods.

Fifty‐two hospitalized patients initially diagnosed with moderate‐to‐severe bronchiectasis at Foshan Hospital of Traditional Chinese Medicine from May 2022 to March 2024 were enrolled. Clinical data and BALF samples were collected and subjected to both mNGS and conventional pathogen detection methods. The differences and concordance in pathogen distribution between mNGS and conventional methods, as well as their diagnostic performance, were compared.

The positive detection rate of pathogens by mNGS was significantly higher than that by conventional methods (p < 0.01). Both methods predominantly identified bacterial pathogens, with
Pseudomonas aeruginosa
being the most common bacterium and
Aspergillus fumigatus
the most frequent fungus. However, mNGS detected a broader range of pathogens and demonstrated superior sensitivity in identifying mixed infections (p < 0.01). The sensitivity of mNGS was 66% higher than that of conventional methods (p < 0.01), and the complete concordance rate between the two methods in double‐positive cases was 41.18%. Additionally, mNGS‐guided anti‐infection treatment significantly improves patient symptoms, reduces hospital stays, and lowers costs (p < 0.05).

Compared with conventional methods, BALF mNGS demonstrates higher sensitivity, a greater positive detection rate, superior capability in identifying mixed infections, improved diagnostic performance, and a better guiding effect on anti‐infection treatment in moderate‐to‐severe bronchiectasis.

This study analyzed the clinical data of 52 patients with moderate‐to‐severe bronchiectasis who were admitted to our hospital. It explored the diagnostic value of bronchoalveolar lavage fluid (BALF) metagenomic next‐generation sequencing (mNGS) in identifying infectious pathogens in patients with moderate‐to‐severe bronchiectasis, and clarified the advantages of mNGS over conventional pathogen detection methods.