Study reveals airway ‘resistome’ larger in those chronic lung disease

Patients with chronic lung diseases carry a higher burden of antibiotic resistance genes in their airways compared with individuals without lung disease, according to a new bronchoscopy-based study conducted by researchers in Norway and Spain.

The study, published March 25 in BMJ Open Respiratory Research, examined the airway “resistome,” the collection of antibiotic resistance genes present in the lung microbiome, to better understand how chronic respiratory conditions may contribute to antimicrobial resistance.

Led by Guri D. Krineland, M.D., at the University of Bergen in Bergen, Norway, the research team noted chronic lung diseases such as chronic obstructive pulmonary disease (COPD), bronchiectasis and severe asthma are often treated with repeated or long-term antibiotic therapy. Although these treatments can help manage symptoms and reduce exacerbations, they may also promote the development of antibiotic resistance within the airway microbiome.

To investigate this phenomenon, the team conducted a bronchoscopy study analyzing lower airway samples from patients with chronic lung disease and compared them with samples from individuals without these conditions. Using advanced genetic sequencing techniques, the team was able to identify and quantify resistance genes present in the airway microbiome.

The results showed that patients with chronic lung disease had a significantly higher abundance and diversity of antibiotic resistance genes compared with controls. The findings, the researchers noted, suggest that the airways of these patients may serve as a reservoir for resistance genes, potentially contributing to treatment challenges over time.

The concept of the resistome attempts to take in the full range of resistance genes present in both harmful and nonharmful bacteria. In the lung, this genetic reservoir can be shaped by factors such as repeated antibiotic exposure, chronic inflammation and changes in the airway environment.

Kringeland and colleagues found that resistance genes were not limited to specific bacterial species but were distributed across a broad range of microbial communities. This highlights the complexity of the airway microbiome and suggests that traditional culture-based testing may underestimate the extent of antibiotic resistance in chronic lung disease.

Importantly, the researchers noted that the higher resistome burden was not solely explained by recent antibiotic use. Instead, it appears to reflect longer-term changes in the airway environment associated with chronic disease, including persistent inflammation and altered microbial ecosystems.

The researchers noted that their study’s results might help explain why patients with chronic lung disease may experience reduced response to antibiotics over time and may require more complex or targeted treatment strategies. Repeated antibiotic exposure creates selective pressure that allows resistant organisms to persist and expand within the airway microbiome.

From a clinical perspective, the study shows the importance of antibiotic stewardship in patients with chronic respiratory disease. Limiting unnecessary antibiotic use and tailoring therapy based on individual patient characteristics may help reduce the development and spread of resistance.

The results also point to the potential role of resistome profiling as a future tool in respiratory medicine. By analyzing the full spectrum of resistance genes in a patient’s airway, clinicians may eventually be able to better predict which antibiotics are likely to be effective and personalize treatment accordingly.

The authors noted several limitations, including the relatively small sample size and the cross-sectional design, which limits the ability to assess how the resistome changes over time. Additionally, bronchoscopy-based sampling, while providing high-quality lower airway data, may not fully capture the variability of the microbiome across different lung regions, they wrote.

Still, the study adds to a growing body of evidence highlighting the role of the airway microbiome in chronic lung disease. Previous research has shown that disruptions in microbial communities and repeated antibiotic exposure can contribute to the development of multidrug resistance in respiratory conditions.

As chronic respiratory diseases continue to affect millions of patients worldwide, understanding how antibiotic resistance develops within the lung will be critical for improving long-term management. The findings suggest that the airway resistome may play a key role in shaping treatment response and disease progression.