A new study suggests that Chronic Obstructive Pulmonary Disease and non-cystic fibrosis bronchiectasis patients colonised with Pseudomonas aeruginosa may have less bacterial diversity than previously feared, potentially simplifying antibiotic treatment decisions.
Investigating Antibiotic Resistance Patterns
Researchers analysed respiratory samples from patients hospitalised with chronic lung disease exacerbations who were receiving antibiotic eradication therapy targeting Pseudomonas aeruginosa.
The study focused on whether repeated antibiotic exposure would uncover significant variation in bacterial resistance within individual patients—a concern that can complicate eradication strategies and treatment selection.
High Eradication Rates Observed
Among patients with positive Pseudomonas cultures, short-term microbiological eradication was achieved in more than 90% of cases during or immediately after treatment.
Resistance levels across isolates remained generally low, with limited variability detected within individual patients despite ongoing antibiotic pressure.
Single Dominant Strains Identified
Whole-genome sequencing performed on longitudinal samples from selected patients showed that colonisation was typically driven by a single clonal lineage rather than multiple competing strains.
This finding suggests that, in some patients, analysing a single bacterial isolate may be sufficient to guide antibiotic therapy.
Implications for Clinical Practice
Pseudomonas aeruginosa colonisation is associated with worse outcomes in chronic lung diseases, including increased airway inflammation, exacerbations, and mortality. Concerns about hidden resistance diversity have contributed to uncertainty around eradication approaches.
The new findings suggest that current antibiotic regimens remain broadly effective in selected patients and that extensive multi-isolate testing may not always be necessary.
Caution Over Long-Term Conclusions
The researchers emphasised that the study was relatively small and focused on short-term outcomes. They note that larger longitudinal studies are still needed to better understand persistence, recurrence, and reinfection dynamics over time.
Nevertheless, the study provides reassuring evidence that intra-host resistance heterogeneity may be less common than expected in some chronic lung disease populations, supporting the continued use of targeted eradication strategies.
Reference
Göpel L et al. Antibiotic pressure does not uncover intra-host heterogeneity of Pseudomonas aeruginosa in patients with chronic lung disease. BMC Microbiol. 2026;DOI: 10.1186/s12866-026-05147-9.
