Aim To comprehensively understand the lung microbiology in bronchiectasis, we presented a meta-analysis to determine the prevalence of bacteria, fungi, and viruses.

Method Six databases were screened to assess lung microbes in adults with non-CF bronchiectasis. Data collection included both culture-based and sequencing approaches. Subgroups were categorized by disease stage: the stable group, the exacerbation group, and unclassified data consolidated into the undetermined group. Culture data were analyzed in random-effects meta-analyses, while sequencing data were processed using QIIME 2.

Results A total of 98 studies were included with data from 54,384 participants worldwide. The most frequently isolated bacteria were Pseudomonas aeruginosa, Haemophilus influenzae, and Streptococcus pneumoniae with prevalence metrics either higher or similar to the stable group versus the exacerbation group. Aspergillus and Candida were the predominant culture-identified fungi with varying distributions among subgroups. Rhinovirus, Influenza A, Parainfluenza, and Coronavirus were commonly reported viruses, but their prevalence exhibited greater variability across body sites than between disease stages. Sequencing data yielded comparable results of culture but lower bacterial community diversity values were more associated with exacerbation risks. Notably, Pseudomonas had a higher relative abundance during exacerbations even under antibiotic pressure.

Conclusion The meta-analysis revealed similar microorganism patterns in both stable and exacerbation states of bronchiectasis. However, variations in microbiological detection methods and sample sites may significantly impact the results.