Comparative analysis of the lung microbiota in patients with lung cancer, chronic obstructive pulmonary disease, and community-acquired pneumonia

ABSTRACT Respiratory diseases pose a significant global public health challenge. Extensive research indicates that respiratory conditions are influenced by lung microbiota; however, the relationships between alterations in pulmonary microbiota and various respiratory diseases remain unclear. This study explores the characteristics and distinctions of lung microbial communities in patients with lung cancer (LC), chronic obstructive pulmonary disease (COPD), and community-acquired pneumonia (CAP). The research involved 114 patients and employed culturomics and 16S rRNA gene sequencing to analyze bronchoalveolar lavage fluid samples. Through culturomics, 168 bacterial species were identified, with variations in bacterial profiles observed across the different diseases. Sequencing results indicated that the dominant phyla among the three groups were Bacillota , Bacteroidota , Pseudomonadota , Actinomycetota , and Fusobacteriota , consistent with the culturomics findings. Notably, the CAP group exhibited higher species richness compared to the LC and COPD groups, with significant differences in beta-diversity among the three groups. Specific bacterial genera, such as Alloprevotella , Abiotrophia , and Mycoplasma , were distinguished as indicative taxa for the LC, COPD, and CAP groups, respectively. Utilizing random forest modeling and receiver operating characteristic curve analysis, several key bacterial genera were identified as capable of differentiating between these diseases. The study highlights distinct differences in lung microbiota among patients with LC, COPD, and CAP, potentially serving as a reference for diagnosis, suggesting that disease-specific microenvironments may influence local microbial communities, thus providing evidence for associations between lung microbiota and various respiratory diseases that warrant further investigation. IMPORTANCE The human lung microbial community plays a crucial role in various respiratory diseases by regulating the lung’s immune system and maintaining lung homeostasis. However, there is a paucity of comparative studies examining the characteristics of the pulmonary microbiome in common respiratory diseases, such as lung cancer (LC), chronic obstructive pulmonary disease (COPD), and community-acquired pneumonia (CAP). This study aims to explore the differences in lung microbiomes among these conditions. By employing culturomics and 16S rRNA sequencing technology, we identified significant variations in their lung microbiota. Notably, Alloprevotella , Abiotrophia , and Mycoplasma were identified as indicative taxa for the LC, COPD, and CAP groups, respectively. This research is essential for enriching the database of cultivable lung bacteria and investigating the interactions between specific strains and diseases at the species level, and identifying potential biomarkers and therapeutic targets.