This study investigates the lung microbiome in healthy smokers and those with chronic obstructive pulmonary disease (COPD) using pyrosequencing of 16S amplicons. The researchers analyzed bronchoalveolar lavage (BAL) samples from never-smokers, healthy smokers, and COPD patients, as well as multiple tissue sites from lung transplant donors. Key findings include: 1. **Bacterial Presence**: Bacteria were detected in all subjects, with no significant differences between groups. 2. **Community Diversity**: Healthy smokers and mild COPD patients had diverse bacterial communities, while moderate and severe COPD patients showed limited community diversity, similar to some healthy subjects. 3. **Core Microbiome**: A core pulmonary bacterial microbiome was identified, including *Pseudomonas*, *Streptococcus*, *Prevotella*, *Fusobacterium*, *Haemophilus*, *Veillonella*, and *Porphyromonas*. 4. **Micro-Anatomic Differences**: Significant micro-anatomic differences in bacterial communities were observed within the same lung of advanced COPD patients, highlighting the importance of local anatomic variation in microbial composition. The study suggests that the lung microbiome is diverse and can vary significantly within the same individual, with potential implications for disease progression and exacerbation.This study investigates the lung microbiome in healthy smokers and those with chronic obstructive pulmonary disease (COPD) using pyrosequencing of 16S amplicons. The researchers analyzed bronchoalveolar lavage (BAL) samples from never-smokers, healthy smokers, and COPD patients, as well as multiple tissue sites from lung transplant donors. Key findings include: 1. **Bacterial Presence**: Bacteria were detected in all subjects, with no significant differences between groups. 2. **Community Diversity**: Healthy smokers and mild COPD patients had diverse bacterial communities, while moderate and severe COPD patients showed limited community diversity, similar to some healthy subjects. 3. **Core Microbiome**: A core pulmonary bacterial microbiome was identified, including *Pseudomonas*, *Streptococcus*, *Prevotella*, *Fusobacterium*, *Haemophilus*, *Veillonella*, and *Porphyromonas*. 4. **Micro-Anatomic Differences**: Significant micro-anatomic differences in bacterial communities were observed within the same lung of advanced COPD patients, highlighting the importance of local anatomic variation in microbial composition. The study suggests that the lung microbiome is diverse and can vary significantly within the same individual, with potential implications for disease progression and exacerbation.