Changes in the lung bacteriome in relation to antipseudomonal therapy in children with cystic fibrosis

Area of Science:

• Microbiology
• Pulmonology
• Genetics

Background:

• The lung microbiome plays a critical role in cystic fibrosis (CF) pathogenesis.
• Pseudomonas aeruginosa is a common and detrimental pathogen in CF lungs.
• Understanding bacteriome shifts post-antibiotic therapy is crucial for CF management.

Purpose of the Study:

• To evaluate changes in the lung bacteriome of children with CF after antibiotic treatment targeting Pseudomonas aeruginosa.
• To correlate bacteriome composition with clinical parameters such as lung function and white blood cell count.

Main Methods:

• Deep sequencing of the 16S rRNA gene's V4 region to profile bacteriome composition.
• Quantitative real-time PCR to assess total bacterial load and specific pathogen abundance.
• Analysis of sputum samples from nine pediatric CF patients before and after intravenous antibiotic therapy.

Main Results:

• Antipseudomonal antibiotics led to a significant decrease in total bacterial load (16S rDNA) and specific taxa, including Staphylococcus aureus and Streptococcus mitis group members.
• Improvements in forced expiratory volume (FEV1) were positively associated with an increase in Granulicatella sp.
• A negative correlation was observed between total bacterial load and white blood cell count.

Conclusions:

• Antipseudomonal treatment profoundly impacts the CF lung bacteriome, reducing overall bacterial burden and specific opportunistic pathogens.
• The study highlights the potential role of specific, less abundant bacterial species in influencing clinical outcomes in CF.
• Absolute quantification of bacterial load alongside 16S rDNA profiling offers valuable insights into CF lung microbial dynamics.