UG FFW Laboratorium voor Farmaceutische Microbiologie
Cystic fibrosis (CF) is a genetic disease in which bacterial lung infections have a major impact on the life expectancy of the patients. The lungs of CF patients are colonized by a collection of microorganisms, called the CF lung microbiome that contains known pathogens and commensal bacteria. One of the most important life threatening bacteria is Pseudomonas aeruginosa (P. aeruginosa), which causes chronic lung infections. P. aeruginosa can form biofilms, which decrease its antibiotic susceptibility. In addition, upon initial colonization of the CF lungs by P. aeruginosa, this bacterium becomes gradually dominant which leads to a decreased bacterial diversity and richness and contributes to a poor disease outcome.
The aim of this study is to gain novel insights into the invasion/ dominance behavior of P. aeruginosa in an artificial CF lung microbiome by assessing if the invasion/dominance is strain-dependent. The two main goals of this study are:
- To investigate the biofilm formation of different P. aeruginosa strains in the presence of an artificial CF lung microbiome
- To determine the invasion of different P. aeruginosa strains in an established multispecies biofilm of an artificial CF lung microbiome.
Biofilm formation of six different P. aeruginosa strains in the presence of an artificial CF lung microbiome was evaluated through plating on selective media at different time points. The artificial lung microbiome contained five commonly co-isolated bacteria (Staphylococcus aureus, Streptococcus anginosus, Achromobacter xylosoxidans, Rothia mucilaginosa, Gemella haemolysans). Then, using statistical analysis, it was determined which P. aeruginosa strain became dominant at each time point and if differences in abundance were observed between the different P. aeruginosa strains.
It was noted the P. aeruginosa strain AA2, an early CF lung isolate, was more dominant, invasive and abundant in an artificial lung microbiome compared to other strains.
This study demonstrates that the dominance and invasion of P. aeruginosa is strain dependent. An early CF isolate (AA2) was more dominant and invasive than late CF isolates, and it will be of interest for future research to potentially confirm this for other isolates. Hence, bacterial factors that contribute to the dominance of P. aeruginosa could be identified which may be a new starting point for therapeutic intervention.