Related Experiment Videos
Pulsed-field gel electrophoresis analysis of a Pseudomonas aeruginosa pathovar
U Römling1, D Grothues, U Koopmann
1Abteilung Biophysikalische Chemie, Medizinische Hochschule Hannover, Germany.
Abstract:
This paper presents the genome organization and mobility of Pseudomonas aeruginosa strains that had been isolated in half-year intervals from 30 patients with cystic fibrosis since the onset of colonization over a 2- to 8-year period. The chromosomes were digested with DraI or SpeI, separated by pulsed-field gel electrophoresis, blotted and hybridized with probes encoding housekeeping or virulence genes. Strains were differentiated by relatedness of macrorestriction fingerprints. After some turnover of strains during the first two years of colonization, each patient had acquired a set of strains that diversified during the course of the disease. In the majority of patients, two clonal lineages were found to account for colonization in the air passages but each lung habitat was characterized by some specific signature of bands in the macrorestriction fragment pattern.
Insights
Pseudomonas aeruginosa strains in cystic fibrosis patients showed initial turnover, then stable, diversifying lineages. Each patient
Area of Science:
- Microbiology
- Genomics
- Infectious Diseases
Background:
- Pseudomonas aeruginosa is a common opportunistic pathogen in cystic fibrosis (CF) patients.
- Chronic lung infections with P. aeruginosa significantly worsen CF patient outcomes.
- Understanding the genomic dynamics of P. aeruginosa during chronic colonization is crucial for developing effective treatments.
Purpose of the Study:
- To investigate the genome organization and mobility of Pseudomonas aeruginosa strains.
- To track the evolution of P. aeruginosa populations within individual cystic fibrosis patients over time.
- To identify genomic signatures associated with chronic colonization in the CF lung.
Main Methods:
- Longitudinal isolation of P. aeruginosa from 30 CF patients over 2-8 years.
- Macrorestriction analysis (pulsed-field gel electrophoresis) of bacterial chromosomes digested with DraI or SpeI.
- Hybridization with probes for housekeeping and virulence genes to differentiate strains.
- Analysis of macrorestriction fragment patterns to assess strain relatedness and diversity.
Main Results:
- Initial strain turnover observed within the first two years of colonization.
- Each patient typically acquired a dominant set of P. aeruginosa strains that diversified over time.
- Two major clonal lineages frequently accounted for airway colonization in most patients.
- Specific macrorestriction patterns characterized lung habitats within individual patients, indicating localized genomic adaptation.
Conclusions:
- Pseudomonas aeruginosa populations in CF lungs evolve into stable, yet diversifying, clonal lineages.
- Distinct genomic profiles emerge within different lung compartments during chronic infection.
- This study provides insights into the long-term genomic adaptation of P. aeruginosa in the CF environment.