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Mucoid Escherichia coli in cystic fibrosis
Abstract:
Patients with cystic fibrosis commonly harbor in their lungs strains of Pseudomonas aeruginosa that have a mucoid coating considered virtually pathognomonic for the disease. We found that strains of Escherichia coli with a morphologically similar mucoid coating were present in the respiratory tracts of eight (11.8 per cent) of 68 patients with cystic fibrosis whose sputum cultures yielded Esch. coli, as compared with none of 89 patients without cystic fibrosis who had Esch. coli in sputum. Mucoid strains of Esch. coli were also recovered from the stools of five (11.1 per cent) of 45 patients with cystic fibrosis, as compared with one (0.7 per cent) of 150 patients without cystic fibrosis. The mucoid substances purified from Esch. coli were biochemically and antigenically distinct from those of P. aeruginosa. We conclude that the respiratory tract in cystic fibrosis offers an environment conducive to the production of a mucoid coating not only by P. aeruginosa but by other gram-negative bacilli as well.
Insights
Cystic fibrosis patients frequently develop mucoid Pseudomonas aeruginosa. This study found mucoid Escherichia coli in cystic fibrosis patients' respiratory tracts, suggesting the CF lung environment promotes mucoid coating in other bacteria too.
Area of Science:
- Microbiology
- Pulmonology
- Genetics
Background:
- Cystic fibrosis (CF) is a genetic disorder affecting multiple organs, primarily the lungs.
- Mucoid strains of Pseudomonas aeruginosa are commonly found in CF lungs and are associated with disease progression.
- The development of mucoid phenotypes in bacteria is a significant factor in chronic infections.
Purpose of the Study:
- To investigate the prevalence of mucoid strains of Escherichia coli in patients with cystic fibrosis.
- To compare the occurrence of mucoid E. coli in CF patients versus non-CF individuals.
- To determine if the cystic fibrosis lung environment influences the production of mucoid coatings in gram-negative bacilli.
Main Methods:
- Sputum and stool samples were collected from patients with and without cystic fibrosis.
- Bacterial cultures were analyzed for the presence of mucoid strains of Escherichia coli.
- Biochemical and antigenic characterization of purified mucoid substances from E. coli and Pseudomonas aeruginosa.
Main Results:
- Mucoid strains of Escherichia coli were identified in 11.8% of cystic fibrosis patients' respiratory tracts, compared to 0% in controls.
- Mucoid E. coli was also more prevalent in the stools of cystic fibrosis patients (11.1%) than in controls (0.7%).
- The mucoid substances from E. coli were found to be biochemically and antigenically distinct from those of P. aeruginosa.
Conclusions:
- The respiratory tract environment in cystic fibrosis is conducive to the development of mucoid coatings in gram-negative bacilli, not exclusively P. aeruginosa.
- This finding suggests a broader environmental influence on bacterial adaptation in the CF lung.
- Further research into the mechanisms driving mucoid phenotype expression in CF patients is warranted.