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[Inhaled colistin in cystic fibrosis]
Unlabelled:
The clinical course of cystic fibrosis (CF) is characterised by chronic bronchial infection with Pseudomonas aeruginosa. Therapy with inhaled aminoglycosides was introduced to decrease the rate of infectious exacerbations and to delay pulmonary progression. However, development of resistance to aminoglycosides is frequent. Few investigations are available into the resistance profile under treatment with colistin. Antibiotic resistance to colistin was analysed in 44 adult CF patients treated with inhaled colistin. Resistance to aminoglycosides was observed in 86% of cases (38/44) before therapy and decreased to 43% (19/44) under treatment with colistin. Five patients (11%) developed polymyxin resistance. After cessation of therapy pseudomonas became sensitive to polymyxin within a few months and enabled colistin to be reintroduced. In addition, we performed a pilot study analysing the effect of inhaled colistin on the growth of pseudomonas. The number of Pseudomonas aeruginosa decreased from 16.7 million (CFU) bacteria per ml sputum to 2.9 million under therapy with colistin. There was a more than tenfold increase in bacterial counts after inhaled colistin was stopped. Genotyping revealed no change in the type of pseudomonas strains.
Conclusion:
Development of resistance to polymyxin is not rare under long-term treatment with inhaled colistin and requires temporary interruption of therapy. Sputum cultures should therefore be tested regularly for polymyxin resistance in patients treated with inhaled colistin.
Insights
Inhaled colistin therapy for cystic fibrosis (CF) patients reduced Pseudomonas aeruginosa infections but led to polymyxin resistance in 11%. Regular monitoring and temporary treatment breaks are crucial for effective management.
Area of Science:
- Pulmonary Medicine
- Infectious Diseases
- Microbiology
Background:
- Cystic Fibrosis (CF) is marked by chronic Pseudomonas aeruginosa infections.
- Aminoglycoside therapy is common but frequently leads to resistance.
- Limited data exists on colistin resistance profiles during CF treatment.
Purpose of the Study:
- To analyze antibiotic resistance patterns in CF patients treated with inhaled colistin.
- To evaluate the impact of inhaled colistin on Pseudomonas aeruginosa bacterial load.
- To investigate the development of colistin resistance during long-term therapy.
Main Methods:
- Analysis of antibiotic resistance in 44 adult CF patients receiving inhaled colistin.
- Monitoring of aminoglycoside and colistin resistance before, during, and after therapy.
- Pilot study assessing inhaled colistin's effect on Pseudomonas aeruginosa bacterial counts in sputum.
- Genotyping of Pseudomonas aeruginosa strains.
Main Results:
- Aminoglycoside resistance decreased from 86% to 43% during colistin therapy.
- 11% of patients developed polymyxin resistance.
- Inhaled colistin significantly reduced Pseudomonas aeruginosa counts (16.7 million to 2.9 million CFU/ml).
- Bacterial counts increased tenfold after therapy cessation.
- No changes in Pseudomonas aeruginosa strain types were observed via genotyping.
Conclusions:
- Polymyxin resistance is a significant concern with long-term inhaled colistin use in CF.
- Temporary interruption of colistin therapy is necessary when resistance develops.
- Regular sputum culture testing for polymyxin resistance is essential for patients on inhaled colistin.