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Long term effect of erythromycin therapy in patients with chronic Pseudomonas aeruginosa infection
T Fujii1, J Kadota, K Kawakami
1Second Department of Internal Medicine, Nagasaki University School of Medicine, Japan.
Background:
Diffuse panbronchiolitis is a chronic infection of the lower respiratory tract common among the Japanese people, with a persistent Pseudomonas aeruginosa infection in the late stage and sustained neutrophil retention in the airways. The long term effect of erythromycin was examined retrospectively in a group of patients with diffuse panbronchiolitis, with and without P aeruginosa infection, and the relationship between drug-induced bacterial clearance and clinical improvement was investigated.
Methods:
The history, daily volume of sputum, type of organisms in sputum cultures, pulmonary function tests, arterial blood gas tensions, and chest radiographs were compared in 16 patients with diffuse panbronchiolitis with P aeruginosa infection and 12 without. The total and differential cell counts in the bronchoalveolar lavage (BAL) fluid were compared in 14 of the 28 patients (five of whom were infected with P aeruginosa) before and after 1-12 months of treatment with erythromycin (600 mg/day). The outcome of treatment in patients showing clearance of organisms on repeated sputum cultures was compared with that in those demonstrating persistence of bacteria in the sputum and patients with normal flora.
Results:
Erythromycin improved respiratory function and arterial blood gas tensions irrespective of the presence or absence of P aeruginosa in the sputum. Treatment also resulted in a reduction in the BAL fluid total cell count and the percentage of neutrophils in both groups of patients. There were no differences between patients in whom the bacteria cleared and those with persistent bacteria or patients with a normal flora with regard to the degree of improvement of respiratory function, arterial blood gas tensions, and BAL fluid cell composition.
Conclusion:
The results suggest that the efficacy of erythromycin in diffuse pan-bronchiolitis may be due to anti-inflammatory effect, independent of P aeruginosa infection or bacterial clearance.
Insights
Erythromycin improves respiratory function in diffuse panbronchiolitis by reducing airway inflammation, regardless of Pseudomonas aeruginosa infection or bacterial clearance. This suggests an anti-inflammatory mechanism is key to its effectiveness.
Area of Science:
- Pulmonology
- Infectious Diseases
- Pharmacology
Background:
- Diffuse panbronchiolitis is a chronic airway disease prevalent in Japan, often complicated by persistent Pseudomonas aeruginosa and neutrophil accumulation.
- Erythromycin's long-term effects were studied in patients with and without P. aeruginosa to understand its impact on bacterial clearance and clinical outcomes.
Purpose of the Study:
- To evaluate the efficacy of long-term erythromycin treatment in diffuse panbronchiolitis.
- To investigate the relationship between bacterial clearance and clinical improvement.
- To explore the underlying mechanism of erythromycin's action in this condition.
Main Methods:
- Retrospective analysis of 28 diffuse panbronchiolitis patients (16 with P. aeruginosa, 12 without).
- Comparison of clinical data, pulmonary function, arterial blood gases, and chest radiographs.
- Analysis of bronchoalveolar lavage (BAL) fluid cell counts before and after 1-12 months of erythromycin treatment (600 mg/day).
Main Results:
- Erythromycin improved respiratory function and arterial blood gases in all patients, irrespective of P. aeruginosa presence.
- Treatment led to decreased total cell counts and neutrophil percentages in BAL fluid.
- No significant differences in improvement were observed based on bacterial clearance or presence of normal flora.
Conclusions:
- Erythromycin's effectiveness in diffuse panbronchiolitis appears to stem from an anti-inflammatory effect.
- This anti-inflammatory action is independent of P. aeruginosa infection or the drug's ability to clear bacteria.
- Erythromycin offers a potential therapeutic strategy targeting airway inflammation in diffuse panbronchiolitis.