Pseudomonas aeruginosa resistance patterns and clinical outcomes in hospitalized exacerbations of COPD

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) due to Pseudomonas aeruginosa (PA) are associated with worse outcomes. PA antibiotic resistance is important to determine treatment and may influence clinical outcomes. The aim was to study clinical characteristics and outcomes in patients with AECOPD associated with PA based on their antibiotic resistance.

This was a prospective observational study including all patients with AECOPD and positive PA sputum culture admitted in a respiratory ward in a tertiary hospital in Barcelona during 2013-2014. PA was defined as resistant (PA-R) when the antibiogram showed ≥1 resistance.

Four hundred one patients with AECOPD were evaluated. Of them, 54 (13%) had a positive PA sputum culture. Eighty-two per cent were men, median age was 77 (SD 7) years old and FEV1 was less than 36% (SD 17) of predicted value. PA-R was isolated in 35 patients (66%), and PA-sensitive (PA-S) was isolated in 18 (34%) patients. No differences were found in demographics, lung function and comorbidities among groups. PA-R patients were more likely exposed to prior oral corticosteroids (77% vs 44%, P = 0.03) and antibiotics (77% vs 31%, P = 0.01), respectively. AECOPD patients associated with PA-S were more likely to die at 30 days (odds ratio 13.53, 95% confidence interval: 1.14-69.56, P = 0.03) and 90 days (odds ratio 7.09, 95% confidence interval: 1.33-37.89, P = 0.02), respectively.

Pseudomonas aeruginosa-resistant affects patients with severe AECOPD and previous use of corticosteroids and antibiotics. The presence of PA-S is associated with higher mortality. These results may suggest increased virulence in PA-S strains causing acute infections.