Bacterial etiology in early re-admission patients with acute exacerbation of chronic obstructive pulmonary disease

Background: Repeatedly hospitalized patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) are often exposed to more antibiotics, but the distribution of pathogenic bacteria in these patients is poorly understood. The objectives of this study were to analyze the distribution of pathogenic bacteria and the risk factors associated with multidrug-resistant (MDR) bacteria infection in early re-admission patients with AECOPD.

Methods: We retrospectively reviewed charts for patients with AECOPD admitted to our hospital between January 2011 and November 2012. The early re-admission group and non-early readmission group were determined by whether patients were readmitted within 31 days after discharge. Detection of potentially pathogenic microorganisms (PPMs) and MDR bacteria were analyzed. Logistic regression analysis was performed to identify independent risk factors for MDR bacteria infection.

Results: PPMs were isolated from 230 (32.0%) cases of respiratory tract specimens; MDR bacteria accounted for 24.7% (57/230). Pseudomonas aeruginosa (43.7%), Klebsiella pneumoniae (15.6%), and Acinetobacter baumannii (12.5%) were the top three PPMs in the early readmission group, while the top three PPMs in the non-early readmission group were K. pneumoniae (23.7%), P. aeruginosa (21.2%), and Streptococcus pneumoniae (17.1%). Multivariate analysis showed that use of antibiotics within 2 weeks (odds ratio [OR] 8.259, 95% confidence interval [CI] 3.056-22.322, p = 0.000) was the independent risk factor for MDR bacteria infection.

Conclusion: Non-fermentative Gram-negative bacilli (NFGNB) and enterobacteria were the predominant bacteria in early readmission patients with AECOPD. The detection rate of MDR bacteria was high which was related to the use of antibiotics within 2 weeks before admission in these patients.