Background & study objectives: Infection is the major cause of acute exacerbation of COPD (AE COPD) of which bacteria are responsible for 30%-50% of cases (Murphy TF. Am Rev Respir dis 1992). There are limited data on bacterial etiology of AE COPD in India. We aimed our study to investigate the frequency of bacterial infection in hospitalized patients of AE COPD, the responsible pathogens and to assess patient's lung function in relation to pathogen isolated.
Method: We prospectively evaluated 72 patients admitted to our institute with AE COPD over one year. Sputum samples were collected and were processed for gram staining and bacterial culture. Pulmonary function testing was done at follow up after 6 weeks (GOLD guidelines 2011).
Results: Bacterial pathogen was isolated in 34 (47.22%) cases. P. aeruginosa (38.23%) was the most predominant organism followed by Klebsiella spp. (29.41%), S. aureus (23.53%), S. pneumonae (5.88%) and Acinetobactor spp (2.94%). There was statistically significant difference observed in relation to age, sputum purulence, number of exacerbations in previous year (p <0.001) and compromised lung function (p <0.05) between patients with and without bacterial infection. Gram negative bacilli (GNB) were predominating in patients with stage III and stage IV COPD (FEV1<50%).
Conclusion: Bacteria are responsible for nearly 50% of AE COPD. Bacterial etiology is different in India from that of western literature. Patients with advanced COPD and compromised lung function had a higher chance of infection with pseudomonas and other GNBs suggesting that such patients may need different pharmacotherapy than those with less severe disease.