Microbes responsible for acute exacerbation of COPD

Abstract

This study was designed to find out the microbes responsible for acute exacerbation of chronic obstructive pulmonary disease (COPD). This study was carried out in the National Institute of Diseases of the Chest & Hospital (NIDCH), Dhaka during the period of January 2003 to December 2003. The study was a prospective case control study. There were 88 male and 2 female patients. The majority of the study subjects fell within the range of 50-70 years. All were smokers. 30 stable COPD patients were taken as control for comparison of sputum culture results of acute exacerbated COPD patients. A standard proforma with questionnaire was designed and filled to select patient with COPD. The patients were selected according to the predetermined criteria viz FEV1<70% predicted and FEV1/FVC % <70% of predicted. Morning specimen of sputum was collected after appropriate preparation and physical character of the sputum were noted. Sputum was immediately sent to microbiology lab for culture. Out of 30 stable COPD patients 6(20%) showed positive sputum culture for bacteria, Pseudomonas 3, Klebsiella 1, Streptococcus pneumoniae 1 and Haemophilus influenza 1. Majority of them were Gram-negative organism. Out of 60 patients with acute exacerbation of COPD 39 patients (65%) showed positive culture for bacteria. Pseudomonas 15, Klebsiella 8, Acinetobacter 4, Enterobacter 2, Moraxella catarrhalis 2 and mixed organisms like, Pseudomonas + Klebsiella 2 and Pseudononas + Acinobacter 1. Majority were Gram-negative bacilli viz. Pseudomonas and Klebsiella spp. species. From this study it was concluded that the prevalence of lower airway bacterial colonization in outpatients with stable COPD is high and is mainly due to Gram-negative bacilli like Pseudomonas spp. The greater rate of isolation of pathogenic bacteria in exacerbated COPD than in stable COPD in this study, supports the pathogenic role of bacteria in a proportion of acute exacerbations of chronic obstructive pulmonary disease. The organism commonly play pathogenic role in acute exacerbations of COPD are Pseudomonas and Klebsiella. Acinobacter Moraxella catarrhalis and Enterobacter also contributed in exacerbation of COPD.