Objective: To investigate the role of bacterial infection, antimicrobial sensitivity and antibiotics usage in severe acute exacerbations of COPD requiring mechanical ventilation in the respiratory care unit of the central chest institute of Thailand.
Material and method: All data were analyzed from medical records of 38 patients admitted in RCU of CCIT during 1 November 2008-31 August 2011 with severe acute exacerbations of COPD requiring mechanical ventilation. The tracheobronchial aspirates specimens were collected for Gram stain, quantitative culture and sensitivities testing. The sera were tested for antibodies to Chlamydophila pneumoniae and Mycoplasma pneumoniae with the immunofluorescence test.
Results: Bacterial pathogens were isolated by quantitative culture from 18 of 38 patients (47.3%). Gram-negative bacilli were the predominant organisms. K. pneumoniae was the predominant isolates 7 cases (18.4%) followed by H. influenzae 3 cases and P. aeruginosa 3 cases (7.9% each). A single pathogen was isolated from 12 patients (31.6%), two pathogens were isolated from 5 patients (13.2%) and three pathogens from 1 patient (2.6%). Serological samples were positive for Chlamydophila pneumoniae in 5 (13.2%) cases. 1 of these patients had coinfection with Acinetobacter baumannii. In the RCU, 33 (86.8%) patients were empirically treated with antibiotic. Ceftriaxone was the most commonly used antibiotic.
Conclusion: 57.8% (22/38 cases) of the patients with severe exacerbations in COPD requiring mechanical ventilation caused by bacterial infection, Gram-negative bacilli were the predominant organism with a resistance to commonly used antibiotics of K. pneumoniae, P. aeruginosa, S. aureus, E. coli, A. baumannii, P. mirabilis, S. dysgalactiae and S. pneumoniae. 13.2% of the patients had serological evidence of Chlamydophila pneumoniae infection.