PURPOSE: Acute exacerbations of COPD (AECOPD) are a significant cause of hospital admissions, morbidity and mortality. This study was conducted to determine the microbiologic etiology of severe COPD exacerbations considering the paucity of microbial data from developing countries.
METHODS: Fifty patients with AECOPD requiring mechanical ventilation were prospectively studied. Pharyngeal and tracheal aspirates, non-bronchoscopic and bronchoscopic bronchoalveolar lavage(NBBAL, BBAL) and protected specimen brush (PSB) were obtained from patients within 48 hours of intubation and subjected to microbiological studies. The associations between various patient characteristics, their outcome and the type of organism isolated were assessed.
RESULTS: The mean age was 62±10 years with male predominance (88%). 72% of patients had pre-existing co-morbidities with mean APACHE II score of 17.8 at admission. 36% patients had infiltrates in the first day chest radiograph (CXR). Overall, microorganisms were isolated in 22 of 50 patients (bacteria- 30%, viruses- 10%, both- 4%). All bacterial isolates were gram negative bacilli (GNB), while viruses showed a wide spectrum. 85% GNB were lactamase producers with the most efficient antimicrobial being cefoperazone- sulbactam. Baseline variables such as age, smoking status, duration of exacerbation, APACHE II score and CXR infiltrates were not associated with isolation of organism. In-patient mortality rate was 55%. Isolation of microbes from the lower respiratory tract on the first day was not associated with the outcome. Mortality was higher in patients with CXR infiltrates on initial presentation, higher leukocyte count, BUN and creatinine with elevated liver enzymes.
CONCLUSION: Gram negative bacteria especially beta-lactamase producers were more frequently isolated in our patients than reported previously. Unlike other studies, community acquired pathogens were not demonstrated, presumably due to the rampant use of empirical antimicrobial therapy. No association between microbial isolation and patient outcome.
CLINICAL IMPLICATIONS: Isolation of GNB implies that patients with severe AECOPD may require prolonged treatment with higher generations of antimicrobials. Also, empirical antimicrobial pre-treatment should be tailored in the wake of an increasing rate of isolation of resistant organisms. Further studies are warranted to clarify this issue.
DISCLOSURE: Pallawi Torka, No Financial Disclosure Information; No Product/Research Disclosure Information