Sputum antibiogram in acute exacerbation of chronic obstructive pulmonary disease

Abstract

Background: Bacterial infections are the most common reason for acute exacerbation of chronic obstructive pulmonary disease (AECOPD). This can range from self-limited disease to respiratory failure requiring mechanical ventilation and is associated with increased mortality and morbidity in survivors. Aim: To ascertain common antibiotics effective in AECOPD using sputum bacterial culture and antibiotic susceptibility testing. Materials and Methods: In the present cross-sectional observational study, we analysed the sputum antibiogram in 237 patients who had not received antibiotics in the past 48 hours. Statistical analysis was performed, and the χ2 test was used to determine the associations between categorical variables. A P value ≤0.05 was considered significant. Results: Of 237 sputum samples, 77.2% were mucoid in nature, followed by purulent and mucopurulent sputum in 16.9% and 5.9% of cases, respectively. In the purulent/mucopurulent samples, 85.2% showed positive growth on culture compared to 35% of mucoid samples. Cultures grew single pathogens in 108 cases, and 2 grew multiple pathogens; in 127 cases, no pathogenic organisms were isolated. In all, 41 (37.96%) isolates grew Gram-positive and 67 (62.04%) grew Gram-negative organisms. The most effective antibiotic against Gram-negative bacteria was imipenem (50%) and that against Gram-positive bacteria was vancomycin (70.59%). All isolates were resistant to ampicillin. Conclusion: Sputum culture is a good and simple tool to study the aetiology and complications caused by bacteria in AECOPD. The antibiogram helps in identifying the correct treatment and timely initiation of appropriate antimicrobial therapy, thereby helping reduce mortality and morbidity.

Keywords

• mechanical ventilation
• pulmonary infections
• respiratory failure
• sputum culture