Microbiological profile of tubercular and nontubercular empyemas and its impact on clinical outcomes: A retrospective analysis of 285 consecutively operated cases

BACKGROUND: Empyema thoracis is an entity seen across all age groups. This study aims at reporting a detailed microbiological profile of “pus and pleural tissue” in patients operated for empyema thoracis and also correlating it with perioperative clinical outcomes. MATERIALS AND METHODS: Patients operated for empyema thoracis between 2012 and 2016 were included in the study. Patients were taken up for surgery after thorough preoperative evaluation. Perioperative outcomes were correlated with the results of microbiological analysis to evaluate their effect on clinical outcomes. RESULTS: In the study, 285 patients were operated. There were 215 males (75.4%) and 70 females (24.6%). Tuberculosis (TB) was responsible for 58.2% of the cases (n = 166). Of 166, 32 patients were mycobacterial culture positive, suggesting 19.28% mycobacterial culture positivity rate. 21.8% of the total mycobacterial cultures were multidrug resistant. TB culture-positive patients had a significantly higher incidence of air leak (P = 0.03), inter-costal drain (ICD) duration (P = 0.03), and higher rates of recurrence (P = 0.03). Nontubercular empyema constituted 119 cases (41.8%). Forty-seven (39.5%) cases were culture positive. Gram-negative organisms were cultured in 30 (63.8%). Pseudomonas aeruginosa was the predominant isolate. Bacterial culture-positive patients had significantly higher conversions (P = 0.03), prolonged postoperative air leak (P = 0.04), and postoperative wound infections. CONCLUSIONS: This study highlights the emergence of Gram-negative organisms in bacterial empyema and emergence of multidrug resistance in tubercular empyema. Clinical outcome correlation revealed increased complications in culture-positive cases in both tubercular and nontubercular empyemas.