Detection of causative organisms on bacterial culture in pleural tissue versus pus in patients with thoracic empyema.

Abstract

Objective: To determine the diagnostic yield of bacterial culture in pleural tissues and pus in patients with pleural empyema and assess the applicability of pleural biopsy in diagnosis. Study Design: Prospective Comparative Observational study, non-probability consecutive sampling. Setting: Department of Pulmonology Out Patients (OPD) and Indoor Wards, Shaikh Zayed Hospital, Federal Postgraduate Medical Institute Lahore, Pakistan. Period: Spanned 18-months, 21 October 2020 to 20 April 2022. Methods: The study included 75 consenting patients (18-70 years) with thoracic empyema, excluding those on antibiotics, with prior pus sample collection >1 week ago, or with pulmonary/extra-pulmonary tuberculosis. Pleural tissue and pus samples were collected for bacterial culture. Diagnostic yields were compared, and data stratified by age, gender, BMI, and symptoms duration, with statistical significance set at P value ≤ 0.05. Results: The study included 75 patients with pleural empyema, with a mean age of 38.1 years and BMI of 25.4 kg/m². Males accounted for 65.3% of the cohort. Pleural tissue samples showed a higher diagnostic yield (84%) compared to pus samples (58.7%). BMI was significantly associated with pleural tissue yield (p=0.040). Klebsiella species, Staphylococcus aureus, Streptococcus species, and E. coli were the most common pathogens isolated from pleural tissues, while Staphylococcus aureus was most common in pus samples. Conclusion: Pleural biopsy with bacterial culture offers a higher diagnostic yield than pus culture alone in patients with thoracic empyema, enhancing diagnostic accuracy and informing treatment strategies effectively.