Analysis of fungal culture positivity rates from sputum, bronchial washing and tissue specimens in cases of thoracic cavity malignancy

Background Pulmonary mycosis contributes significantly to morbidity and mortality in thoracic malignancies, particularly lung cancer, but diagnosis is often delayed due to non-specific features and limited specimen availability. This study evaluated fungal culture positivity rates from sputum, bronchial washing and tissue specimens in patients with thoracic malignancies in Riau Province. Methods A cross-sectional analytic study was conducted on 57 patients undergoing bronchoscopy between August 2024 and January 2025. Sputum, bronchial washing and tissue specimens were cultured on Sabouraud Dextrose Agar, with Gram staining, 10% potassium hydroxide (KOH), and Vitek confirmation performed for fungal identification. Results Overall, 77.19% of specimens were culture positive. Positivity was highest in sputum (57.89%), followed by bronchial washing (56.14%) and tissue (42.11%). Candida sp. predominated in sputum (49.12%, P = 0.002), whereas Aspergillus sp. was most frequently isolated from tissue (28.07%, P = 0.013). Tissue specimens yielded the highest accuracy, while bronchial washing showed 100% sensitivity and 74.47%, specificity, outperforming sputum for detecting Candida sp. Conclusion Fungal culture positivity varies by specimen type in thoracic malignancies. Tissue specimens are optimal for identifying Aspergillus sp., whereas bronchial washing serves as a reliable alternative for Candida sp. Appropriate specimen selection may improve early diagnosis and clinical management of pulmonary mycoses.