Aspergillus positivity in lower respiratory specimens as a predictor of poor prognosis in invasive pulmonary aspergillosis

Background/Aims: In patients with invasive pulmonary aspergillosis (IPA), the clinical significance of culture positivity is unclear. Here we evaluated whether Aspergillus isolation from lower respiratory tract (LRT) specimens was associated with greater disease severity and higher mortality among patients with IPA.Methods: This retrospective cohort study included patients with proven or probable IPA cases. Patients were divided into a culture-positive group with Aspergillus species detected in LRT samples, and a control group with fungus-negative bronchoalveolar lavage (BAL) samples. Clinical characteristics and outcomes were compared between these groups, with propensity score weighting to adjust for baseline differences. The primary end-point was 6-week mortality. Secondary outcomes included galactomannan optical density index (ODI) values, radiologic severity, and 12-week mortality.Results: A total of 119 patients were included—50 (42.0%) with Aspergillus species isolated, and 69 (58.0%) with negative cultures. Compared to the control group, patients in the culture-positive group exhibited significantly higher BAL galactomannan ODI values (5.00 vs. 1.99; p = 0.016), more frequent high-grade radiologic findings (odds ratio [OR], 2.47; 95% confidence interval [CI], 1.31–4.65; p = 0.005), higher 6-week mortality (OR, 2.20; 95% CI, 1.24–3.92; p = 0.007), and higher 12-week mortality (OR, 1.83; 95% CI, 1.03–3.27; p = 0.041). Multivariable analysis confirmed that culture positivity was independently associated with worse radiologic severity and higher 6-week mortality.Conclusions: Aspergillus species isolation from LRT specimens was associated with greater microbiologic burden, more severe radiologic features, and higher mortality. Culture positivity may serve as a readily available prognostic marker in IPA.