Early differentiation of fungal from bacterial infections in children with hematologic malignancy: a single-center case-control study

Background: Traditional diagnostic approaches may delay the identification of invasive fungal infections (IFI) in children with hematological malignancies (HM) due to inherent limitations, thereby posing life-threatening risks. We evaluated the effectiveness of clinical indicators in differentiating IFI from bacteremia in this pediatric population. Methods: A case group of 50 patients with acute leukemia or lymphoma who developed probable or proven IFI following chemotherapy and had negative bacterial cultures was selected. A control group of 97 patients who developed bacteremia without IFI post-chemotherapy was also included. Results: Among 585 pediatric patients who were hospitalized 9,111 times, the IFI hospitalization rate of 1.02% (93/9,111). By contrast, 104 cases of bacterial infections were reported, with a hospitalization rate of 1.14% (104/9,111). Secondary fever, prolonged antibiotic use ≥ 7 days, history of glucocorticoid therapy, time since chemotherapy, neutropenia duration before diagnosis, fever duration before diagnosis, albumin level, and C-reactive protein (CRP) levels were significantly associated with IFI. Notably, prolonged antibiotic use ≥ 7 days (odds ratio [OR] = 10.879, 95% confidence interval [CI]: 2.033–58.218), time since chemotherapy (OR = 1.193, 95% CI: 1.064–1.336), and fever duration before diagnosis (OR = 2.821, 95% CI: 1.646–4.833) were identified as independent predictors of IFI. A predictive model incorporating these three factors demonstrated improved diagnostic performance, yielding an area under the curve of 0.938 (95% CI: 0.900–0.975), with a sensitivity of 85.1% and specificity of 87.5%. Conclusion: The combination of prolonged antibiotic use ≥ 7 days, time since chemotherapy, and fever duration before diagnosis might help distinguish IFI from bacteremia in pediatric patients with HM.