Diagnostic Strategy, Particularly Serology.



Invasive aspergillosis is very difficult to diagnose and in the last decades little progress has been made in diagnosing this infection early in patients with hematological malignancies. Therefore, patients with persistent fever while on broad-spectrum antibiotics or those with new pulmonary infiltrates are treated empirically with antifungal agents. As a consequence, a significant number of patients will receive unnecessary treatment with nephrotoxic or expensive antifungal drugs. A better selection of patients can be obtained if patients are screened systematically during the period of neutropemia for the presence of invasive aspergillosis. Screening of patients by high resolution computed tomography of the chest has been shown to improve outcome. Alternatively, the presence of specific markers can be looked for in the serum or blood of neutropenic patients. The presence of the aspergillus antigen galactomannan, (1-->3)-beta-D-glucan, or aspergillus DNA can be monitored in the blood or serum of patients. Once the marker becomes positive further diagnostic tests and procedures can be employed to confirm and locate the aspergillus infection. Patients with confirmed infection can then be treated pre-emptively. A sensitive sandwich ELISA is commercially available outside the USA and enables the detection of low levels of galactomannan in body fluids of infected patients. Galactomannan may be detected at an early stage of disease and the serum titer corresponds with the clinical response to therapy in most patients. A decision analysis showed that the number of patients that would require antifungal treatment could be reduced significantly if patients were screened prospectively by ELISA and CT scan confirmed the presence of invasive aspergillosis. Clinical trials need to be performed to establish if this approach is feasible in daily practice.

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Full conference title: 

38th Interscience Conference on Antimicrobial Agents and Chemotherapy
    • ICAAC 38th