Diagnosis of CNS aspergillosis is difficult and requires invasive techniques. Mortality in BMT patients can be as high as 100% and most patients die within a few days after diagnosis. During 1997, we observed 2 cases of documented (hyaline acute branching septate hyphae infiltrating brain tissues) and 2 of probable CNS aspergillosis in BMT recipients. Probable CNS aspergillosis was defined as the presence of CT or RM cerebral lesions compatible with the disease, with isolation of Aspergillus sp. from nasal cultures. In these patients, all CSF specimens obtained at the onset of neurological symptoms were positive at the ELISA galactomannan antigen detection (Platelia Aspergillus - Sanofi Diagnostics Pasteur France). The ELISA results were tabulated as an index between the optical density (OD) of the sample tested and the OD of the positive control (threshold index = 1). Two patients had 1 and 2, respectively, additional CSF specimens tested during their disease. The CSF antigen load slightly increased (index: 4.06 -> 4.31) in the patient who showed no response to treatment and decreased (index 33.2 -> 5.88 -> 1.6) in the voriconazole-treated long-term survivor. This patient died 57 days after diagnosis, from a VAN-R - E. faecium pneumonia, without evidence of new fungal localizations. By contrast, the Aspergillus galactomannan antigen resulted to be always negative in the CSF of a control group of 17 patients with different diseases, including 7 (23 specimens) with various infective/inflammatory neurological conditions, 5 (5 specimens) with non-infectious CNS diseases and 5 (6 specimens) recipients of BMT without aspergillosis (cyclosporin neurological toxicity with negative TC or MR imaging). In the control group there were 2 cases of Candida meningitis and 1 case of legionellosis. The obtained specificity (100%) encourages the use of this test also in specimens other than serum, since previous uses on sera showed low specificity (81 - 84%) probably due to: (i) a transient antigenemia induced by the immunosuppressive therapy and/or (ii) a cross reactivity with unidentified components in serum. In conclusion, the ELISA galactomannan antigen detection appears to be 100% sensitive and specific when performed on the CSF of patients with cerebral aspergillosis.
Full conference title:
38th Interscience Conference on Antimicrobial Agents and Chemotherapy
- ICAAC 38th