Suitability of bis (methyltio)gliotoxin for Invasive pulmonary aspergillosis diagnosis

Ref ID: 19560

Author:

M Vidal1*, MP Domingo2, MJ Revillo1, L Roc1, J Meis3,4, J Pardo5,6,7, EM Galvez2, A Rezusta1

Author address:

1Departamento Microbiologí­a, Hospital Universitario Miguel Servet, IIS Aragón, Zaragoza, Spain
2Departamento de Procesos Quimicos y Nanotecnologí­a, Instituto de Carboquí­mica ICB-CSIC, Zaragoza,
Spain
3Department of Medical Microbiology and Infecti

Full conference title:

6th Advances Against Aspergillosis 2014

Abstract:

Purpose:
Invasive pulmonary aspergillosis (IPA) is a severe disease caused in 90% of the cases by the mold
Aspergillus fumigatus. It affects not only to inmunocompromised patients but also to critically ill
patients or patients with chronic obstructive pulmonary disease. Its mortality is high, thus being
fundamental its early diagnosis and treatment.
Mold produces severe secondary metabolites which contribute to exacerbate the pathologic effects
observed in the infected host. These metabolites can be measured for IPA diagnosis. One of these
metabolites is bis(methyltio)gliotoxin (bmGT). It remains stable in body fluids and can be measured
for IPA diagnosis.
The objective of this study is to study bmGT suitability for IPA diagnosis. We compared it with
galactomanan(GMN) results.
Methods:
GMN was detected with a commercial assay (Platelia Aspergillus Ag-BioRad). GT and bmGT were
detected with HPTLC. Clinical data from 91 patients was collected. 4 bronchoalveolar lavages
(BAL) and 333 serums were analyzed for both GMN and bmGT. A positive result for GMN was
considered those higher than 0.7ng/ml. Any result of bmGT was considered positive.
Results:
Both techniques were positive for 3 patients (3.2%). Both were negative for 53 patients (58.2%).
GMN was positive and bmGT was negative in 16 patients (17.6%). GMN was negative and bmGT
was positive in 14 patients (15.5%). GMN was weak (<0.7ng/ml) and bmGT was positive in 5 (5.5%) cases. From patients with weak GMN and positive bmGT, one had sinusopathy and improved after voriconazol treatment. One patient had CMV infection according with the ground-glass CT scan image, he also received voriconazol. Impotantly, a patient with nodules and opacities was treated with voriconazol. A. fumigatus was isolated in his bronchoalveolar lavage. Another patient has C. parapsilosis bacteremia. Among the patients with GMN- /bmGT+, one was haematological and had ground-glass image in CT scan. A renal recipient had an oportunstic infection suggesting image and was treated with caspofungin. Two patients showed nodules in CT scan, one of them improved with antibiotics and antivirals and the other had an infection due to Mycobacterium abscessus. Among the group with GMN+/bmGT-, two patients were haematological and had ground-glass image in CT scan but they also had CMV infection, one of this patients received caspofungin. An oncological patient had ground-glass finding and required voriconazol. Three patients had pneumonia and were in treatment with piperaciline-tazobactam, one received voriconazol. Rest of patients didn’t have clinical signs or radiological findings of respiratory infection. However, four of them received antifungal treatment. Conclusion: In 61.4% of the cases two techniques agree. In five cases of weak positives for GMN, bmGT was positive supporting the IPA diagnosis. Curiosly, these five patients received voriconazol. In four of them, treatment with voriconazol produced a decreased in bmGT levels in following sample. Thus, we can conclude that bmGT helps in the diagnosis and evolution monitoring of the patients with suspected IPA. More studies are necessary for clarifying the cases in which two assays are in disagree, probably it is necessary to fix a cutoff for bmGT with the aim of avoiding these false positives results.

Abstract Number: 87

Conference Year: 2014

Link to conference website: http://www.AAA2014.org

New link: NULL

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