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Clinical and Vaccine Immunology, March 2009, p. 423-426, Vol. 16, No. 3
1071-412X/09/$08.00+0 doi:10.1128/CVI.00009-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.
3)-β-D-Glucan as an Adjunct to Diagnosis in a Mixed Population with Uncommon Proven Invasive Fungal Diseases or with an Unusual Clinical Presentation
Servicio de Microbiología, Hospital Severo Ochoa, Leganés, Madrid,1 Unidad de Micología, Departamento de Microbiología, Hospital Universitario 12 de Octubre, Madrid,2 Departamento de Enfermería I, Universidad del País Vasco, Lejona, Vizcaya,3 Departamento de Inmunología, Microbiología y Parasitología, Facultad de Medicina y Odontología, Universidad del País Vasco, Lejona, Vizcaya, Spain4
Received 15 September 2008/ Accepted 13 January 2009
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3)-β-D-glucan as an adjunct diagnostic tool in 12 patients with proven invasive fungal disease with different risk factors. The infections were due to either uncommon fungal pathogens such as dematiaceous molds (Scedosporium apiospermum, Alternaria infectoria, and Cladosporium macrocarpum) and hyaline septate molds (Fusarium solani and Blastoschizomyces capitatus) or Aspergillus spp. with unusual clinical presentations. |
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Conventional microbiological and radiological techniques that have been used for the diagnosis of IFD are relatively insensitive. Recently, noninvasive culture-independent diagnostic tools have been developed to improve diagnosis and clinical management.
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3)-β-D-Glucan (BG) is a cell wall component of fungi. Its presence in serum and normally sterile body fluids is a marker of IFD and is an indirect mycological criterion in the revised definitions of IFD (4). Different studies have established its diagnostic value in invasive candidiasis and invasive aspergillosis (9, 10). However, currently numerous non-Candida and non-Aspergillus fungi are important causes of IFD in the immunocompromised host, and in this setting, clinical and mycological experience with the use of BG as a tool for diagnosis is scarce (7-11). The aim of this report was to assess the usefulness of BG detection (Fungitell; Associates of Cape Cod, Falmouth, MA) as a diagnostic adjunct in proven IFD in a mixed population with uncommon fungal infections due to emerging dematiaceous and hyaline septate molds (14) or with an unusual clinical presentation.
In this single-center observational study, when there were patients with clinical suspicion of IFD, a prospective diagnostic workup was started. This included high-resolution computed tomography followed, when possible, by biopsies of deep tissues for bacterial, mycobacterial, fungal, and viral cultures. BG detection was performed according to the manufacturer's instructions. A BG level of
80 pg/ml was considered to be positive. Serum assays were performed in triplicate. The galactomannan (GM) assay was performed as recommended by the manufacturer (Platelia Aspergillus assay; Bio-Rad, Marnes La Coquette, France). An index of
0.5 was considered positive.
We herein report the performance of BG and GM reactivity assays (when appropriate) in sera from 12 patients with proven IFD (Table 1). There were seven non-Aspergillus infections, including three Scedosporium apiospermum (clade 4) infections (5), one Alternaria infectoria infection, one Cladosporium macrocarpum infection, one Fusarium solani infection, and one mixed infection by Blastoschizomyces capitatus and Candida kefyr. The samples involved were brain, subcutaneous tissue, peritoneal abscesses, and tissues with disseminated fungal infections (Table 1). Aspergillus species (three isolates of Aspergillus fumigatus, one of Aspergillus versicolor, and one of Aspergillus flavus) caused lung infection, brain abscesses, middle ear mastoiditis, and subungual proximal onychomycosis with subcutaneous involvement (2). Fungi were identified following the guidelines of Gilgado et al. (5) and de Hoog et al. (3).
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TABLE 1. Demographic and clinical findings for 12 patients with proven IFDa
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To the best of our knowledge, patient 4 represents the first reported case of cutaneous alternariasis with BG reactivity. The treatment with oral itraconazole led to clinical cure after 4 weeks, rendering the BG detection negative. Treatment was maintained for a further 3 months, and 1 year after the end of treatment the patient was cured even though immunosuppressed.
Patient 9 had an unusual portal of entry of IFD due to A. fumigatus, as has been reported elsewhere (2). Both markers were positive, and the patient achieved a total cure, possibly due to the introduction of an early treatment that rendered both markers negative.
Patient 6 had a very high fungal load since F. solani was cultured in blood and several nodules in skin. BG was positive, which is in agreement with previously reported studies (7, 9).
Case 8 suggests that since both fungal markers (GM and BG) have limitations for the diagnosis of invasive aspergillosis, the two markers should be combined as diagnostic tools (10).
Patient 7 had fungal peritonitis caused by two different etiologic agents. There is no real consensus on the diagnostic criteria for fungal peritonitis, but in gastrointestinal surgery patients with anastomotic leakage, the isolation of fungi in tissue obtained in a surgical procedure establishes a sound diagnosis, as is the case for this patient (13).
Although the number of patients with invasive aspergillosis was small, BG detection tended to be superior to GM detection in establishing the diagnosis. However, since both BG and GM testing have limitations, detection of both markers should be used in combination to improve the diagnostic workup of the disease (10).
Non-Aspergillus emerging mycelial invasive disease lacks an early indirect diagnosis. However, the majority of these isolates produce high levels of BG in vitro with apparent species-specific BG levels (8).
In nine patients BG positivity appeared a mean of 12 days (range, 5 to 29 days) before the fungal culture was grown. In patient 3, both markers appeared at the same time, and in two patients (patients 9 and 11) BG positivity appeared 2 and 30 days later than the fungal culture, respectively.
As described previously (10), these preliminary results suggest that monitoring BG antigenemia would also be a valuable tool in predicting therapeutic outcome in patients with IFD, since rising levels of BG tended to correspond with treatment failure.
In conclusion, data presented in this report suggest that BG is a useful noninvasive tool for the diagnosis of IFD in patients with uncommon fungal infections or with unusual clinical presentations. All new diagnostic techniques such as BG should be validated against postmortem findings or biopsies of deep tissues because only proven cases of IFD offer the most valuable and sound information.
This investigation was supported by grants from the Fondo de Investigación Sanitaria, Instituto de Salud Carlos III, PI070107 (to A.d.P.), PI070134 (to M.S.C.), and PI070376 (to J.P.); by a grant from the Department of Education, Universities and Research, Basque Government, IT-264-07 (to J.P.); and by an educational grant from Pfizer Spain (to A.d.P.).
Published ahead of print on 21 January 2009. ![]()
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3) β-D-glucan assay as an aid to diagnosis of fungal infections in humans. Clin. Infect. Dis. 41:654-659.[CrossRef][Medline]
3)-β-D-glucan chromogenic assay to diagnosis and therapeutic monitoring of invasive aspergillosis in neutropenic adult patients: a comparison with serial screening for circulating galactomannan. J. Clin. Microbiol. 43:299-305.
3)-β-D-glucan assay for the diagnosis of invasive fungal infections. J. Clin. Microbiol. 46:1009-1013.
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