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ELIME (Enzyme Linked Immuno Magnetic Electrochemical) Method for Mycotoxin Detection
Published on: October 23, 2009
Detection of Aspergillus galactomannan antigen in foods and antibiotics
R Ansorg1, R van den Boom, P M Rath
1Institut für Medizinische Mikrobiologie, Universität-GH Essen, Germany.
Abstract:
The specificity of the Pastorex Aspergillus latex agglutination test for the diagnosis of manifest aspergillosis is hampered by the occurrence of false-positive results. In order to prove whether or not the false-positive reactions may be caused by the uptake of the soluble galactomannan antigen from the environment, the presence of the antigen was tested in foods, air samples, antibiotics for therapeutic use and faeces. Reactions of the Aspergillus latex agglutination test were found in 15 (79%) out of 19 samples of meals prepared in a hospital kitchen, in five out of six canned vegetables from a supermarket, in all of six samples of pasta and rice bought in health shops, in the faeces of four bone marrow transplant (BMT) recipients and of four healthy subjects and in one and two batches of the antibiotics co-amoxyclav and piperacillin respectively. The concentration of the antigen in faecal material was calculated to be in the range of 1.2-38.4 micrograms g-1. It is concluded that the faecal galactomannan antigen may reach the circulation in patients with dysfunction of the intestinal mucosal barrier, e.g. BMT recipients, thus leading to diagnostically false-positive antigenaemia.
Insights
False positives in Aspergillus testing may stem from environmental galactomannan antigen. This antigen was detected in food, air, antibiotics, and feces, potentially causing false antigenaemia in immunocompromised patients.
Area of Science:
- Medical Mycology
- Clinical Diagnostics
- Immunology
Background:
- The Pastorex Aspergillus latex agglutination test is crucial for diagnosing aspergillosis.
- False-positive results can complicate diagnosis and patient management.
- Environmental sources of galactomannan antigen are suspected contributors to these false positives.
Purpose of the Study:
- To investigate if environmental uptake of soluble galactomannan antigen causes false-positive reactions in the Aspergillus latex agglutination test.
- To identify potential sources of this antigen in the patient's environment and biological samples.
Main Methods:
- Testing of food samples (hospital meals, canned vegetables, pasta, rice) for galactomannan antigen.
- Analysis of air samples and antibiotic preparations (co-amoxyclav, piperacillin).
- Detection of galactomannan antigen in fecal samples from bone marrow transplant recipients and healthy individuals.
Main Results:
- Galactomannan antigen was detected in 79% of hospital meals, supermarket vegetables, and health food store pasta/rice.
- The antigen was present in feces of both BMT recipients and healthy subjects.
- Positive reactions were also observed in some antibiotic batches.
Conclusions:
- Environmental sources, including food and potentially contaminated antibiotics, harbor galactomannan antigen.
- Faecal galactomannan antigen can translocate into the bloodstream in patients with compromised intestinal barriers (e.g., BMT recipients).
- This translocation can lead to false-positive antigenaemia, impacting the diagnostic accuracy of aspergillosis tests.
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