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Detection of Invasive Pulmonary Aspergillosis in Haematological Malignancy Patients by using Lateral-flow Technology
Published on: March 22, 2012
[Investigation of Aspergillus galactomannan levels in antimicrobial agents]
1Dokuz Eylül Universitesi Tip Fakültesi, Mikrobiyoloji ve Klinik Mikrobiyoloji Anabilim Dali, Izmir. mine.yucesoy@deu.edu.tr
Abstract:
The diagnosis of invasive aspergillosis which is a serious infection of immunocompromized patients, depends on the detection of Aspergillus galactomannan antigen in the serum by enzyme immunoassay (EIA) in routine laboratories. However, it has been previously reported that false positive results in Aspergillus galactomannan test may be obtained in the sera of patients sera receiving piperacillin-tazobactam (PIP-TAZ). The aim of this study was to investigate the presence and levels of Aspergillus galactomannan antigen in the content of PIP-TAZ and some other antimicrobial agents that are often used for the treatment of infections in immunocompromised patients. The level of galactomannan antigen was determined for PIP-TAZ, ampicillin-sulbactam, ampicillin, penicillin G, ceftriaxone, cefepime, imipenem, clarithromycin, ciprofloxacin, vancomycin, gentamicin, trimethoprim-sulfamethoxazole, ornidazole, fluconazole and amphotericin B, by a commercial EIA (Platelia Aspergillus EIA, Bio-Rad, France) kit. Galactomannan index (GI) was estimated with the ratio of absorbance values of antimicrobials to cut-off value and evaluated as positive when GI was found >0.5. Amongst the 15 antibiotics studied, the only positive result was detected for ampicillin with the highest index value (GI = 0.540), followed by PIP-TAZ with a relatively high value (GI = 0.235) even though it was not in the range of positivity. GI values have ranged from 0.011 to 0.188 for the other antibiotics. In conclusion, the use of especially ampicillin (and probably PIP-TAZ) therapy should be questioned in patients whose sera are being tested for Aspergillus galactomannan antigen by EIA in order to evaluate the positive results in terms of false positivities due to cross reactivity.
Insights
Ampicillin and piperacillin-tazobactam may cause false positives in Aspergillus galactomannan tests for invasive aspergillosis diagnosis. Clinicians should consider this cross-reactivity when interpreting EIA results in patients on these antibiotics.
Area of Science:
- Medical Mycology
- Clinical Chemistry
- Infectious Diseases
Background:
- Invasive aspergillosis diagnosis relies on Aspergillus galactomannan antigen detection via enzyme immunoassay (EIA).
- False positive galactomannan test results have been reported in patients receiving piperacillin-tazobactam (PIP-TAZ).
Purpose of the Study:
- To investigate the presence and levels of Aspergillus galactomannan antigen in piperacillin-tazobactam (PIP-TAZ) and other antimicrobial agents.
- To assess potential cross-reactivity of common antibiotics with the Aspergillus galactomannan EIA test.
Main Methods:
- Commercial EIA kit (Platelia Aspergillus EIA) used to determine galactomannan antigen levels.
- Fifteen antimicrobial agents tested, including PIP-TAZ, ampicillin, and others.
- Galactomannan index (GI) calculated; GI > 0.5 considered positive.
Main Results:
- Ampicillin showed the only positive result (GI = 0.540).
- PIP-TAZ exhibited a high, though not positive, GI (0.235).
- Other antibiotics showed lower GI values ranging from 0.011 to 0.188.
Conclusions:
- Ampicillin and potentially PIP-TAZ therapy may lead to false positive Aspergillus galactomannan EIA results.
- Clinicians should consider antibiotic cross-reactivity when interpreting EIA results for invasive aspergillosis.
