Transient aspergillus antigenaemia: think of milk

False-positive results of galactomannan assays in patients administered glucose-containing solutions

Galactomannan (GM) is a polysaccharide cell wall component released by Aspergillus spp., and an immunoenzymatic GM assay is used for the diagnosis of invasive pulmonary aspergillosis. We evaluated the cause of strong positivity for GM in patients with no typical signs of aspergillosis. Repeat assays were performed using different instruments and reagent lots, but there were no differences in results among the assays. Patients with strongly positive GM results were investigated. Medication histories revealed that 14 of 23 patients had been administered total parenteral nutrition solution from one manufacturer and 4 patients had been administered dextrose solution from a different manufacturer before being tested. The results of GM assays conducted on samples of dextrose solution and the glucose fraction of the total parenteral nutrition solution were strongly positive, confirming the causes of the false-positive reactions. We hypothesize that a trace amount of GM was introduced into the glucose-containing solutions because glucoamylase, which is necessary for the saccharification step of glucose synthesis, was derived from Aspergillus niger. To enhance patient care and prevent unnecessary antifungal prescriptions, healthcare providers and manufacturers of healthcare products need to be aware of the possibility of false-positive reactions for GM.

Histoplasma antigen detection in unconfirmed pulmonary tuberculosis and cross-reactivity with Aspergillus antigen in patients and in food in Jakarta, Indonesia

PURPOSE

H. capsulatum is endemic in Indonesia, but the value of Histoplasma antigen detection has not been studied.

PATIENTS AND METHODS

Histoplasma galactomannan (GM) ELISA was applied to sera of patients with unproven pulmonary tuberculosis (TB) and patients with a positive Aspergillus GM. Both Histoplasma and Aspergillus GM tests were performed to determine any possible cross-reaction with certain foods.

RESULTS

Fourteen of 122 (11.5%) sera of patients with newly diagnosed clinical TB were positive for Histoplasma GM. The positivity rate in the serum of patients 5-6 and 12 months after TB diagnosis was 3.8% and 3.5%, respectively. Of 88 positive Aspergillus GM sera, 63 (71.6%) were also positive for Histoplasma GM. All tested foods were positive for Aspergillus GM, while 65% of foods were positive for Histoplasma GM.

CONCLUSION

Galactomannan is widespread in sera and food in Jakarta, possibly related to food consumption. Histoplasma and Aspergillus antigen detection for the diagnosis will require additional means of confirming the diagnosis; negative tests may be more helpful for ruling out invasive histoplasmosis and aspergillosis.

Current State of the Diagnosis of Invasive Pulmonary Aspergillosis in Lung Transplantation

As the number of lung transplants performed worldwide each year continues to grow, the success of this procedure is threatened by the incidence of non-CMV infections such as invasive aspergillosis. Despite tremendous efforts and the availability of numerous diagnostic tests (especially in hematological malignancies) the diagnosis of invasive aspergillosis continues to be a challenge. Lung transplantation remains a unique clinical scenario, where additional host defenses are immunocompromized, making many of the available tests unsuitable. In this review we will navigate through the myriad of diagnostic tests currently available and how they apply to this unique patient population, as well as have a look into what the future holds.

False-positive galactomannan assay in broncho-alveolar lavage after enteral nutrition solution inhalation: a case report

Introduction. Diagnosis of invasive aspergillosis is challenging and the gold standard for definite diagnosis remains histopathological tissue examination. However, invasive procedures such as lung biopsy are often not feasible in critically ill patients. The detection of fungal cell wall components like Aspergillus galactomannan in broncho-alveolar lavage remains a key component of the diagnostic procedure. False-positive of the Aspergillus galactomannan assay is not frequent. Case presentation. We report a case of positive galactomannan in broncho-alveolar lavage fluid after enteral nutrition aspiration without signs of invasive aspergillosis. Galactomannan was positive in the enteral nutrition solution. Conclusion. Physicians should be aware of this previously unrecognized cause of false-positive galactomannan in broncho-alveolar fluid which can result in unnecessary treatments.

Role of Molecular Biomarkers in the Diagnosis of Invasive Fungal Diseases in Children

Invasive fungal diseases are important clinical problems that are often complicated by severe illness and therefore the inability to use invasive measures to definitively diagnose the disease. Tests for a range of fungal biomarkers that do not require an invasive sample-collection procedure have been incorporated into adult clinical practice, but pediatric data and pediatric-specific recommendations for some of these diagnostic tools are lacking. In this review, we summarize the published literature and contemporary strategies for using the biomarkers galactomannan, (1→3)-β-d-glucan, Candida mannan antigen and anti-mannan antibody, and fungal polymerase chain reaction for diagnosing invasive fungal disease in children. Data on biomarker use in neonates and children with cancer, history of hematopoietic stem cell transplant, or primary immunodeficiency are included. Fungal biomarker tests performed on blood, other body fluids, or tissue specimens represent promising adjuncts to the diagnostic armamentarium in populations with a high prevalence of invasive fungal disease, but substantial gaps exist in the correct use and interpretation of these diagnostic tools in pediatric patients.

Adult living-donor liver transplantation for a recipient with a high preoperative 1,3-beta-D-glucan level and positive test result for Aspergillus antigen

The patient was a 45-year-old man with underlying alcoholic liver cirrhosis. Two years prior, he was repeatedly hospitalized for liver failure symptoms and requested a living-donor liver transplantation (LDLT) because of end-stage cirrhosis. A pretransplantation blood test revealed a high 1,3-beta-d-glucan (BDG) value of 102.0 pg/mL (reference value <20.0 pg/mL) and a high blood Aspergillus antigen (AsAg) value of 1.6 cutoff index (COI; reference value <0.5 COI). Contrast-enhanced thoracoabdominal-pelvic computed tomography (CT) and cranial magnetic resonance imaging revealed no fungal infection. However, latent fungal infection could not be ruled out, hence preoperative antifungal agent treatment was administered. BDG and AsAg levels showed a decreasing trend after treatment initiation. However, normalization did not occur; the BDG and AsAg levels were 25.8 pg/mL and 1.0 COI, respectively. Although the possibility of latent fungal infection was judged low, we prophylactically administered antifungal agents after LDLT. The BDG level consistently increased at 35-39 pg/mL until postoperative day 5 but subsequently normalized. The AsAg level was higher than the limit of detection at 5.0 COI on postoperative day 3 but normalized to 0.2 COI on postoperative day 5 and did not subsequently increase. The postoperative course was uneventful despite bacterial pneumonia and the patient was discharged on postoperative day 35. A histopathologic examination (Grocott methenamine silver staining) and a fungal polymerase chain reaction assay were performed for the resected liver, but the results of both were negative. At 9 postoperative months, the patient was making ambulatory follow-up visits. Currently, the BDG and AsAg values remain normal and clinical progress is favorable. We found no reports of LDLT for a recipient with a high preoperative BDG level and positive test result for AsAg. Thus, we report on such a case with a discussion of the literature on the causes of high preoperative BDG and AsAg values.

Galactosaminogalactan, a new immunosuppressive polysaccharide of Aspergillus fumigatus

A new polysaccharide secreted by the human opportunistic fungal pathogen Aspergillus fumigatus has been characterized. Carbohydrate analysis using specific chemical degradations, mass spectrometry, ¹H and ¹³C nuclear magnetic resonance showed that this polysaccharide is a linear heterogeneous galactosaminogalactan composed of α1-4 linked galactose and α1-4 linked N-acetylgalactosamine residues where both monosacharides are randomly distributed and where the percentage of galactose per chain varied from 15 to 60%. This polysaccharide is antigenic and is recognized by a majority of the human population irrespectively of the occurrence of an Aspergillus infection. GalNAc oligosaccharides are an essential epitope of the galactosaminogalactan that explains the universal antibody reaction due to cross reactivity with other antigenic molecules containing GalNAc stretches such as the N-glycans of Campylobacter jejuni. The galactosaminogalactan has no protective effect during Aspergillus infections. Most importantly, the polysaccharide promotes fungal development in immunocompetent mice due to its immunosuppressive activity associated with disminished neutrophil infiltrates.

Aspergillus fumigatus is an opportunistic human fungal pathogen that causes a wide range of diseases including allergic reactions and local or systemic infections such as invasive pulmonary aspergillosis that has emerged in the recent years as a leading cause of infection related mortality among immunocompromised patients. Polysaccharides from the fungal cell wall play essential biological functions in the fungal cell biology and in host-pathogen interactions. Indeed, it has been shown that polysaccharides can modulate the human immune response; some of them (β-glucan and α-glucans) having a protective effect against Aspergillus infection. We report here the purification and chemical characterization of a new antigenic polysaccharide (galactosaminogalactan) produced by A. fumigatus. This polymer is secreted during infection. In murine models of aspergillosis, this galactosaminogalactan is not protective but it is immunosuppressive and favors A. fumigatus infection. Particularly it induces the apoptotic death of neutrophils that are the phagocytes playing an essential role in the killing of fungal pathogens.

Epidemiology of invasive aspergillosis and risk factors in non neutropaenic patients

INTRODUCTION

Invasive aspergillosis is a major cause of mortality in allogeneic bone marrow transplant recipients and patients treated for blood malignancies. The diagnostic tools, treatments and preventive strategies, essentially developed for neutropaenic patients, have not been assessed in populations whose immune systems are considered to be competent.

STATE OF THE ART

Beside the standard picture of chronic Aspergillus infection, the incidence of invasive aspergillosis is increasing in non neutropaenic patients, such as those with chronic lung diseases or systemic disease treated with long-term immunosuppressive drugs and solid organ transplant recipients. This study reviews the specific features of invasive aspergillosis in non neutropaenic subjects (NNS) and discusses the value of the diagnostic tools and treatment in this population.

PROSPECTS

A better understanding of the pathophysiology and the epidemiological characteristics of invasive aspergillosis would provide a means of adapting the staging and classification of the disease for NNS.

CONCLUSIONS

Invasive aspergillosis is under diagnosed in NNS who may already be colonised when they receive immunosuppressive treatment; this can lead to an adverse outcome in patients who are considered to be a moderate risk population.

Galactomannan antigenemia in pediatric oncology patients with invasive aspergillosis

BACKGROUND

Diagnosing invasive aspergillosis is difficult but might be improved by detection of circulating galactomannan. Although galactomannan antigenemia has been well studied in the detection of invasive aspergillosis in adult patients, little is known about the expression of circulating galactomannan in immunocompromised children with invasive aspergillosis.

METHODS

We studied the expression of galactomannan antigen by enzyme immunoassay (EIA) in 990 serum samples from 56 pediatric oncology patients (ages 3 months to 18 years) of whom 17 had proven or probable invasive aspergillosis defined by the European Organization for Research and Treatment of Cancer-Mycoses Study Group criteria. Any sample with a galactomannan EIA Galactomannan index value of > or = 0.5 was considered positive.

RESULTS

At least 1 serum sample was positive for 11 of 17 pediatric oncology patients (65.7% sensitivity, 95% confidence interval: 38.3-85.7) with invasive aspergillosis. Galactomannan EIA was positive in 99 of 304 samples from patients with proven or probable invasive aspergillosis, and 7 of 686 (1.0%) samples from 39 control subjects resulted in a positive galactomannan EIA result. At least 1 sample tested positive in 5 of the 39 controls (12.8%, 95% confidence interval: 4.3-27.4). No significant association between accuracy and patient age was observed. Among the 7 evaluable galactomannan-positive patients with IA, the galactomannan EIA produced a positive result before clinical or radiographic evidence of infection in 6 cases, with a lead-time to diagnosis ranging from 1 day to 34 days (median: 10 days). In the remaining case, a positive galactomannan was observed on the same day as diagnosis by non-EIA methods.

CONCLUSIONS

The presence of circulating galactomannan is predictive of invasive aspergillosis in most pediatric oncology patients. Galactomannan antigenemia may precede clinical, microbiologic, or radiographic evidence of invasive aspergillosis.

Current status of fungal cell wall components in the immunodiagnostics of invasive fungal infections in humans: galactomannan, mannan and (1-->3)-beta-D-glucan antigens

Early diagnosis of fungal infections and the implementation of appropriate treatment represent major issues for clinicians, nowadays. Histopathological demonstration of microorganisms in tissue specimens or growth of fungal agents in culture media is still considered the "gold standard", but obtaining such specimens may be difficult. Several groups have investigated serological assays for cell wall elements unique to fungal organisms in serum or other body fluids to improve diagnostics in patients with haematological malignancies or undergoing haematopoietic stem-cell transplantation. In this review we have concentrated on the currently available assays allowing for detection of highly immunogenic components of fungal cell wall: galactomannan, mannan, and also (1-->3)-beta-D-glucan. Rapid serological tests appear to be useful for screening high-risk haematological patients, since they allow for the early diagnosis of invasive fungal infections, including infections with the most common pathogens such as Aspergillus and Candida. Based on current literature, factors increasing the probability of obtaining false-positive or false-negative results detected by each test were also analysed and tabulated.

Prospective Aspergillus galactomannan antigen testing in pediatric hematopoietic stem cell transplant recipients

BACKGROUND

The galactomannan (GM) assay is an approved noninvasive test for detection of invasive aspergillosis (IA) that has been validated in adult patients with hematologic malignancies who are undergoing bone marrow transplantation. There have been few studies with this assay in pediatric patients, but early reports suggest that there may be differences in the performance such that false-positive GM tests in pediatric patients are more common than in adult patients.

METHODS

We performed a prospective study in pediatric hematopoietic stem cell transplant recipients with twice-weekly sampling for GM detection during the highest risk periods of neutropenia and graft-versus-host disease. We analyzed 826 serum samples from 64 patients, including 15 serum samples from one patient diagnosed with probable IA according to defined criteria.

RESULTS

Twenty of 811 samples tested positive on repeat testing (specificity, 97.5%; 95% CI: 96.2-98.4%) including samples from 8 of 63 patients without clinical evidence of IA according to study criteria (specificity, 87.3%; 95% CI: 76.9-93.4%). Eleven patients received piperacillin/tazobactam therapy, and 4 of the 11 patients had a positive assay result coinciding with the dates of piperacillin/tazobactam administration. When samples from these patients were excluded, specificity increased to 98.4% (95% CI: 97.2-99.1%) by sample and to 91.5% (95% CI: 81.6-96.3%) by patient.

CONCLUSIONS

The GM assay holds promise for early, noninvasive diagnosis of IA in high-risk children and false-positive results were not common or unexplainable. This study supports further validation of this assay in a large-scale, pediatric-dedicated format.

Prevention and monitoring of invasive fungal infections in pediatric patients with cancer and hematologic disorders

BACKGROUND

The occurrence of invasive fungal infection (IFIs) in a pediatric hematology/oncology unit after renovation of the ventilation system, and initiating routine azole antifungal prophylaxis was monitored. In addition, the value of serial screening for Aspergillus galactomannan (GM) for diagnosing invasive aspergillosis was assessed.

PROCEDURE

A total of 98 consecutive high-risk pediatric patients were prospectively surveyed for signs of IFI and weekly monitored for serum GM. The data was not made available to treating physicians.

RESULTS

Only 2 patients had proven and 27 possible IFI based on the European Organization for Research and Treatment of Cancer/Mycoses Study Group definitions. The incidence of proven IFI was 1/31 (3.2%) in the allogeneic stem cell transplant (SCT) (Aspergillus spp), 0/26 in the autologous SCT, and 1/60 (1.6%) in the induction therapy group (C. krusei). GM was detected at least in one tested sample in 12/98 patients (12.2%), in five patients in two or more sequential samples. In the latter group, IFI was proven in one patient and could not be excluded in the others. Four of the five patients belonged to the 31 allogeneic and one to the 26 autologous SCT patients. In patients with only one positive GM test none developed signs of IFI and only one received empirical amphotericin B.

CONCLUSIONS

With the currently used preventative and prophylactic measures, IFI is uncommon in children with high-risk for infection. Regular screening for GM could be useful among allogeneic SCT patients and two positive samples should prompt further investigative procedures and pre-emptive antifungal therapy.

Non–Culture-Based Diagnostics for Opportunistic Fungi

The value of the diagnostic markers galactomannan and 1,3-beta-D-glucan for the diagnosis of opportunistic fungal infections is reviewed in this article. Both markers have undergone clinical evaluation, and increasing insight is emerging with respect to the causes of false-negative or false-positive reactivity. These data will help design protocols in which single or multiple markers are used to identify patients who require antifungal therapy.

Occurrence and kinetics of false-positive Aspergillus galactomannan test results following treatment with beta-lactam antibiotics in patients with hematological disorders

Several reports have described a high rate of false-positive Aspergillus galactomannan (GM) test results for patients treated with piperacillin-tazobactam. In this retrospective study, we first examined the relationships between intravenous administration of three beta-lactam antibiotics and the occurrence of false-positive GM test results in hematology patients. We then estimated the kinetics of clearance of GM after the cessation of treatment. Sequential serum samples from 69 patients that had received beta-lactams were analyzed by using a Platelia Aspergillus test. A significant association was found between GM positivity (>/=0.5) and the administration of beta-lactams (P < 0.0001). The direct role of beta-lactams in patients' serum positivity was assessed by testing 39 batches of beta-lactams, of which 27 were positive for GM. None of the latter were positive according to a fungus- and Aspergillus-specific PCR. The kinetics of the decrease of GM was analyzed on sequential serum samples obtained after treatment. By use of a nonlinear regression model, the average time to negative antigen was assessed to be 5.5 days (95% confidence interval [CI], 4.1 to [7.0]), with a half-life of elimination of GM of 2.4 days (95% CI, 1.8 to 3.0). This study confirms that the administration of beta-lactams containing GM is responsible for false-positive diagnostic results, even up to 5 days after the cessation of treatment.

Evaluation of pan-fungal PCR assay andAspergillusantigen detection in the diagnosis of invasive fungal infections in high risk paediatric cancer patients

Profound and prolonged neutropenia following chemotherapy is a major risk factor for systemic fungal infection. As the early diagnosis of invasive fungal infection (IFI) is difficult, these infections are still associated with high morbidity and mortality. Recently, Pan-fungal polymerase chain reaction (PCR) has been a promising aid in rapid, early diagnosis of IFI. During the past few years, increasing numbers of suspected IFIs were encountered at our institution in patients with prolonged neutropenia after intensified immunosuppressive chemotherapy. The aim of this study was to investigate the diagnostic utility of both the aspergillus galactomannan (GM) antigen and the pan-fungal PCR assay in the diagnosis of IFI in high risk febrile neutropenic paediatric cancer patients. During one year period, 91 febrile neutropenic (FN) paediatric cases at high risk for developing IFI while receiving chemotherapy were investigated at National Cancer Institute, Egypt. These patients were subjected to clinical evaluation, chest CT scan, conventional blood cultures for bacterial and fungal pathogens, aspergillus GM antigen detection and PCR assay utilizing pan-fungal primers. Of the 91 FN episodes, 15 were proven IFI; whereas 27 cases were either probable (n=13) or possible IFI (n=14), and 49 were unlikely to be IFI episodes. Based on positive results for proven/probable IFI and compared to culture results, Pan-fungal PCR showed sensitivity, specificity, positive and negative predictive values of 75%, 92%, 84% and 87%; respectively. Aspergillus antigen test showed a sensitivity of 79%, specificity of 61%, positive and negative predictive values of 54% and 83%; respectively. A negative PCR in the proven and probable cases was closely related to previous antifungal therapy for a prior history of IFI. In patients at high risk for IFI, neither the sensitivity, nor specificity of the GM test was sufficient. The results of PCR assay was reasonably specific but not very sensitive and had a chance of missing the diagnosis of IFI. The PCR assay seems a promising test for objectively defining IFI, but is not recommended as the only tool for diagnosing IFI. Combining microscopy, culture, and PCR may improve the diagnostic outcome.

Bifidobacterial lipoglycan as a new cause for false-positive platelia Aspergillus enzyme-linked immunosorbent assay reactivity

We previously hypothesized that a lipoglycan of Bifidobacterium bifidum subsp. pennsylvanicum cross-reacts with the Platelia Aspergillus (PA) enzyme-linked immunosorbent assay (ELISA) based on the presence of galactofuranosyl epitopes in the cell wall (M. A. S. H. Mennink-Kersten, R. R. Klont, A. Warris, H. J. M. Op den Camp, and P. E. Verweij, Lancet 363:325-327, 2004). We tested this hypothesis by testing bacterial suspensions of different bifidobacterial species and other gram-positive and -negative bacteria with the PA ELISA, which is used to detect circulating galactomannan for the serodiagnosis of invasive aspergillosis. Furthermore, neonatal fecal samples were enumerated for bifidobacteria by fluorescence in situ hybridization (FISH) and tested for PA ELISA reactivity. All bifidobacteria, except B. infantis and B. adolescentis, showed reactivity 6- to 600-fold higher compared to the controls (i.e., Micrococcus luteus and Propionibacterium freudenreichii, which contain a cell wall lipomannan). Eggerthella lenta showed a 25-fold-higher reactivity. ELISA reactivity was clearly shown to be associated with bacterial lipoglycans containing a beta-1,5-galactofuranosyl chain. All neonatal feces showed PA ELISA reactivity and associated numbers of bifidobacteria. Since high concentrations of bifidobacteria are present in the human gut, these bacteria or excreted lipoglycan may cause false serum PA ELISA reactivity in selected patient groups, especially neonates.

Cryptococcus neoformans Galactoxylomannan contains an epitope(s) that is cross-reactive with Aspergillus Galactomannan

We report a case of cryptococcosis in which a serum enzyme-linked immunosorbent assay (ELISA) for Aspergillus galactomannan was positive, with no evidence of aspergillosis. Soluble antigens from 19 Cryptococcus neoformans strains and purified carbohydrates of C. neoformans capsule were thus assayed in the Aspergillus galactomannan ELISA. Antigens from all C. neoformans strains, and purified galactoxylomannan, gave a positive reaction, suggesting that C. neoformans galactoxylomannan contains an epitope(s) that is cross-reactive with Aspergillus galactomannan.

Advances in the molecular and serological diagnosis of invasive fungal infection in haemato-oncology patients

Current laboratory diagnostic methods for invasive fungal infection (IFI) in haemato-oncology patients are insensitive, resulting in late diagnosis and contributing to high mortality. In recent years, progress has been made in the development and evaluation of sensitive sero-diagnostic assays, including detection of genomic DNA sequences and fungal antigens, which aid in a rapid, early diagnosis of IFI. The sensitivity and specificity of the assays vary considerably between studies, highlighting the need to correlate serological results with conventional laboratory tests and clinical or radiological findings. As part of management protocols, these assays may help to confirm the diagnosis of suspected IFI; however, the impact on mortality from IFI may be greatest when they are used to screen high-risk patients. Persistently positive screening results could direct early aggressive antifungal therapy, guided further by radiological and microbiological findings combined with regular clinical review, while the excellent negative predictive value may allow treatment to be withheld in patients with antibiotic resistant neutropenic fever but no other signs of IFI. However, this pre-emptive approach requires evaluation in prospective randomized trials.

Impact of diagnostic markers on early antifungal therapy

PURPOSE OF REVIEW

The early treatment of invasive fungal infection is critical but is hampered by the non-specific nature of clinical and radiological signs and the insensitivity of current laboratory diagnostic methods. If mortality due to invasive fungal infection is to be reduced, new, preemptive therapeutic strategies, targeting those patients at highest risk, are required and these will depend on the development of rapid, sensitive diagnostic methods. Such methods have become available in the form of high-resolution computed tomography scanning and serological and molecular techniques and in this review the authors describe recent studies assessing the utility of these methods and consider their role in management strategies.

RECENT FINDINGS

Sensitive assays for the detection of fungal DNA and antigens such as galactomannan and glucan have been prospectively evaluated in the clinical setting and enable identification of patients at an earlier stage of infection. However, the sensitivity and specificity of the assays vary considerably in different studies, depending on several factors including patient selection and clinical application of the test, and issues regarding the release and circulation of galactomannan and fungal DNA remain to be clarified.

SUMMARY

Rapid serological and molecular diagnostic methods facilitate the early diagnosis of invasive fungal infection and would appear to be most useful when used prospectively to screen high-risk patients. However, in order to determine the optimal approach to treatment it is essential that these tests are incorporated into management strategies and their impact on incidence of invasive fungal infection and clinical outcome evaluated in further clinical trials.

Les aspergilloses cérébrales

INTRODUCTION

The brain is almost always a localization of invasive aspergillosis, after hematogenous spread from pulmonary aspergillosis. Brain aspergilosis is not rare and is one of the worst prognosis factors of invasive aspergillosis.

STATE OF ART

The incidence of this severe mycosis is currently on the rise due to the development of major immunosuppressive treatments. Brain aspergillosis is noteworthy for its vascular tropism, leading to infectious cerebral vasculitis, mainly involving thalamoperforating and lenticulostriate arteries, with a high frequency of thalamic or basal nuclei lesions. Extra-neurologic features that suggest this diagnosis are: i) risk factors for invasive aspergillosis (major or prolonged neutropenia, hematologic malignancies, prolonged corticosteroid treatment, bone marrow or solid organ transplant, AIDS); ii) persistent fever not responding to presumptive antibacterial treatment; iii) respiratory signs (brain aspergillosis is associated with pulmonary aspergillosis in 80 to 95 p. 100 of cases). Perspectives. Two recent major improvements in brain aspergillosis management must be outlined: i) for diagnostic purposes, the development of testing for Aspergillus antigenemia (a non-invasive procedure with good diagnostic value for invasive aspergillosis); ii) for therapeutic purposes, the demonstration that voriconazole is better than amphotericin B in terms of clinical response, tolerance and survival, for all types of invasive aspergillosis, the benefit being probably even greater in case of brain aspergillosis because of the good diffusion of voriconazole into the central nervous system.

CONCLUSIONS

Brain aspergillosis is a severe emerging opportunistic infection for which diagnostic and therapeutic tools have recently improved. Thus, this diagnostic must be suspected early, especially in the immunocompromised patient, in the event of respiratory symptoms and when the brain lesions are localized in the central nuclei and the thalamus.

Treatment with Piperacillin‐Tazobactam and False‐PositiveAspergillusGalactomannan Antigen Test Results for Patients with Hematological Malignancies

We report the occurrence of a high rate of false-positive test results during the surveillance of hematology patients for galactomannan (GM) antigenemia. Among 218 patients surveyed from June 2002 through June 2003, 42 (19.3%) had > or =1 serum sample positive for GM (optical density index, >1.5). Of these patients, 38 had no additional evidence of invasive aspergillosis, and, therefore, their test results were considered to be false-positives. Case-control analysis showed that treatment with piperacillin-tazobactam was the only risk factor significantly associated with receiving false-positive test results. When tested for GM antigen, 3 of 4 piperacillin-tazobactam batches had positive results. Physicians should be aware of the possible interference of treatment with piperacillin-tazobactam when interpreting the results of the GM assay.

False-positive galactomannan platelia Aspergillus test results for patients receiving piperacillin-tazobactam

At the bone marrow transplantation center of the San Martino Hospital (Genoa), we observed an increase in the rate of patients with positive Platelia Aspergillus (PA; Bio-Rad) test results, from 10% (38 of 386 patients) in the period from January 1999 through January 2003 to 36% (21 of 59 patients) in the period from February 2003 through May 2003. Positivity was significantly (P<.001) associated with the administration of piperacillin-tazobactam (PT) (17 [74%] of 23 patients who received PT had positive results vs. 4 [11%] of 36 who did not receive PT). Multivariate analysis found administration of PT ( chi 2=34.7; P<.001) and underlying disease ( chi 2=21.14; P<.001) to be associated with PA positivity. Of 15 PT batches tested, 12 had positive PA test results.

Detection of circulating Aspergillus fumigatus galactomannan: value and limits of the Platelia test for diagnosing invasive aspergillosis

The effectiveness of galactomannan detection with the Platelia test was evaluated in a prospective study of 3,327 sera from 807 patients. The specificity was 99.6% (748 of 751 cases). For the groups of patients with proven and probable invasive aspergillosis, the sensitivity was 50.0% (17 of 34 cases). The disappointing sensitivity associated with the presence of rare false-positive cases underlines the limits of this test.