Aspergillus antigen testing in bone marrow transplant recipients

Invasive Pulmonary Aspergillosis in Chronic Obstructive Pulmonary Disease Exacerbations

Nowadays, reports in the literature support that patients with severe chronic obstructive pulmonary disease (COPD) are at higher risk to develop invasive pulmonary aspergillosis (IPA). However, the interpretation of Aspergillus-positive cultures from the airways in critically ill COPD is still a challenge. Indeed, as the patient could be merely colonized, tissue samples are required to ascertain IPA diagnosis but they are rarely obtained before death. Consequently, diagnosis is often only suspected on the basis of a combination of three elements: clinical characteristics, radiological images (mostly thoracic CT scan), and microbiological, and occasionally serological, results. To facilitate the analysis of these data, several algorithms have been developed, and the best effectiveness has been demonstrated by the Clinical algorithm. This is of importance as IPA prognosis in these patients remains presently very poor and using such an algorithm could promote prompter diagnosis, early initiation of treatment, and subsequently improved outcome.While the most classical presentation of IPA in critically ill COPD patients features a combination of obstructive respiratory failure, antibiotic-resistant pneumonia, recent or chronic corticosteroid therapy, and positive Aspergillus cultures from the lower respiratory tract, the present article will also address less typical presentations and discuss the most appropriate treatments which could alter prognosis.

Pulmonary aspergillosis as opportunistic mycoses in a cohort of human immunodeficiency virus-infected patients: Report from a tertiary care hospital in North India

OBJECTIVE

The incidence of pulmonary aspergillosis in human immunodeficiency virus (HIV)-infected persons is rising. This study was designed to determine the prevalence of pulmonary aspergillosis in a cohort of HIV-positive patients (n = 71) presenting with lower respiratory tract infection at a tertiary care medical center in India.

METHODS

Sputum samples were collected, and potassium hydroxide mount, cultural characteristics, and lactophenol cotton blue preparations were employed to aid in the identification of Aspergillus species. In addition, serum galactomannan antigen testing was also performed.

RESULTS

Pulmonary aspergillosis was diagnosed in 7 patients, five of whom showed a positive antigenemia indicating invasive form of disease. The prevalence of pulmonary aspergillosis was highest in individuals 21-40 years of age (13.3%). The gender-wise prevalence of pulmonary aspergillosis was 18.7% and 7.7% in females and males, respectively. The common chest radiographic findings noted in patients with pulmonary aspergillosis included a normal chest radiograph in 3 (42.8%), infiltrates in 2 (28.6%), and pleural effusion in 2 (28.6%). The common Aspergillus species recovered from sputa of these patients were Aspergillus flavus (4; 57.1%); Aspergillus fumigatus (2; 28.6%), and Aspergillus niger (1; 14.3%). A predisposing lung condition in the form of pulmonary tuberculosis was identified in 2; Pneumocystis carinii pneumonia in 2 and a dual tubercular and P. carinii infection in one. The mean CD4 count of these patients was 155.86 ± 119.33 cells/µl (median = 117 cells/µl; range = 18-329 cells/µl).

CONCLUSION

Our findings suggest that Aspergillus species be considered possible etiological agents in HIV-positive patients with pulmonary infection.

Galactomannan detection for invasive aspergillosis in immunocompromised patients

BACKGROUND

Invasive aspergillosis is the most common life-threatening opportunistic invasive mycosis in immunocompromised patients. A test for invasive aspergillosis should neither be too invasive nor too great a burden for the already weakened patient. The serum galactomannan enzyme-linked immunosorbent assay (ELISA) seems to have the potential to meet both requirements.

OBJECTIVES

To obtain summary estimates of the diagnostic accuracy of galactomannan detection in serum for the diagnosis of invasive aspergillosis.

SEARCH METHODS

We searched MEDLINE, EMBASE and Web of Science with both MeSH terms and text words for both aspergillosis and the sandwich ELISA. We checked the reference lists of included studies and review articles for additional studies. We conducted the searches in February 2014.

SELECTION CRITERIA

We included cross-sectional studies, case-control designs and consecutive series of patients assessing the diagnostic accuracy of galactomannan detection for the diagnosis of invasive aspergillosis in patients with neutropenia or patients whose neutrophils are functionally compromised. The reference standard was composed of the criteria given by the European Organization for Research and Treatment of Cancer (EORTC) and the Mycoses Study Group (MSG).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed quality and extracted data. We carried out meta-analysis using the bivariate method. We investigated sources of heterogeneity by adding potential sources of heterogeneity to the model as covariates.

MAIN RESULTS

We included 54 studies in the review (50 in the meta-analyses), containing 5660 patients, of whom 586 had proven or probable invasive aspergillosis. When using an optical density index (ODI) of 0.5 as a cut-off value, the sensitivity of the test was 82% (73% to 90%) and the specificity was 81% (72% to 90%). At a cut-off value of 1.0 ODI, the sensitivity was 72% (65% to 80%) and the specificity was 88% (84% to 92%). At a cut-off value of 1.5 ODI, the sensitivity was 61% (47% to 75%) and the specificity was 93% (89% to 97%). None of the potential sources of heterogeneity had a statistically significant effect on either sensitivity or specificity.

AUTHORS' CONCLUSIONS

If we used the test at a cut-off value of 0.5 ODI in a population of 100 patients with a disease prevalence of 9% (overall median prevalence), two patients who have invasive aspergillosis would be missed (sensitivity 82%, 18% false negatives), and 17 patients would be treated unnecessarily or referred unnecessarily for further testing (specificity 81%, 19% false negatives). If we used the test at a cut-off value of 1.5 in the same population, that would mean that four invasive aspergillosis patients would be missed (sensitivity 61%, 39% false negatives), and six patients would be treated or referred for further testing unnecessarily (specificity 93%, 7% false negatives). These numbers should, however, be interpreted with caution because the results were very heterogeneous.

Aspergillus Polymerase Chain Reaction: Systematic Review of Evidence for Clinical Use in Comparison With Antigen Testing

BACKGROUND

Aspergillus polymerase chain reaction (PCR) was excluded from the European Organisation for the Research and Treatment of Cancer/Mycoses Study Group (EORTC/MSG) definitions of invasive fungal disease because of limited standardization and validation. The definitions are being revised.

METHODS

A systematic literature review was performed to identify analytical and clinical information available on inclusion of galactomannan enzyme immunoassay (GM-EIA) (2002) and β-d-glucan (2008), providing a minimal threshold when considering PCR. Categorical parameters and statistical performance were compared.

RESULTS

When incorporated, GM-EIA and β-d-glucan sensitivities and specificities for diagnosing invasive aspergillosis were 81.6% and 91.6%, and 76.9% and 89.4%, respectively. Aspergillus PCR has similar sensitivity and specificity (76.8%-88.0% and 75.0%-94.5%, respectively) and comparable utility. Methodological recommendations and commercial PCR assays assist standardization. Although all tests have limitations, currently, PCR is the only test with independent quality control.

CONCLUSIONS

We propose that there is sufficient evidence that is at least equivalent to that used to include GM-EIA and β-d-glucan testing, and that PCR is now mature enough for inclusion in the EORTC/MSG definitions.

Efficacy outcomes in a randomised trial of liposomal amphotericin B based on revised EORTC/MSG 2008 definitions of invasive mould disease

In 2008, the European Organisation for Research and Treatment of Cancer/Mycoses Study Group (EORTC/MSG) published revised definitions for diagnosing invasive fungal disease. A previous prospective trial of liposomal amphotericin B for invasive mould disease (AmBiLoad) used modified EORTC/MSG 2002 criteria. We wished to re-evaluate the response and survival based on the revised definitions to compare the outcomes of early vs. late treatment. Patients who had received an allogeneic haematopoietic stem cell transplant or who were neutropaenic (absolute neutrophil count <500 μl(-1) within 14 days of study entry) had been recruited on the basis of a halo or air crescent sign on chest computerised tomography. Originally classified as probable invasive mould disease, they were categorised as possible invasive mould disease using 2008 criteria. Patients had received liposomal amphotericin B at either 3 or 10 mg kg(-1) QD for 14 days, followed by 3 mg kg(-1) QD. Response at end of treatment and the 12-week survival were re-calculated according to 2008 definitions. Six-week survival was estimated by Kaplan-Meier analysis. Of 201 patients with invasive mould disease, 118 (59%) had a diagnosis based on halo signs (possible cases). Mycological evidence was present in 83 (41%) cases (probable/proven cases). Survival rates at 12 weeks for possible vs. probable/proven cases in the 3 mg kg(-1) QD group were 82% vs. 58% (P = 0.006), and 65% vs. 50% (P = 0.15) in the 10 mg kg(-1) QD group. At 6 weeks, rates were 87% vs. 69% in the 3 mg kg(-1) QD group (P = 0.009), and 75% vs. 61% in the 10 mg kg(-1) QD group (P = 0.01). Patients with possible invasive mould disease based on EORTC/MSG 2008 criteria had improved survival rates compared with those treated for probable/proven invasive mould disease. As possible invasive mould disease probably reflects an early-stage of disease, a better outcome might be expected when treatment with liposomal amphotericin B is started preemptively.

Galactomannan detection for invasive aspergillosis in immunocompromized patients

BACKGROUND

Invasive aspergillosis (IA) is the most common life-threatening opportunistic invasive mycosis in immunocompromized patients. A test for IA needs to be not too invasive and not too big a burden for the already weakened patient. The serum galactomannan ELISA seems to have potential for both requirements.

OBJECTIVES

To obtain summary estimates of the diagnostic accuracy of galactomannan detection in serum for the diagnosis of IA.

SEARCH STRATEGY

We searched MEDLINE, EMBASE and Web of Science with both Medical Headings and text words for both aspergillosis and the sandwich ELISA. We checked reference lists of included studies and review articles for additional studies.

SELECTION CRITERIA

Cross-sectional studies, case-control designs and consecutive series of patients assessing the diagnostic accuracy of galactomannan detection for the diagnosis of IA in patients with neutropenia or patients whose neutrophils are functionally compromised were included. The reference standard was composed of the criteria given by the European Organization for Research and Treatment of Cancer (EORTC) and the Mycoses Study Group (MSG).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed quality and extracted data

MAIN RESULTS

Thirty studies were included in the meta-analyses, with a median prevalence of IA (proven or probable) of 7.7%. Seven of these (901 patients) reported results for an Optical Density Index (ODI) of 0.5 as cut-off value. The overall sensitivity in these studies was 78% (61% to 89%) and overall specificity was 81% (72% to 88%). Twelve studies (1744 patients) reported the results for cut-off value of 1.0 ODI, overall sensitivity was 75% (59% to 86%) and mean specificity 91% (84% to 95%). Seventeen studies (2600 patients) reported the results for cut-off value 1.5 ODI, sensitivity was 64% (50% to 77%) and mean specificity 95% (91% to 97%).

AUTHORS' CONCLUSIONS

At a cut-off value 0.5 ODI in a population of 100 patients with a disease prevalence of 8% (overall median prevalence), 2 patients who have IA, will be missed (sensitivity 78%, 22% false negatives), and 17 patients will be treated or further referred unnecessarily (specificity of 81%, 19% false negatives). If we use the test at cut-off value 1.5 in the same population, that will mean that 3 IA patients will be missed (sensitivity 64%, 36% false negatives) and 5 patients will be treated or referred unnecessarily (specificity of 95%, 5% false negatives). These numbers should however be interpreted with caution, because the results were very heterogeneous.

Invasive aspergillosis: epidemiology, diagnosis and management in immunocompromised patients

Morbidity and mortality caused by invasive Aspergillus infections are increasing. This is because of the higher number of patients with malignancies treated with intensive immunosuppressive therapy regimens as well as their improved survival from formerly fatal bacterial infections, and the rising number of patients undergoing allogeneic haematopoietic stem cell or organ transplantation. Early initiation of effective systemic antifungal treatment is essential for a successful clinical outcome in these patients; however, clinical clues for diagnosis are sparse and early microbiological proof of invasive aspergillosis (IA) is rare. Clinical diagnosis is based on pulmonary CT scan findings and non-culture based diagnostic techniques such as galactomannan or DNA detection in blood or bronchoalveolar lavage samples. Most promising outcomes can be expected in patients at high risk for aspergillosis in whom antifungal treatment has been started pre-emptively, backed up by laboratory and imaging findings. The gold standard of systemic antifungal treatment is voriconazole, which has been proven to be significantly superior to conventional amphotericin B and has led to a profound improvement of survival rates in patients with cerebral aspergillosis. Liposomal amphotericin B at standard dosages appears to be a suitable alternative for primary treatment, while caspofungin, amphotericin B lipid complex or posaconazole have shown partial or complete response in patients who had been refractory to or intolerant of primary antifungal therapy. Combination therapy with two antifungal compounds may be a promising future strategy for first-line treatment. Lung resection helps to prevent fatal haemorrhage in single patients with pulmonary lesions located in close proximity to larger blood vessels, but is primarily considered for reducing the risk of relapse during subsequent periods of severe immunosuppression. Strict reverse isolation appears to reduce the incidence of aspergillosis in allogeneic stem cell transplant recipients and patients with acute myeloid leukaemia undergoing aggressive anticancer therapy. Well designed, prospective randomised studies on infection control measures effective to prevent aspergillosis are lacking. Prophylactic systemic antifungal treatment with posaconazole significantly improves survival and reduces IA in acute myeloid leukaemia patients and reduces aspergillosis incidence rates in patients with intermediate-to-severe graft-versus-host reaction emerging after allogeneic haematopoietic stem cell transplantation. Voriconazole prophylaxis may be suitable for prevention of IA as well; however, the results of large clinical trials are still awaited.

Advances in the serological diagnosis of invasive Aspergillus infections in patients with haematological disorders

A reliable diagnosis of invasive aspergillosis in patients with haematological malignancies is seldom achieved antemortem. Conventional laboratory diagnostic methods are insensitive and time-consuming, resulting in late diagnosis and treatment and contributing to unacceptably high mortality. As a result, routine antifungal prophylaxis and early empirical treatment have been recommended. However, overtreatment associated with these strategies results in increased toxicity and cost. The use of sensitive and rapid non-culture-based diagnostic assays, such as detection of Aspergillus antigens (galactomannan, beta-D-glucan) or detection of genomic DNA sequences may allow a shift in emphasis from empirical to pre-emptive therapy, especially when substantiated by suggestive radiological findings. These new tools may be used to confirm a presumed diagnosis of invasive aspergillosis, or, when used to screen high-risk patients, may identify an infection at the early stage of disease. The excellent negative predictive value of these assays should convince clinicians to withhold antifungal therapy in persistently febrile neutropenic patients with no other signs of fungal infection. On the other hand, consecutive positive results in a high-risk population should at least trigger a complete diagnostic work-up. This review will focus on the diagnostic utility as well as on the pitfalls of serial screening for the presence of circulating fungal antigens in haematology patients.

Update on the contribution of galactomannan for the diagnosis of invasive aspergillosis

The diagnosis of invasive fungal infections (IFI) remains a challenge, particularly for diseases caused by filamentous fungi such as Aspergillus species. Unfortunately, many patients affected by these conditions are not identified before autopsy. Therefore, there is a need for new diagnostic methods for IFI. Galactomannan is a soluble antigen released during hyphal growth in tissues. A commercially available sandwich ELISA assay that detects galactomannan has been used in Europe for many years and is now approved for use in the USA. The test has an excellent negative predictive value in the detection of invasive aspergillosis (IA) in high-risk patients. In addition, it is more sensitive than culture and allows IA to be diagnosed before clinical manifestations occur. However, false-negative and false-positive results in certain populations are the main limitations to its use. The purpose of this review is to summarize the current knowledge about galactomannan testing in patients at risk for IA.

Optimization of the cutoff value for the Aspergillus double-sandwich enzyme immunoassay

BACKGROUND

Many health care centers worldwide use the Platelia Aspergillus enzyme immunoassay (PA-EIA; Bio-Rad Laboratories) for diagnosis of invasive aspergillosis (IA). A cutoff optical density (OD) index of 1.5 was originally recommended by the manufacturer, but in practice, most institutions use lower cutoff values. Moreover, a cutoff OD index of 0.5 was recently approved in the United States. In the present study, we set out to optimize the cutoff level by performing a retrospective analysis of PA-EIA values for samples that had been obtained prospectively from adult patients at risk for IA at 2 European health care centers.

METHODS

In total, 239 treatment episodes were included of which there were 19 episodes of proven IA and 19 episodes of probable IA. Per-episode and per-test analyses and receiver operating characteristic curves were used to determine the optimal cutoff value.

RESULTS

In the per-episode analysis, lowering the cutoff OD index for positivity from 1.5 to 0.5 increased the overall sensitivity by 21% (from 76.3% to 97.4%) but decreased the overall specificity by 7% (from 97.5% to 90.5%). Requiring 2 consecutive samples with an OD index > or = 0.5 resulted in the highest test accuracy, with an improved positive predictive value. At a cutoff OD index of 0.5, the antigen test result was positive during the week before conventional diagnosis in 65% of cases and during the week of diagnosis in 79.5% of cases.

CONCLUSIONS

A cutoff OD index of 0.5--identical to the approved cutoff in the United States--improves the overall performance of the PA-EIA for adult hematology patients.

Pulmonary complications of haematopoietic cell transplantation in children

Paediatric haematopoietic cell transplantation has experienced significant advances in the last few decades. However, pulmonary complications are an important limitation to the efficacy of this intervention, contributing to post-transplantation morbidity and mortality. Such complications persist even in experienced centres and occur in adult and paediatric recipients. This review identifies the paediatric pulmonary complications that are commonly seen following haematopoietic cell transplantation and addresses both infectious and non-infectious aetiologies and their clinical manifestations, evaluation, and potential therapy. Ultimately, improvement in outcomes will require attention to immunosuppression as well as traditional diagnostic procedures and treatment. This article aims to review the current state of pulmonary complications post-transplantation, to examine the impact of our recent advances and changes in treatment, and to identify potential future therapies and hypothesise what role these might have on long-term survival.

Serial Aspergillus antigen monitoring in pediatric bone marrow transplant patients

Invasive aspergillosis carries a high mortality rate in immunocompromised patients, such as bone marrow transplant patients. Favorable outcomes are dependent on early detection and treatment. Positive galactomannan antigenemia has been included as a microbiological criterion for probable or possible diagnosis of invasive aspergillosis. Detection of circulating Aspergillus DNA in the first positive galactomannan sample, with serial monitoring, could help in diagnosis of invasive aspergillosis in bone marrow transplant patients. Morbidity and mortality from aspergillosis can possibly be reduced if an early diagnosis is made and appropriate treatment initiated. An effective and accurate way of early detection of invasive aspergillosis is serial Aspergillus antigen monitoring.

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.

Galactomannan does not precede major signs on a pulmonary computerized tomographic scan suggestive of invasive aspergillosis in patients with hematological malignancies

BACKGROUND

Detection of serum galactomannan (GM) antigen and presence of the halo sign on a pulmonary computerized tomographic (CT) scan have a high specificity but a low sensitivity to diagnose invasive aspergillosis (IA) in patients at risk for this disease. To our knowledge, the relationship between the time at which pulmonary infiltrates are detected by CT and the time at which GM antigens are detected by enzyme immunoassay (EIA) has not been studied.

METHODS

In a prospective study, tests for detection of GM were performed twice weekly for patients with hematological malignancies who had undergone hematopoetic stem cell transplantation (HSCT) or had received induction and/or consolidation chemotherapy. A pulmonary CT scan was performed once weekly. Infiltrates were defined as either major or minor signs. IA was classified as proven, probable, or possible, in accordance with the definition stated by the European Organization for Research and Treatment of Cancer-Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group.

RESULTS

We analyzed 161 episodes of infection in 107 patients (65 allogeneic HSCT recipients, 30 autologous HSCT recipients, and 66 induction and/or consolidation chemotherapy recipients). A total of 109 episodes with no IA, 32 episodes with possible IA, and 20 episodes with probable or proven IA were identified. Minor pulmonary signs were detected by CT in 70 episodes (43%), and major pulmonary signs were detected by CT in 11 episodes (7%). Univariate and multivariate analyses revealed no significant association between detection of GM by EIA and detection of abnormal pulmonary signs by CT. A significant association was found between GM levels and receipt of piperacillin-tazobactam. GM test results were not positive before major signs were seen on CT images. Only 7 (10%) of 70 patients with minor pulmonary signs had positive GM test results before detection of the greatest pathologic change by CT.

CONCLUSIONS

We show that detection of GM by EIA does not precede detection of major lesions by pulmonary CT. In the clinical setting, the decision to administer mold-active treatment should based on detection of new pulmonary infiltrates on CT performed early during infection, rather than on results of EIA for detection of GM.

Workload due to Aspergillus fumigatus and significance of the organism in the microbiology laboratory of a general hospital

The increase in the immunocompromised population and the incidence of invasive aspergillosis (IA) are leading to an overinterpretation of the potential clinical significance of many isolates of Aspergillus fumigatus. Our work prospectively assesses the workload of the isolation of A. fumigatus and its clinical significance in the microbiology laboratory of a large teaching hospital. During a 3-year period, all patients from whom A. fumigatus was isolated were prospectively monitored and classified as having IA or "nonsignificant" disease. A point score based on the prediction of five easily obtained laboratory and clinical parameters was applied. We found 404 A. fumigatus isolates in 260 patients (1/1,000 microbiology laboratory samples; 2.1 patients/10,000 admissions). A total of 90 isolates (22.3%) were from patients with IA. Of the 260 patients, 31 (12%) had invasive disease (IA), and the remaining 229 had "nonsignificant" disease. A score based on points for five parameters was applied to our population. It was constructed as follows: "sample obtained by invasive procedures" (1 point), "presence of two or more positive samples from the same patient" (1 point), "leukemia" (2 points), "neutropenia" (5 points), and "corticosteroid treatment" (2 points). Patients with a score of 0 had only a 2.5% probability of IA. Those with a score of 1 or 2 had an increased probability of 10.3%. The probabilities rose to 40% and 70%, respectively, for patients with a score of 3 or 4 or a score of > or = 5. A simple score based on five easily available parameters may be of help to microbiologists and clinicians to predict the risk of IA.

Prospective assessment of Platelia Aspergillus galactomannan antigen for the diagnosis of invasive aspergillosis in lung transplant recipients

The clinical utility of Platelia trade mark Aspergillus galactomannan antigen for the early diagnosis of invasive aspergillosis was prospectively assessed in 70 consecutive lung transplant recipients. Sera were collected twice weekly and tested for galactomannan. Invasive aspergillosis was documented in 17.1% (12/70) of the patients. Using the generalized estimating equation model, at the cutoff value of >or= 0.5, the sensitivity of the test was 30%, specificity 93% with positive and negative likelihood ratios of 4.2 and 0.75, respectively. Increasing the cutoff value to >or= 0.66 yielded a sensitivity of 30%, specificity of 95%, and positive and negative likelihood ratios of 5.5 and 0.74. A total of 14 patients had false-positive tests, including nine who had cystic fibrosis or chronic obstructive pulmonary disease. False-positive tests occurred within 3 days of transplantation in 43% (6/14) of the patients, and within 7 days in 64% (9/14). Thus, the test demonstrated excellent specificity, but a low sensitivity for the diagnosis of aspergillosis in this patient population. Patients with cystic fibrosis or chronic obstructive pulmonary disease may transiently have a positive test in the early post-transplant period.

Galactomannan detection in computerized tomography-based broncho-alveolar lavage fluid and serum in haematological patients at risk for invasive pulmonary aspergillosis

We determined the value of galactomannan (GM) detection in computerized tomography (CT)-based broncho-alveolar lavage (BAL) fluid and serum for the diagnosis of invasive pulmonary aspergillosis (IPA) in haemato-oncological patients with neutropenia. CT of the thorax and BAL were performed systematically at predefined clinical indications. GM was determined by sandwich enzyme-linked immunosorbent assay; the clinicians were unaware of the results. Of 160 patients, 17 patients (10.6%) presented with proven, probable or suspected IPA. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of GM detection in CT-based BAL fluid were all 100%. For GM detection in serially sampled serum, the sensitivity was 47%, the specificity 93%, the PPV 73% and the NPV 82%. A non-blinded follow-up study was performed to validate these results. In this study, 22 of 198 patients (11.1%) presented with IPA, and the sensitivity, specificity, PPV and NPV of GM detection in CT-based BAL fluid were 85%, 100%, 100% and 88% respectively. None of BAL fluids obtained after antifungal treatment of 3 d or more were positive. These results indicate that, when CT is used systematically and at an early stage, GM detection in CT-based BAL fluid has a high PPV for diagnosing IPA early in untreated patients.

Laboratory diagnosis of invasive mycoses

Rising numbers of immunocompromised patients have led to an ever-increasing population at risk of invasive fungal disease. Much has been achieved in the laboratory diagnosis of these infections, such as advances in blood culture systems, and the development of new biochemical, antigen detection assays, and molecular methodologies. More standardized susceptibility testing guidelines provide for better therapeutic interventions. In an era of economic cutbacks in health care, future challenges include the development of cost-effective and technically simplified systems, which provide early detection and identification of common and emerging fungal pathogens. It will, however, take some time to establish the clinical relevance of these new methodologies in different patient populations.

Invasive aspergillosis in cancer

Ten confirmed cases of invasive aspergillosis (IA) in cancer patients were analysed retrospectively. Eight were pulmonary, one was sinonasal and one was cutaneous. The majority of patients had haematological malignancies (7), the remaining three were cases of solid tumours. Fever was present in all 10 cases. Cough and lung signs were present in all eight cases of invasive pulmonary aspergillosis. Haemoptysis was encountered in three of nine cases of pulmonary and sinonasal aspergillosis. Mortality was low (2%). While corticosteroids, antibiotics and anticancer chemotherapy/radiotherapy were factors predisposing the patients to IA, neutropenia was perhaps responsible for their mortality. Seven of the patients had other associated pathogens isolated in culture in addition to Aspergillus spp. Aspergillus fumigatus was the predominant species, followed by A. flavus, A. glaucus, A. nidulans and A. niger. Direct microscopic examination (in six of seven cases) and culture (six of seven cases) correlated well with radiographic and clinical findings in cases with lung involvement. Serology for anti-Aspergillus antibodies performed by gel diffusion precipitin test was positive in one case of sinonasal aspergillosis, wherein only one precipitin band was observed. Correlation of clinical symptoms, consistent radiographic findings and microbiological work-up (the latter including a triad of direct microscopy, culture and serology) are required to arrive at a diagnosis of IA, especially where histology cannot form the mainstay of diagnosis.

A review of nucleic acid-based diagnostic tests for systemic mycoses with an emphasis on polymerase chain reaction-based assays

Nucleic acid-based assays have good potential to complement and enhance the sensitivity and rapidity of conventional methods used in diagnostic mycology. The majority of molecular tests are polymerase chain reaction (PCR)-based assays focusing mainly on the detection of Candida and Aspergillus spp. from clinical samples. DNA extraction and purification procedures should be standardized and can be facilitated by using commercial extraction kits. In general, protocols that target multi-copy genes provide the greatest sensitivity. Objective endpoint assessments of PCR tests using enzyme-linked immunosorbent assays (ELISA) or commercial quantitative systems are capable of rapidly detecting and identifying Candida and Aspergillus spp. Sequencing of PCR products can be used to confirm the identity of amplicons. In cases of suspected invasive aspergillosis, PCR should be performed on both blood and bronchoalveolar lavage fluid to maximize test sensitivity and the positive predictive value. At least two blood specimens should be tested if PCR is undertaken on blood samples alone. In situ hybridization techniques have been used with success to identify fungi in tissue specimens. The wide application of PCR-based assays relies on the introduction of standardized protocols following their evaluation in multicentre, prospective studies.

Aspergillus galactomannan detection in the diagnosis of invasive aspergillosis in cancer patients

PURPOSE

To assess the Aspergillus galactomannan enzyme-linked immunosorbent assay (ELISA) in the diagnosis of invasive aspergillosis (IA) in adult and pediatric oncohematologic patients.

PATIENTS AND METHODS

The study was conducted in four patient groups: those with fever of unknown origin (FUO) during neutropenia, suspected pulmonary infection (PI), or nonpulmonary aspergillosis (NPA) and those undergoing surveillance (S) after hematopoietic stem-cell transplantation (HSCT). IA was classified as definite, probable, or possible, according to European Organization for Research and Treatment of Cancer/Mycosis Study Group definitions.

RESULTS

A total of 3,294 serum samples were collected during 797 episodes (FUO, 261; PI, 297; NPA, 28; and surveillance, 211), and 153 episodes of IA were diagnosed (31 definite, 67 probable, and 55 possible). Three episodes were first suspected from galactomannan ELISA; the remaining 150 cases were diagnosed from clinical or radiologic evidence. Sensitivity of the ELISA was 64.5%, 16.4%, and 25.5% in definite, probable, and possible episodes of IA, respectively, and was lower in patients positive for anti-Aspergillus antibodies than in antibody-negative patients. Most false-positive results occurred in children and in allogeneic HSCT (allo-HSCT) patients. Overall specificity of the ELISA was 94.8%. It was lower in children compared with adults (P <.0001) and in allo-HSCT patients compared with non-allo-HSCT adults (P =.0002). Lowering the ELISA cutoff value from 1.500 to 0.700 seemed more relevant for non-allo-HSCT adults (sensitivity, 73.1%, 44.3%, and 44.7% in definite, probable, and possible IA, respectively; specificity, 94%).

CONCLUSION

Galactomannan ELISA seems less sensitive than previously described, and sensitivity can be further reduced by the presence of anti-Aspergillus antibodies. A new cutoff value for the ELISA of 0.700 is proposed for non-allo-HSCT adults.

[Non-aggressive diagnostic approach to invasive pulmonary aspergillosis in a hematology unit. Retrospective analysis of a series of 16 cases]

PURPOSE

Among neutropenic patients, diagnosis of invasive pulmonary aspergillosis is difficult. Computed tomographic scan, bronchoalveolar lavage and histology are considered invasive procedures, because they represent an infectious risk for these immunocompromised patients.

METHODS

We describe the clinical and noninvasive paraclinical (X-rays, serology) signs of invasive pulmonary aspergillosis, from a retrospective study of 16 cases in a haematology unit.

RESULTS

Outside of fever and chills, cough and polypnea are the earliest signs, followed by chest pain, dyspnea, lung auscultation changes, and haemoptysis. The sensitivity of each sign is higher than 56%. Before the onset of lung auscultation changes, the chest X-ray shows mainly unilateral alveolar infiltrates. Sensitivity of serology is weak (25%), but contributed to early diagnosis in 16.6% of cases.

CONCLUSION

A better knowledge of the invasive pulmonary aspergillosis clinical, radiological and serological signs could help the practician to prescribe an 'invasive' investigation (computed tomographic scan, bronchoalveolar lavage) to confirm the diagnosis of this fungal infection.

Infection control issues after bone marrow transplantation

Bone marrow transplant recipients are at increased risk of a variety of infections from endogenous and exogenous sources. Various practices, including the use of prophylactic agents and a controlled environment are often employed in the name of infection control. Comparable data are lacking because of non-unified definitions of infection and endpoints. Antibiotic-resistant bacteria and fungi are being isolated more frequently as a result of selective pressure.