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

Diagnostic performance of serum galactomannan and β-D-glucan for invasive aspergillosis in suspected patients: A meta-analysis

BACKGROUND

Serum galactomannan (GM) and β-D-glucan (BG) are known markers of invasive aspergillosis (IA). The aim of this meta-analysis was to evaluate the efficiency of serum GM and BG as diagnostic markers of symptomatic IA infection and compare the performance of the combined tests with that of either test individually.

METHODS

A literature search was carried out using PubMed, Web of Science, and EMBASE databases to include relevant studies published in English up to May 2023. The quality assessment was performed using Review Manager 5.3 software. A bivariate model was applied to pool diagnostic parameters using Stata 14.0 software. We used Cochrane I2 index to assess heterogeneity and identify the potential source of heterogeneity by meta-regression. Paired t tests were used to compare the value of GM and BG for IA diagnosis when used in combination or alone.

RESULTS

Sixteen studies were eligible for inclusion in the meta-analysis. For proven or probable IA, serum GM and BG yielded a pooled sensitivity of 0.53 (95% CI 0.40-0.66) vs 0.72 (95% CI 0.61-0.81) and a pooled specificity of 0.94 (95% CI 0.91-0.97) vs 0.82 (95% CI 0.73-0.88). The area under the curve (AUC) of ROC was 0.90 (95% CI 0.87-0.92) vs 0.83 (95% CI 0.80-0.86) for all studies. The pooled sensitivity and specificity for IA diagnosis by combined GM and BG assays (GM/BG) were 0.84 (95% CI 0.69-0.86) and 0.76 (95% CI 0.69-0.81), respectively. The sensitivity of the combined GM/BG test to diagnose IA was higher than of the GM or BG test alone.

CONCLUSION

Serum GM and BG tests had a relatively high accuracy for IA diagnosis in suspected patients. The diagnostic accuracy of both assays is comparable, and the diagnostic sensitivity is further improved by the combined detection of the 2 markers.

Evaluation of the diagnostic accuracy of galactomannan from the bronchoalveolar lavage fluid of patients with suspected invasive pulmonary aspergillosis

BACKGROUND

Several studies to evaluate the accuracy of galactomannan (GM) in bronchoalveolar lavage fluid (BALF) as a diagnostic tool have been carried out; however, there are still controversies about the optimal cut-off point of BALF GM.

AIMS

The objective of this study was to determine the diagnostic accuracy and the optimal cut-off point on BALF GM from patients with suspected invasive pulmonary aspergillosis (IPA) in a tertiary care hospital.

METHODS

A cross-sectional study with 188 patients (≥18 years) that had undergone a bronchoscopy with BAL due to suspected IPA was carried out. IPA was diagnosed according to the EORTC/MSG guidelines.

RESULTS

The optimal optical density cut-off point for BALF GM was 0.67, with sensitivity, specificity, positive predictive value, and negative predictive value of 100%, 70%, 32.3%, and 100%, respectively.

CONCLUSIONS

BALF GM detection proved to be a useful supplementary technique in the early diagnosis of IPA in both neutropenic and non-neutropenic patients.

The Current State of Antifungal Stewardship in Immunocompromised Populations

Inappropriate antifungal use is prevalent and can lead to drug-resistant fungi, expose patients to adverse drug events, and increase healthcare costs. While antimicrobial stewardship programs have traditionally focused on antibiotic use, the need for targeted antifungal stewardship (AFS) intervention has garnered interest in recent years. Despite this, data on AFS in immunocompromised patient populations is limited. This paper will review the current state of AFS in this complex population and explore opportunities for multidisciplinary collaboration.

Core Recommendations for Antifungal Stewardship: A Statement of the Mycoses Study Group Education and Research Consortium

In recent years, the global public health community has increasingly recognized the importance of antimicrobial stewardship (AMS) in the fight to improve outcomes, decrease costs, and curb increases in antimicrobial resistance around the world. However, the subject of antifungal stewardship (AFS) has received less attention. While the principles of AMS guidelines likely apply to stewarding of antifungal agents, there are additional considerations unique to AFS and the complex field of fungal infections that require specific recommendations. In this article, we review the literature on AMS best practices and discuss AFS through the lens of the global core elements of AMS. We offer recommendations for best practices in AFS based on a synthesis of this evidence by an interdisciplinary expert panel of members of the Mycoses Study Group Education and Research Consortium. We also discuss research directions in this rapidly evolving field. AFS is an emerging and important component of AMS, yet requires special considerations in certain areas such as expertise, education, interventions to optimize utilization, therapeutic drug monitoring, and data analysis and reporting.

Treatment of infections in cancer patients: an update from the neutropenia, infection and myelosuppression study group of the Multinational Association for Supportive Care in Cancer (MASCC)

INTRODUCTION

Patients with hematological and advanced solid malignancies have acquired immune dysfunction, often exacerbated by treatment, posing a significant risk for the development of infections. This review evaluates the utility of current clinical and treatment guidelines, in the setting of management of infections in cancer patients.

AREAS COVERED

These include causes of infection in cancer patients, management of patients with high-risk and low-risk febrile neutropenia, management of low-risk patients in an outpatient setting, the role of granulocyte colony-stimulating factor (G-CSF) in the prevention and treatment of neutropenia-related infections, management of lung infections in various clinical settings, and emerging challenges surrounding the risk of infection in cancer patients treated with novel treatments. The literature search was performed by accessing PubMed and other databases, focusing on published clinical trials of relevant anti-cancer agents and diseases, primarily covering the recent past, but also including several key studies published during the last decade and, somewhat earlier in a few cases.

EXPERT REVIEW

Notwithstanding the promise of gene therapy/gene editing in hematological malignancies and some types of solid cancers, innovations introduced in clinical practice include more discerning clinical management such as the generalized use of biosimilar formulations of G-CSF and the implementation of novel, innovative immunotherapies.

Urine Antigen Detection as an Aid to Diagnose Invasive Aspergillosis

Background

Establishing rapid diagnoses of invasive aspergillosis (IA) is a priority tests that detect galactomannan and β-d-glucan are available, but are technically cumbersome and rely on invasive sampling (blood or bronchoalveolar lavage).

Methods

We optimized a lateral flow dipstick assay using the galactofuranose-specific monoclonal antibody (mAb476), which recognizes urine antigens after Aspergillus fumigatus pulmonary infection in animals. Urine samples were obtained from a cohort of 78 subjects undergoing evaluation for suspected invasive fungal infections, and stored frozen until testing. Urine was processed by centrifugation through desalting columns and exposed to dipsticks. Reviewers blinded to clinical diagnoses graded results. Western blots were performed on urine samples from 2 subjects to characterize mAb476-reactive antigens.

Results

Per-patient sensitivity and specificity for diagnosis of proven or probable IA in the overall cohort was 80% (95% confidence interval [CI], 61.4%-92.3%) and 92% (95% CI, 74%-99%), respectively. In the subgroup with cancer, sensitivity was 89.5% (95% CI, 66.7%-98.7%) and specificity was 90.9% (95% CI, 58.7%-99.8%); among all others, sensitivity and specificity were 63.6% (95% CI, 30.8%-89.1%) and 92.9% (95% CI, 66.1%-99.8%), respectively. Eliminating lung transplant recipients with airway disease increased sensitivity in the noncancer cohort (85.7% [95% CI, 42.1%-99.6%]). Semiquantitative urine assay results correlated with serum galactomannan indices. Western blots demonstrated mAb476-reactive antigens in urine from cases, ranging between 26 kDa and 35 kDa in size.

Conclusions

Urine testing using mAb476 may be used as an aid to diagnose IA in high-risk patients.

Invasive aspergillosis manifesting as retinal necrosis in a patient treated with ruxolitinib

A 30 year-old man with acute myeloblastic leukaemia and secondary myelodysplastic syndrome developed graft-versus-host disease. The patient was treated with ruxolitinib. After being treated for 3 months with ruxolitinib, an inhibitor of Janus kinase, he developed Aspergillus retinal necrosis resistant to common treatment. Treatment with Janus kinase inhibitors may lead to an increased incidence of opportunistic infections. Janus kinase inhibitor administration may result in poor treatment efficacy.

Urine Antigen Detection as an Aid to Diagnose Invasive Aspergillosis

Background

Establishing rapid diagnoses of invasive aspergillosis (IA) is a priority tests that detect galactomannan and β-d-glucan are available, but are technically cumbersome and rely on invasive sampling (blood or bronchoalveolar lavage).

Methods

We optimized a lateral flow dipstick assay using the galactofuranose-specific monoclonal antibody (mAb476), which recognizes urine antigens after Aspergillus fumigatus pulmonary infection in animals. Urine samples were obtained from a cohort of 78 subjects undergoing evaluation for suspected invasive fungal infections, and stored frozen until testing. Urine was processed by centrifugation through desalting columns and exposed to dipsticks. Reviewers blinded to clinical diagnoses graded results. Western blots were performed on urine samples from 2 subjects to characterize mAb476-reactive antigens.

Results

Per-patient sensitivity and specificity for diagnosis of proven or probable IA in the overall cohort was 80% (95% confidence interval [CI], 61.4%-92.3%) and 92% (95% CI, 74%-99%), respectively. In the subgroup with cancer, sensitivity was 89.5% (95% CI, 66.7%-98.7%) and specificity was 90.9% (95% CI, 58.7%-99.8%); among all others, sensitivity and specificity were 63.6% (95% CI, 30.8%-89.1%) and 92.9% (95% CI, 66.1%-99.8%), respectively. Eliminating lung transplant recipients with airway disease increased sensitivity in the noncancer cohort (85.7% [95% CI, 42.1%-99.6%]). Semiquantitative urine assay results correlated with serum galactomannan indices. Western blots demonstrated mAb476-reactive antigens in urine from cases, ranging between 26 kDa and 35 kDa in size.

Conclusions

Urine testing using mAb476 may be used as an aid to diagnose IA in high-risk patients.

Prospective evaluation of a combination of fungal biomarkers for the diagnosis of invasive fungal disease in high-risk haematology patients

We prospectively evaluated a combination of fungal biomarkers in adult haematology patients with focus on their clinical utility at different time points during the course of infection. In total, 135 patients were monitored once to twice weekly for serum (1-3)-ß-d-glucan (BG), galactomannan (GM), bis-methyl-gliotoxin and urinary d-arabinitol/l-arabinitol ratio. In all, 13 cases with proven or probable invasive fungal disease (IFD) were identified. The sensitivity of BG and GM at the time of diagnosis (TOD) was low, but within 2 weeks from the TOD the sensitivity of BG was 92%. BG >800 pg/mL was highly specific for IFD. At a pre-test probability of 12%, both BG and GM had negative predictive values (NPV) >0.9 but low positive predictive values (PPV). In a subgroup analysis of patients with clinically suspected IFD (pre-test probability of 35%), the NPV was lower, but the PPV for BG was 0.86 at cut-off 160 pg/mL. Among IFD patients, 91% had patterns of consecutively positive and increasing BG levels. Bis-methyl-gliotoxin was undetectable in 15 patients with proven, probable and possible IA. To conclude, BG was the superior fungal marker for IFD diagnosis. Quantification above the limit of detection and graphical evaluation of the pattern of dynamics are warranted in the interpretation of BG results.

Serum galactomannan for diagnosing invasive aspergillosis in pediatric patients: A meta-analysis

BACKGROUND

The serum galactomannan (GM) assay is used to diagnose invasive aspergillosis (IA). We conducted a systematic review and analysis to estimate the overall accuracy of the serum GM test for diagnosing pediatric IA.

METHOD

A systematic literature review was conducted of all relevant studies published in PubMed and EMbase databases up to March 10, 2017. We selected and assessed articles that reported diagnostic data related to serum GM for diagnosis of pediatric IA. Pooled diagnostic odds ratios (DORs) and summary receiver operating characteristics (SROCs) were constructed with a cutoff value of 0.5. Additionally, pooled sensitivity (SEN), specificity (SPE), and positive and negative likelihood ratios (PLR and NLR, respectively) were estimated for summarizing overall test performance.

RESULTS

Seventeen studies were included in this systematic review. The total number of patients (age range 0-21 years old) was 1768, with 178 that had proven or probable IA. The pooled serum GM assay results, with a cutoff value of 0.5 for proven or probable IA, were DOR: 41.16 (95% confidence interval (CI) 21.48-78.86), SEN: 0.85 (95% CI 0.72-0.93), SPE: 0.88 (95% CI 0.80-0.93), PLR: 6.92 (95% CI 4.40-10.88), and NLR: 0.17 (95% CI 0.09-0.32). The SROC was 0.93.

CONCLUSION

Serum GM can be used to assist in diagnosis of proven or probable pediatric IA. However, serum GM test results should be interpreted in combination with clinical findings in pediatric IA cases, as the test results are not always sensitive or specific enough for pediatric IA.

Galactofuranose antigens, a target for diagnosis of fungal infections in humans

The use of biomarkers for the detection of fungal infections is of interest to complement histopathological and culture methods. Since the production of antibodies in immunocompromised patients is scarce, detection of a specific antigen could be effective for early diagnosis. D-Galactofuranose (Galf) is the antigenic epitope in glycoconjugates of several pathogenic fungi. Since Galf is not biosynthesized by mammals, it is an attractive candidate for diagnosis of infection. A monoclonal antibody that recognizes Galf is commercialized for detection of aspergillosis. The linkage of Galf in the natural glycans and the chemical structures of the synthesized Galf-containing oligosaccharides are described in this paper. The oligosaccharides could be used for the synthesis of artificial carbohydrate-based antigens, not enough exploited for diagnosis.

D-Galactofuranose (Galf) is the unit in polysaccharides and glycoconjugates of several pathogenic fungi that is recognized by the immune system. Since Galf is not synthesized by mammals, it is an attractive candidate for diagnosis of infection. Since the production of antibodies in immunocompromised patients is scarce, detection of a specific antigen could be effective for early diagnosis. An antibody that recognizes Galf is commercialized for the detection of aspergillosis. Chemically synthesized Galf-containing oligosaccharides, reviewed in this paper, could therefore be used for the synthesis of artificial carbohydrate-based antigens and in diagnosis.

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.

Nonspecific elevation of serum Aspergillus galactomannan antigen levels in patients with rheumatoid arthritis

BACKGROUND

Infections are an important cause of morbidity and mortality in patients with rheumatoid arthritis. Patients receiving immunosuppressive or anti-tumor necrosis factor (TNF) agents are vulnerable to fungal infections, including those derived from Aspergillus species. Detection of the Aspergillus galactomannan antigen in serum is useful for the early diagnosis of invasive aspergillosis in patients with hematological malignancies. However, its usefulness for detecting early invasive aspergillosis in rheumatoid arthritis patients remains unestablished.

METHODS

Galactomannan antigen levels were measured in 340 patients (311 female patients). For patients who exhibited galactomannan antigen levels ≥0.5 during the initial examination, a second examination was performed 3-6 months later. Conventional blood tests and chest radiography were also performed.

RESULTS

Elevated galactomannan antigen levels (≥0.5) were observed in 62 (18.2%) of 340 patients during the initial examination. A second examination was performed in 56 of 62 patients, 50 of whom exhibited elevated antigen levels. Elevated antigen levels were not associated with the use of any drug including anti-TNF agents. Serum galactomannan antigen levels were correlated with the albumin/globulin ratio (r=-0.19, p<0.001), γ-globulin (%; r=0.17, p=0.001), and hemoglobin concentration (r=-0.15, p=0.005). No patient was clinically diagnosed with invasive aspergillosis during the study period.

CONCLUSIONS

Serum galactomannan antigen levels are frequently elevated in a nonspecific manner in patients with rheumatoid arthritis.

Pneumonia in the neutropenic cancer patient

PURPOSE OF REVIEW

Pneumonia is the leading cause of death among neutropenic cancer patients, particularly those with acute leukaemia. Even with empiric therapy, case fatality rates of neutropenic pneumonias remain unacceptably high. However, recent advances in the management of neutropenic pneumonia offer hope for improved outcomes in the cancer setting. This review summarizes recent literature regarding the clinical presentation, microbiologic trends, diagnostic advances and therapeutic recommendations for cancer-related neutropenic pneumonia.

RECENT FINDINGS

Although neutropenic patients acquire pathogens both in community and nosocomial settings, patients' obligate healthcare exposures result in the frequent identification of multidrug-resistant bacterial organisms on conventional culture-based assessment of respiratory secretions. Modern molecular techniques, including expanded use of galactomannan testing, have further facilitated identification of fungal pathogens, allowing for aggressive interventions that appear to improve patient outcomes. Multiple interested societies have issued updated guidelines for antibiotic therapy of suspected neutropenic pneumonia. The benefit of antibiotic medications may be further enhanced by agents that promote host responses to infection.

SUMMARY

Neutropenic cancer patients have numerous potential causes for pulmonary infiltrates and clinical deterioration, with lower respiratory tract infections among the most deadly. Early clinical suspicion, diagnosis and intervention for neutropenic pneumonia provide cancer patients' best hope for survival.

Practice Guidelines for the Diagnosis and Management of Skin and Soft Tissue Infections: 2014 Update by the Infectious Diseases Society of America

A panel of national experts was convened by the Infectious Diseases Society of America (IDSA) to update the 2005 guidelines for the treatment of skin and soft tissue infections (SSTIs). The panel's recommendations were developed to be concordant with the recently published IDSA guidelines for the treatment of methicillin-resistant Staphylococcus aureus infections. The focus of this guideline is the diagnosis and appropriate treatment of diverse SSTIs ranging from minor superficial infections to life-threatening infections such as necrotizing fasciitis. In addition, because of an increasing number of immunocompromised hosts worldwide, the guideline addresses the wide array of SSTIs that occur in this population. These guidelines emphasize the importance of clinical skills in promptly diagnosing SSTIs, identifying the pathogen, and administering effective treatments in a timely fashion.

Current challenges in the microbiological diagnosis of invasive aspergillosis

The diagnosis of invasive aspergillosis is challenging because no sufficiently sensitive or specific tests have been developed to date. Infection can only be confirmed using histology, although this approach is unavailable in many patients. Therefore, diagnosis of invasive aspergillosis is based on a combination of the presence of host factors, radiological and clinical findings, and mycological criteria. In clinical practice, lack of optimal diagnostics often leads to empirical therapy and great cost and toxicity. Mycological criteria include the isolation of Aspergillus from clinical samples or the detection of biomarkers in fluids. Culture is cheap and easy and enables the identification of fungi and performance of antifungal susceptibility testing; however, it has low sensitivity and specificity. Non-culture-based diagnosis is based on the detection of fungal biomarkers such as galactomannan or (1 → 3)-β-D-glucan in normally sterile body fluids. These procedures enable faster and more sensitive and specific detection of Aspergillus; however, diagnostic accuracy is affected by the patient's underlying condition. Finally, while detection of Aspergillus DNA is promising, the lack of standardization limits its inclusion as a mycological criterion for the definition of probable invasive aspergillosis. New diagnostic procedures based on lateral flow technology are also promising but need further evaluation. In the present review, we discuss current culture-based and non-culture-based procedures for the microbiological diagnosis of invasive aspergillosis.

Reduction in false-positive Aspergillus serum galactomannan enzyme immunoassay results associated with use of piperacillin-tazobactam in the United States

Piperacillin-tazobactam (PTZ) is known to cause false-positive results in the Platelia Aspergillus enzyme-linked immunoassay (EIA), due to contamination with galactomannan (GM). We tested 32 lots of PTZ and 27 serum specimens from patients receiving PTZ. GM was not detected in the lots of PTZ; one serum specimen (3.7%) was positive. PTZ formulations commonly used in the United States today appear to be a rare cause for false-positive GM results.

Pulmonary fungal infections

This review details some of the advances that have been made in the recent decade in the diagnosis, treatment and epidemiology of pulmonary fungal infections. These advances have occurred because of increasing knowledge regarding the fungal genome, better understanding of the structures of the fungal cell wall and cell membrane and the use of molecular epidemiological techniques. The clinical implications of these advances are more rapid diagnosis and more effective and less toxic antifungal agents. For example, the diagnosis of invasive pulmonary aspergillosis, as well as histoplasmosis and blastomycosis, has improved with the use of easily performed antigen detection systems in serum and bronchoalveolar lavage fluid. Treatment of angioinvasive moulds has improved with the introduction of the new azoles, voriconazole and posaconazole that have broad antifungal activity. Amphotericin B is less frequently used, and when used is often given as lipid formulation to decrease toxicity. The newest agents, the echinocandins, are especially safe as they interfere with the metabolism of the fungal cell wall, a structure not shared with humans cells. Epidemiological advances include the description of the emergence of Cryptococcus gattii in North America and the increase in pulmonary mucormycosis and pneumonia due to Fusarium and Scedosporium species in transplant recipients and patients with haematological malignancies. The emergence of azole resistance among Aspergillus species is especially worrisome and is likely related to increased azole use for treatment of patients, but also to agricultural use of azoles as fungicides in certain countries.

Systematic review and meta-analysis of detecting galactomannan in bronchoalveolar lavage fluid for diagnosing invasive aspergillosis

BACKGROUND

Bronchoalveolar lavage (BAL) galactomannan (GM) assay has been used for diagnosing invasive aspergillosis (IA). We aimed to derive a definitive estimate of the overall accuracy of BAL-GM for diagnosing IA.

METHODS AND RESULTS

We undertook a systematic review of thirty diagnostic studies that evaluated the BAL-GM assay for diagnosing IA. PubMed and CBM (China Biological Medicine Database) databases were searched for relevant studies published in all languages up until Feb 2012. The pooled diagnostic odds ratio (DOR) and summary receiver operating characteristic (SROC) were constructed for each cutoff value. Additionally, pooled sensitivity (SEN), specificity (SPE), and positive and negative likelihood ratios (PLR and NLR, respectively) were calculated for summarizing overall test performance. Thirty studies were included in this meta-analysis. The summary estimates of pooled DOR, SEN, SPE, PLR, and NLR of the BAL-GM assay (cutoff value 0.5) for proven or probable IA were 52.7 (95% confidence interval (CI) 31.8-87.3), 0.87 (95% CI 0.79-0.92), 0.89 (95% CI 0.85-0.92), 8.0 (95% CI 5.7-11.1) and 0.15 (95% CI 0.10-0.23) respectively. The SROC was 0.94 (95% CI 0.92-0.96). Compared with cutoff value of 0.5, it has higher DOR, SPE and PLR, and similar SEN and NLR with cutoff value of 1.0, which indicated the optimal cutoff value might be 1.0. Compared with BAL-GM, serum GM has a lower SEN and higher SPE, while PCR displays a lower SEN and a similar SPE.

CONCLUSION

With the optimal cutoff value of 1.0, the BAL-GM assay has higher SEN compared to PCR and serum GM test. It is a useful adjunct in the diagnosis of proven and probable IA.

Bis(methyl)gliotoxin proves to be a more stable and reliable marker for invasive aspergillosis than gliotoxin and suitable for use in diagnosis

The virulence factor gliotoxin (GT) and its inactive derivative, bis(methylthio)gliotoxin (bmGT), are produced by pathogens of the genus Aspergillus. Here we report the detection of GT and bmGT in serum of humans at risk of invasive aspergillosis (IA) as well as in cultures of fungal isolates derived from patients with proven infection with A. fumigatus. Although both compounds are readily recoverable from spiked human serum or plasma, only bmGT is retained in whole blood, indicating that bmGT may be the better marker for in vivo detection. Accordingly, bmGT was found more frequently than GT in samples from patients at risk of IA and incultures of clinical isolates of A. fumigatus. In some cases, bmGT was detected before mycologic evidence ofinfection was gained. Importantly, neither GT nor bmGT was found in serum from healthy donors or from neutropenic patients without any sign of infection. Thus, bmGT presence might provide a more reliable indicator of A. fumigatus infections than GT. Due to its simplicity and sensitivity, a diagnostic technology based on this test could be easily adopted in clinical laboratories to help in the diagnosis of this often fatal fungal infection.

Galactomannan antigenemia after infusion of gluconate-containing Plasma-Lyte

We demonstrated that sodium gluconate was the factor causing false-positive galactomannan (GM) antigenemia of Plasma-Lyte hydration solution. Infusion of sodium gluconate-containing solution but not gluconate-free Plasma-Lyte resulted in positive serum GM antigenemia. Serum GM concentrations also correlated with the volume and in vitro concentrations of GM within gluconate-containing solutions of infused Plasma-Lyte.

Epidemiology and treatment approaches in management of invasive fungal infections

Over the past 20 years, the number of invasive fungal infections has continued to persist, due primarily to the increased numbers of patients subjected to severe immunosuppression. Despite the development of more active, less toxic antifungal agents and the standard use of antifungal prophylaxis, invasive fungal infections (especially invasive mold infections) continue to be a significant factor in hematopoietic cell and solid organ transplantation outcomes, resulting in high mortality rates. Since the use of fluconazole as standard prophylaxis in the hematopoietic cell transplantation setting, invasive candidiasis has come under control, but no mold-active antifungal agent (except for posaconazole in the setting of acute myelogenous leukemia and myelodysplastic syndrome) has been shown to improve the survival rate over fluconazole. With the advent of new azole and echinocandin agents, we have seen the emergence of more azole-resistant and echinocandin-resistant fungi. The recent increase in zygomycosis seen in the hematopoietic cell transplantation setting may be due to the increased use of voriconazole. This has implications for the empiric approach to pulmonary invasive mold infections when zygomycosis cannot be ruled out. It is imperative that an amphotericin B product, an antifungal that has never developed resistance in over 50 years, be initiated. The clinical presentations of invasive mold infections and invasive candidiasis can be nonspecific and the diagnostic tests insensitive, so a high index of suspicion and immediate initiation of empiric therapy is required. Unfortunately, our currently available serologic tests do not predict infection ahead of disease, and, therefore cannot be used to initiate “preemptive” therapy. Also, the Aspergillus galactomannan test gives a false negative result in patients receiving antimold prophylaxis, ie, virtually all of our patients with hematologic malignancy and hematopoietic cell transplant recipients. We may eventually be able to select patients at highest risk for invasive fungal infections for prophylaxis by genetic testing. However, with our current armamentarium of antifungal agents and widespread use of prophylaxis in high-risk groups (hematologic malignancy, hematopoietic cell transplantation), we continue to see high incidence and mortality rates, and our future hope lies in reversing the immunosuppression or augmenting the immune system of these severely immunocompromised hosts by developing and utilizing immunotherapy, immunoprophylaxis, and vaccines.

Approaches to the early treatment of invasive fungal infection

Invasive fungal infections account for significant morbidity and mortality in the seriously immunocompromised host, especially those suffering from hematologic malignancies and the recipients of hematopoietic cell transplant. One of the reasons for the continuing high mortality rates due to invasive fungal infection is the delay in administering appropriate therapy. As preemptive antifungal therapy is not feasible for lack of a predictive test, early empiric therapy is currently the only approach likely to result in improvement in survival. Here, we present our approach to both invasive candidiasis and invasive mold infection. Therapy should be initiated at the first signs and symptoms of disease, utilizing knowledge of local fungal epidemiology, the patient's recent antifungal agent exposure, and the diagnostic tests immediately available, to select an appropriate antifungal agent most likely to be effective against the suspected fungal species.

[Mycoserology--did we move on? Aspergillus]

Diseases caused by Aspergillus spp. are difficult to diagnose and thus require supplementary serological assays. This is the result of a selective review of the relevant literature with special regard to recent guidelines. In addition to conventional diagnostic tools (radiology, microscopy, culture) the measurement of the following serological markers is recommended, depending on the clinical type of aspergillosis: Invasive and chronic necrotising aspergillosis: Aspergillus-galactomannan antigen. Test format: EIA using the rat MAb EB-A2. Cut-off 0.5 (index). Monitoring of high risk patients: Twice weekly. Aspergillus-IgG (test format EIA) as confirmatory assay after recovery of the leukocyte function under therapy. Aspergilloma: Aspergillus IgG. Test format: EIA. Allergical aspergillosis: Aspergillus IgE. Test format: RAST. Galactomannan antigen detection rates high in the diagnosis of invasive aspergillosis. The evaluation of Aspergillus nucleic acid amplification assays is pending.

Current aspects of invasive candidiasis and aspergillosis in adult intensive care patients

Sepsis is a leading cause of death in the intensive care unit (ICU), with Candida spp. in the forefront among the important pathogens. As recent studies have shown, survival outcome is strongly influenced by adequate antifungal therapy at an early stage that is often delayed by the time lag associated with microbiological diagnosis. Risk factor-based prediction models have a high negative predictive value, but positive prediction of candidaemia in the individual patient remains elusive. New antigen- or DNA-based methods for early diagnosis still await clinical validation. Their routine use is hampered by methodological issues. Species distribution of invasive Candida isolates in the ICU appears to be influenced primarily by age, previous hospitalisation and colonising species. In the context of the importance of adequate first-line treatment, recent guidelines favour the use of echinocandins in critically ill patients with symptoms evoking high suspicion of invasive candidiasis. This is supported by robust clinical trial data, a few interactions and low toxicity. Fluconazole is characterised by reduced activity against some important Candida species, elevated rates of persistent infection seen in comparative trials. Amphotericin B deoxycholate should be considered obsolete in ICU patients because of its high toxicity. Invasive aspergillosis (IA) is a rare devastating infection in the general ICU population, but some centres have reported elevated incidences and underdiagnosis as determined in autopsy-controlled studies. Treatment with mould-active agents such as voriconazole must be initiated early in patients with suspected IA.

Trends in the postmortem diagnosis of opportunistic invasive fungal infections in patients with AIDS: a retrospective study of 1,630 autopsies performed between 1984 and 2002

We retrospectively evaluated autopsy-proven invasive fungal infections (IFIs) in patients with AIDS who died between 1984 and 2002. IFIs were identified in 297 (18.2%) of 1,630 autopsies. Their prevalence significantly decreased over time (from 25.0% in 1984-1988 to 15% in 1998-2002; P = .004), mainly owing to a significant decrease in pneumocystosis (P = .017) and cryptococcosis (P = .003), whereas the prevalence of aspergillosis and histoplasmosis remained relatively stable and of candidiasis and zygomycosis tended to increase in the last years (P = .028 and P = .042, respectively). IFIs were suspected or confirmed during life in only 46.8% of the cases; this proportion did not vary significantly over time (P = .320). The infections contributed to the deaths of 103 patients (34.7%), and their global impact on mortality was 6.3%. Of fatal cases, 38 (36.9%) were characterized by missed antemortem diagnoses, 17 (45%) of which met Goldman criteria for class I errors. The epidemiology of IFIs in patients with AIDS is evolving and not completely mirrored by clinical diagnoses or current diagnostic methods. Our results confirm the valuable role of autopsy data, even with highly effective therapies and advanced technologies.

Invasive aspergillosis: diagnosis, prophylaxis and treatment

PURPOSE OF REVIEW

Invasive aspergillosis is a common cause of morbidity and mortality in hematopoietic stem cells transplant recipients. Owing to its intrinsic high mortality rate, early diagnosis and treatment are critical. This review will therefore address the most important recent advances in diagnosing, preventing and treating invasive aspergillosis in hematopoietic stem cells transplant.

RECENT FINDINGS

The present review will focus on therapeutic and prophylactic aspects, with particular regard to clinical use of drugs other than voriconazole (which has a well known and consolidated role for first-line therapy), combination therapy and prophylactic regimens, particularly with posaconazole. This review will also briefly deal with the clinical role of diagnostic tests such as the detection of galactomannan in body fluids other than blood, beta-D-glucan in serum and fungal DNA by PCR in body fluids.

SUMMARY

Galactomannan antigen detection is a rather reliable diagnostic test for invasive aspergillosis, particularly when a lower threshold of sensitivity is used. PCR is still to be validated. Liposomal amphotericin B at 3 mg/kg per day showed a similar efficacy in invasive aspergillosis as reported for voriconazole. Therapeutic drug monitoring of Aspergillus-active azoles should be implemented whenever possible in order to maximize the antifungal effect and minimize toxicity. Posaconazole showed to be active in prophylaxis, though its effectiveness in the global patient population is still controversial.

Impact of PCR-based diagnosis of invasive pulmonary aspergillosis on clinical outcome

The mortality rate of 60-90% in invasive pulmonary aspergillosis (IPA) is partly explained by diagnostic delay due to the limitation of current diagnostic tests. We assessed the influence of Aspergillus species (ASP) DNA detection by PCR from bronchoalveolar lavage (BAL) fluid, a new tool for diagnosing IPA, on the outcome of this disease in immune-compromised patients. The study population comprised 107 consecutive patients with hematological malignancies from a single medical center with IPA diagnosed between 1998 and 2005. Clinical variables and mortality rates were compared between two groups diagnosed according to traditional criteria without and with PCR-based ASP DNA detection in BAL fluid. The overall mortality rate during the study period was 38.3%. The addition of PCR to the diagnostic criteria shifted 31 patients from possible to probable IPA. Patients diagnosed with probable IPA according to traditional microbiological methods had significantly higher mortality rates compared to their counterparts who had in addition a PCR-based diagnosis (80 vs 35.6%, P=0.003). This study demonstrates that PCR-based ASP DNA detection for a diagnosis of IPA from BAL fluid has a significant effect on the outcome of patients with IPA, probably related to earlier diagnosis.

Galactomannan detection as a tool for the diagnosis and management of cardiac aspergillosis in 2 immunocompetent patients

Serum galactomannan antigen detection was used for the diagnosis and follow-up of cardiac aspergillosis after surgery in 2 nonneutropenic patients. The galactomannan index, developed in response to surgical and antifungal therapies, could prove to be a valuable method for the diagnosis and follow-up of fungal infections in such patients.

Significant alterations in the epidemiology and treatment outcome of invasive fungal infections in patients with hematological malignancies

Invasive fungal infections (IFI) remain a leading cause of morbidity and mortality in immunocompromised patients. This retrospective single-center study analyzed incidence, treatment and outcome of invasive fungal infections in 1,095 patients with hematological malignancies receiving either cytoreductive chemotherapy or autologous or allogeneic hematopoietic stem cell transplantation at our institution between 1995 and 2004. IFI occurred in 167/1,095 (15%) patients with a significant increase over time (12.7% between 1995 and 2000 vs. 18.1% in the later IFI cohort, P = 0.0134). Fifty-four (32%) patients had proven, 70 (42%) patients had probable, and 43 (26%) patients suffered from possible IFI according to EORTC/MSG criteria. In 108/124 (87%) cases with proven or probable IFI, moulds were the causative pathogens. Both, Aspergillus fumigatus (n = 46) and Aspergillus terreus (n = 41) were predominant. Yeast infections (Candida spp.) were documented in 16/124 (10%) cases with proven or probable IFI. Median overall survival of the entire IFI cohort was 7 (3-17) months. Overall survival was significantly better in patients with probable or possible IFI (37 and 38%, respectively) compared with patients with proven IFI (28%, P = 0.019). In 35% of patients, IFI was the principal cause of death with a significant decrease over time (44% in time cohort 1995-2000 vs. 28% in the later IFI cohort, P = 0.018) accompanied by an increased use of novel antifungals. By multivariate analysis, only proven IFI was significantly predictive for death (HR 1.7, P = 0.018). A significant decrease in fungus-related deaths was observed despite a significant increase of IFI over time, probably due to improved diagnostic and therapeutic approaches.

Performance characteristics of the platelia Aspergillus enzyme immunoassay for detection of Aspergillus galactomannan antigen in bronchoalveolar lavage fluid

We have evaluated the Platelia Aspergillus enzyme immunoassay for detection of galactomannan in bronchoalveolar lavage (BAL) specimens in solid organ transplant patients with aspergillosis. The precision and reproducibility in serum or BAL to which galactomannan was added were similar. Sensitivity was 81.8% in patients with aspergillosis, and specificity was 95.8% in lung transplant patients who underwent BAL for surveillance for infection or rejection. Among transplant controls, positive results were more common in patients (i) who underwent diagnostic BAL performed for evaluation of symptoms or chest computed tomographic abnormalities, (ii) who had undergone lung transplantation, or (iii) who were colonized with Aspergillus. Galactomannan testing in BAL is useful for diagnosis of aspergillosis in transplant patients. The significance of positive results in patients without confirmed aspergillosis requires further evaluation.