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

Diagnostic accuracy of galactomannan and lateral flow assay in invasive aspergillosis: A diagnostic meta-analysis

Background

Efficient diagnosis of patients at high risk for invasive aspergillosis (IA) improves the outcome of the disease. Lateral flow assay (LFA) is a novel technology and assessing its diagnostic accuracy is of great significance in the clinical management of IA.

Methods

A meta-analysis using case-control studies was performed to assess the diagnostic performance of LFA alone or galactomannan (GM) combined with LFA (GM-LFA) as screening tests for IA. The sensitivity, specificity, and summary receiver operating characteristic curves were constructed.

Results

Nineteen studies with 2838 patients were included. The pooled effect sizes for different indicators included: sensitivity (77 % for LFA and 75 % for GM-LFA), specificity (88 % for LFA and 87 % for GM-LFA), positive likelihood ratio (6.65 for LFA and 12.02 for GM-LFA), negative likelihood ratio (0.26 for LFA and 0.27 for GM-LFA), and the diagnostic odds ratio (25.81 for LFA and 44.87 for GM-LFA). The area under the curve was 0.91 for LFA and 0.94 for GM-LFA with a cut-off value ≥ 0.5.

Conclusion

The present meta-analysis suggested that LFA or GM-LFA at an optical density index (ODI) cutoff of ≥0.5 was a useful diagnostic tool for IA in patients. The results showed no significant differences in the accuracy of LFA alone and GM-LFA in diagnosing IA. In the clinical diagnosis and treatment of IA, LFA can be recommended if timely results are needed.

Is there still a place for serum galactomannan in the diagnosis of invasive aspergillosis in children at high risk and under antifungal prophylaxis?

BACKGROUND

The performance of serum galactomannan (GM) for the diagnosis of invasive aspergillosis (IA) has been studied mainly in adults. Paediatric data are scarce and based on small and heterogeneous cohorts.

OBJECTIVE

To evaluate the performance of serum GM for the diagnosis of IA in a paediatric oncologic population at high risk of IA and to clarify the impact of antifungal prophylaxis on this test.

METHODS

We performed a retrospective study from January 2014 to December 2020 in the paediatric oncologic haematologic department of the University Hospital of Bordeaux. The diagnosis of IA was made using the recommendations of the EORTC and the MSGERC.

RESULTS

Among the 329 periods at high risk of IA in 222 patients, the prevalence of IA was 1.8% (3 proven and 3 probable IA). In the total population, the sensitivity, and the positive predictive value (PPV) were respectively 50% and 17.6%. Under antifungal prophylaxis, the sensitivity and PPV dropped, respectively, to 33.3% and 14.3%. In this group, the post-test probability of IA was 2% for a negative serum GM and only 14%.

CONCLUSION

In this large cohort of children at high risk of IA, the incidence of IA is low and the diagnostic performance of GM is poor, especially in the case of mould-active prophylaxis. Screening should be targeted rather than systematic and should be reserved for patients at highest risk for IA without mould-active prophylaxis. Combination with other tests such as Aspergillus PCR would increase the accuracy of GM in screening setting.

The Use of Galactomannan Antigen Assays for the Diagnosis of Invasive Pulmonary Aspergillosis in the Hematological Patient: A Systematic Review and Meta-Analysis

The optimal cut-off value of the optical density index of the galactomannan antigen assays (GM) for diagnosing invasive pulmonary aspergillosis in hematological patients is a disputed topic. This article conducts a systematic review with a meta-analysis to establish which optical density index (ODI) cut-off value should be implemented into clinical practice. Pubmed, Embase and Cochrane databases were searched (N = 27). The pooled data, using a generalized linear mixed model with binomial distribution, resulted in an overall serum sensitivity of 0.76 and a specificity of 0.92. For serum ODI 0.5 there was a pooled sensitivity of 0.92 and a specificity of 0.84. The pooled data of all broncho-alveolar lavage (BAL) studies resulted in an overall sensitivity of 0.80 and a specificity of 0.95. For BAL ODI 0.5, there was a pooled sensitivity of 0.75 and a specificity of 0.88. For the BAL ODI 1.0 pooling, the studies resulted in a sensitivity of 0.75 and a specificity of 0.96. Serum ODI of 0.5 and BAL ODI of 1.0 are the most suitable cut-offs for clinical practice. However, our study affirms that the evidence for the use of GM in clinical practice for the hematological malignancy patient is currently insufficient and more research is needed to determine the diagnostic value of GM.

Updates in Laboratory Identification of Invasive Fungal Infection in Neonates

Invasive fungal infection (IFI) in immunocompromised neonates is significantly associated with high morbidity and mortality and has become the third most common infection in Neonatal Intensive Care Units. The early diagnosis of IFI for neonatal patients is difficult because of the lack of specific symptoms. The traditional blood culture remains the gold standard in clinical diagnosis for neonatal patients but it requires a long duration, which delays treatment initiation. Detections of fungal cell-wall components are developed for early diagnosis but the diagnostic accuracy in neonates needs to be improved. PCR-based laboratory methods, such as real-time PCR, droplet digital PCR, and the cationic conjugated polymer fluorescence resonance energy transfer (CCP-FRET) system, distinguish the infected fungal species by their specific nucleic acids and show a high sensitivity and specificity. Particularly, the CCP-FRET system, which contains a cationic conjugated polymer (CCP) fluorescent probe and pathogen-specific DNA labeled with fluorescent dyes, could identify multiple infections simultaneously. In the CCP-FRET system, the CCP and fungal DNA fragments can self-assemble into a complex with an electrostatic interaction and the CCP triggers the FRET effect under ultraviolet light to make the infection visible. Here, we summarize the recent laboratory methods for neonatal IFI identification and provide a new perspective for early clinical fungal diagnosis.

The Role of Serum Galactomannan Assay as a Potential Surrogate Biomarker for Fungal Microinvasion in Allergic Fungal Rhinosinusitis

We conducted this study to determine if serum galactomannan (GM) can be used as a marker to implicate the invasiveness of allergic fungal rhinosinusitis (AFRS), and correlate this value with the aggressiveness of disease documented via computed tomography (CT). All paranasal CT scans done for AFRS patients prospectively over a five-year period (2015-2019) were included. An indigenous 20-point score was used to document the extent of bone erosion seen on CT, wherein a higher score meant a greater extent of bone erosion. It was then correlated with serum GM scores. The median CT scores of galactomannan-positive (GM+) patients were compared with the median CT scores of galactomannan-negative (GM-) patients 3 using Mann-Whitney U test. The patients were divided into five groups based on the extent of disease-No bone erosion, erosion of only sinus wall/orbit, 3 erosion of orbit and skull base, erosion of only skull base and lateral extension of disease into infratemporal fossa (ITF). Subgroup analysis was conducted over mean GM values in these groups using ANOVA test. p-value < 0.05 was considered significant. Statistical analysis was performed using SPSS version 25.0. A total of 92 patients were included (56 males, 36 females). No statistically significant difference was found (p-value = 0.42) between the CT scores of galactomannan-positive (GM+) group and galactomannan-negative (GM-) group. The mean GM scores amongst the five sub-groups did not show a statistically significant difference. Serum galactomannan values correlate poorly with aggressiveness of disease quantified on non-contrast CT of paranasal sinuses.

Metagenomic next-generation sequencing for the diagnosis of pulmonary aspergillosis in non-neutropenic patients: a retrospective study

This study aimed to obtain further in-depth information on the value of metagenomic next-generation sequencing (mNGS) for diagnosing pulmonary aspergillosis in non-neutropenic patients. We did a retrospective study, in which 33 non-neutropenic patients were included, of which 12 were patients with pulmonary aspergillosis and 21 were diagnosed with non-pulmonary aspergillosis. Fungi and all other co-pathogens in bronchoalveolar lavage fluid (BALF) (27 cases), blood (6 cases), and/or pleural fluid (1 case) samples were analyzed using mNGS. One of the patients submitted both BALF and blood samples. We analyzed the clinical characteristics, laboratory tests, and radiologic features of pulmonary aspergillosis patients and compared the diagnostic accuracy, including sensitivity, specificity, positive predictive value, and negative predictive value of mNGS with conventional etiological methods and serum (1,3)-β-D-glucan. We also explored the efficacy of mNGS in detecting mixed infections and co-pathogens. We further reviewed modifications of antimicrobial therapy for patients with pulmonary aspergillosis according to the mNGS results. Finally, we compared the detection of Aspergillus in BALF and blood samples from three patients using mNGS. In non-neutropenic patients, immunocompromised conditions of non-pulmonary aspergillosis were far less prevalent than in patients with pulmonary aspergillosis. More patients with pulmonary aspergillosis received long-term systemic corticosteroids (50% vs. 14.3%, p < 0.05). Additionally, mNGS managed to reach a sensitivity of 91.7% for diagnosing pulmonary aspergillosis, which was significantly higher than that of conventional etiological methods (33.3%) and serum (1,3)-β-D-glucan (33.3%). In addition, mNGS showed superior performance in discovering co-pathogens (84.6%) of pulmonary aspergillosis; bacteria, bacteria-fungi, and bacteria-PJP-virus were most commonly observed in non-neutropenic patients. Moreover, mNGS results can help guide effective treatments. According to the mNGS results, antimicrobial therapy was altered in 91.7% of patients with pulmonary aspergillosis. The diagnosis of Aspergillus detected in blood samples, which can be used as a supplement to BALF samples, seemed to show a higher specificity than that in BALF samples. mNGS is a useful and effective method for the diagnosis of pulmonary aspergillosis in non-neutropenic patients, detection of co-pathogens, and adjustment of antimicrobial treatment.

Antifungal Therapy in Pediatric Acute Lymphoblastic Leukemia: A Single-center Experience

INTRODUCTION

Invasive fungal infections (IFIs) are significant causes of morbidity and mortality in leukemia patients. This study investigated antifungal treatment and prophylaxis features according to leukemia risk groups and treatment phases in pediatric acute lymphoblastic leukemia (ALL) patients who received Berlin-Frankfurt-Munster-based protocols.

MATERIALS AND METHODS

We retrospectively examined ALL patients' data between the ages of 1 and 18 and treated them with Berlin-Frankfurt-Munster-ALL protocols between June 2013 and December 2016.

RESULTS

A total of 446 febrile neutropenic attacks in 85 children were evaluated. Seventy-two patients received antifungals in 151 infection attacks, while 13 patients did not receive any antifungal treatment during chemotherapy. Empirical, preemptive, or proven treatments were given to 74.8%, 21.2%, and 4% of patients, respectively. The frequency of antifungal therapy increased linearly and significantly from the standard-risk group to the intermediate-risk (IR) group, high-risk (HR) group, and relapsed group. IR patients needed more antifungal therapy while receiving induction, whereas HR patients needed more throughout the induction and HR consolidation blocks than other phases. During induction, IR patients received antifungal therapy similar to HR patients' treatment in the induction and HR consolidation blocks.

CONCLUSIONS

Antifungal therapy requirements increased as the severity and intensity of chemotherapy increased for all leukemia risk groups. The requirement of antifungal therapy for IR patients receiving induction was similar to that of HR patients; further studies are needed to evaluate the potential advantages of using primary antifungal prophylaxis in IR patients.

Clinical, Laboratory, Radiological, Bronchoscopic, and Outcome Characteristics of Pulmonary Fungal Infection in Children in PICU in Central China: A Case Series

OBJECTIVE

Fungal infections are common in pediatric intensive care units (PICUs), but the monitoring methods are limited. This study analyzed the differences in clinical features, diagnosis, and treatment between PICU patients with and without fungal infection.

METHODS

This retrospective study analyzed PICU patients at the Maternal and Child Health Hospital of Hubei Province diagnosed with severe pneumonia between January 2015 and January 2020. The patients were divided into the fungal (F) and non-fungal (NF) infection groups. Levels of 1,3-beta-D-glucan (BDG) and galactomannan (GM) in serum and bronchoalveolar lavage fluid (BALF) were analyzed. Chest computed tomography (CT) images were reviewed.

RESULTS

A total of 357 patients were included. In the F group, fever, moist rales, coarse rales, shortness of breath, and sepsis were more common (all P < 0.05); PICU time, hospitalization duration, and BDG- and GM-positive rates in serum and BALF were all significantly higher than in the NF group (all P < 0.05). The BDG- and GM-positive rates in serum and BALF were higher in the F than in the NF group (all P < 0.05). The abnormal lymphocyte ratios in serum were higher in the F group (all P < 0.05). Wedge-shaped, patchy, streaky shadows and subpleural reticulation were higher in CT images of the F group (all P < 0.05). Tracheobronchial stenosis was more common in pulmonary fibroscopy results of the F group (P = 0.04).

CONCLUSION

PICU pneumonia patients with fungal infection have specific clinical and laboratory features compared with those without fungal infection, including higher rates of BALF, serum BDG, GM positivity and tracheobronchial stenosis.

The role of galactomannan test results in the diagnosis of pediatric invasive aspergillosis

BACKGROUND

Invasive aspergillosis (IA) is an important cause of morbidity and mortality in immunosuppressed children. Early detection of the infection can improve prognosis in this patient population.

OBJECTIVES

To investigate the utility of Aspergillus galactomannan antigen assay (GM-EIA) as a diagnostic tool for IA in at-risk paediatric patients.

PATIENTS/METHODS

For the study, 659 GM-EIA results from 59 patients diagnosed with IA and 3368 GM-EIA results from 351 subjects without evidence for IA (controls) were reviewed retrospectively. Three cut-off values (i.e. ≥0.5, ≥1, ≥1.5) were specified to determine GM-EIA positivity.

RESULTS

The median age was 6.3 years for boys and 14.5 years for girls. There was a significant difference between the girls and boys in terms of age (p < 0.01). For proven/probable/possible IA patients, sensitivity of 67.8% and specificity of 59.8% were detected when the ≥0.5 cut-off value was used for GM-EIA-positivity. The specificity increased to 80% at the cut-off of ≥1 and to 88% at the cut-off of ≥1.5. False positivity rates were 9.14, 3, and 1.45% at the ≥0.5, ≥1 and ≥1.5 cut-offs respectively. In the proven/probable IA group, sensitivity and negative predictive values were 86.9 and 97.2% at the ≥0.5 cut-off, 85.7 and 97.9%, at the ≥1 cut-off and 84.2 and 98.1% at ≥1.5 cut-off respectively. The positive likelihood ratio was 7.57 and the odds ratio was 42.67 at ≥1.5 cut-off.

CONCLUSION

The GM-EIA may be used for both screening and diagnostic purposes in paediatric patients using a cut-off value of ≥1.5 for GM-EIA positivity.

Challenges with Utilizing the 1,3-Beta-d-Glucan and Galactomannan Assays To Diagnose Invasive Mold Infections in Immunocompromised Children

Establishing the diagnosis of invasive mold infections (IMI) in immunocompromised children is challenging due to nonspecific clinical presentations and the limited sensitivity of traditional culture-based methods. Rapid non-culture-based diagnostics such as the 1,3-beta-d-glucan and galactomannan assays have emerged as promising adjuncts to conventional diagnostic tests in adults. Available data suggest that 1,3-beta-d-glucan has limited accuracy in the pediatric population and is not recommended to be used for the diagnosis of IMI in children. On the other hand, the diagnostic performance of the serum and bronchoalveolar lavage galactomannan in immunocompromised children is comparable to results observed in adults and can be used as a screening tool in children at high risk of developing invasive aspergillosis (IA) who are not receiving mold-active antifungal prophylaxis and as a diagnostic tool in symptomatic children suspected of having IA. Herein, we summarize the available evidence for the use of these rapid non-culture-based diagnostics in immunocompromised children. We also summarize potential causes of false positivity for the 1,3-beta-d-glucan and galactomannan assays.

Detecting serum galactomannan to diagnose acute invasive Aspergillus sinusitis: a meta-analysis

PURPOSE

The serum galactomannan test has been used for diagnosing acute invasive fungal sinusitis (AIFS), especially invasive Aspergillus. We aimed to assess the accuracy of the test to diagnose acute invasive Aspergillus sinusitis (AIAS).

METHODS

We searched all relevant articles published in PubMed, Embase, the Cochrane Library, and Web of Science databases up until September 14, 2020. The available data for serum galactomannan test to diagnose AIAS from selected studies were assessed. The diagnostic odds ratio (DOR), summary receiver operating characteristics (SROC), sensitivity, specificity, positive likelihood ratio (PLR), and negative likelihood ratio (NLR) were estimated. Additionally, we analysed four studies with a cut-off value of 0.5.

RESULTS

Five eligible articles were selected in this study. The total number of enrolled patients was 118, and 62 patients had confirmed AIAS. Among these 62 patients, the summary estimates of the serum galactomannan assay were as follows: DOR, 3.37 (95% confidence interval [CI]: 1.47-6.66); sensitivity, 0.63 (95% CI 0.50-0.74); specificity, 0.65 (95% CI 0.51-0.76); PLR, 1.83 (95% CI 1.21-2.74); NLR, 0.58 (95% CI 0.39-0.83). The SROC was 0.68.

CONCLUSION

In this current meta-analysis, the serum galactomannan test was classified as less accurate for purposes of diagnosing confirmed AIAS. These results suggest that the initial diagnosis of AIAS should not solely be dependent upon serum galactomannan test results. More studies of the test are needed in patients with AIAS to more accurately assess its diagnostic value.

Diagnostic Value of Galactomannan in Bronchoalveolar Lavage Fluid for Chronic Respiratory Disease with Pulmonary Aspergillosis

The objective of this study was to explore the diagnostic value of the bronchoalveolar lavage fluid galactomannan (BALF GM) test for chronic respiratory disease with pulmonary aspergillosis and to establish the optimal cutoff value. Samples from a total of 309 chronic respiratory disease patients seen at the respiratory medicine department of Peking University Shenzhen Hospital from September 2016 to September 2019 were analyzed. According to the diagnostic criteria, we divided the patients into a case group (n = 79, comprising 25 proven cases and 54 probable cases) and a control group (n = 230). Bronchoalveolar lavage fluid was collected, and the BALF GM test results were analyzed. A nonparametric rank sum test showed that the mean rank of the case group was 255.30, which was higher than that of the control group (120.55). The Z-value was -11.567 (P = 0.000), indicating that the general distributions of BALF GM differed between the two groups. A BALF GM cutoff value of 0.88 showed the highest diagnostic efficacy for pulmonary aspergillosis. The sensitivity, specificity, positive predictive value, and negative predictive value were 77.2%, 93%, 79.2%, and 92.2%, respectively. As the cutoff value increased, the specificity and sensitivity of the BALF GM test increased and decreased, respectively. The BALF GM test can be used confirm the diagnosis of patients with pulmonary aspergillosis and chronic respiratory disease. The optimum BALF GM cutoff value is 0.88.

Emerging Invasive Fungal Infections: Clinical Features and Controversies in Diagnosis and Treatment Processes

Background

The diagnosis and treatment of invasive fungal infection (IFI) are still challenging due to its complexity and non-specificity. This study was aimed to investigate the clinical features, diagnosis process, and outcomes of patients with emerging IFIs.

Methods

A retrospective review of emerging IFIs in adult patients at a university hospital in China was conducted; diagnoses were based on the criteria of EORTC/MSG 2008.

Results

145 IFI patients (pulmonary, intestinal and urinary) were enrolled in this study, including 80 proven (55.2%), 59 probable (40.7%), or 6 possible IFIs (4.1%). Among the 126 pulmonary IFIs, the positivity rate for sputum microscopy, sputum culture, and 1.3-ß-D-glucan (BG) test was 54.0%, 44.4%, and 37.3%, respectively. Among the 19 intestinal and urinary IFIs, routine examination of stool or urine and their culture were the main methods of detection. Positive results of 75 detected fungal strains from the samples showed that 30 cases were complicated with one or more bacterial infections. The average length of hospital stay of IFI patients was 14.0 (10.0, 20.0) days. The time from admission to antifungal therapy initiation (P<0.001), liver cirrhosis (P<0.001), hematological tumor (P<0.001), coinfection (P=0.019) and immune diseases (P=0.025) were independent predictors of prolonged hospitalization.

Conclusion

Delayed time was the primary predictor of prolonged hospitalization. This prediction is suggested to improve IFI diagnostic and therapeutic process of IFI to promote prognosis.