beta-D-glucan Assay Research Articles

360. The diagnostic sensitivity of beta-D-glucan assay in patients with chronic disseminated candidiasis

Abstract Background Chronic disseminated candidiasis (CDC) is a specific syndrome in patients with hematologic malignancies which usually occurs after the recovery of neutrophils due to previous chemotherapy. The beta-D-glucan (BDG) assay has been proposed as an adjunct test for diagnosing invasive fungal infection. However, data on BDG assay in patients with CDC are scare. We aimed to investigate the diagnostic sensitivity of BDG assay in patients with CDC. Methods All adult patients who were diagnosed as CDC in a tertiary hospital in Seoul, South Korea, from January 2017 to December 2019 and underwent BDG assay (Gold Mountain River Tech Development, Beijing, China) were retrospectively reviewed. CDC was defined by the demonstration of small, target-like abscesses in liver or spleen (bull’s-eye lesions) or in the brain at the time of neutrophil recovery after a prolonged phase of neutropenia. The values for BDG over 80 pg/mL was classified as positive. Results A total of 20 patients were enrolled. The median age was 51 years (Interquartile range 39 – 64). Of these, 13 patients had acute myeloid leukemia, 3 acute lymphoid leukemia, 2 myelodysplastic syndrome, and 1 aplastic anemia. Candida spp. were isolated in 6 patients; 3 were C. tropicalis, 2 C. glabrata, and 1 C. krusei. Of the 20 patients, 10 (50%) revealed positive BDG results. The median BDG value was 174 pg/dL (IQR 137–402). More CDC patients with previous candidemia had positive BDG assay than those without candidemia, but with no statistical significance (4/5 (80%) vs. 6/15 (40%), P = 0.30). In the 7 patients with BDG assay-positive CDC, for whom follow-up BDG results were available, the BDG remained high in 6 patients (86%) for more than 4 weeks after adequate antifungal therapy. All 4 patients who died had a positive BDG assay, and 3 of them showed an increasing trend of BDG values during treatment. Conclusion Negative BDG assay appears to be not useful to rule out CDC. BDG assay decreased slowly during the adequate treatment of CDC. Disclosures All Authors: No reported disclosures.

Prospective Evaluation of the Fungitell® (1→3) Beta-D-Glucan Assay as a Diagnostic Tool for Invasive Fungal Disease in Pediatric Allogeneic Hematopoietic Cell Transplantation: AReport from the Children's Oncology Group.

Invasive fungal disease (IFD) is a major source of morbidity and mortality for hematopoietic cell transplant (HCT) recipients. Non-invasive biomarkers, such as the beta-D-glucan assay, may improve the diagnosis of IFD. The objective was to define the utility of surveillance testing using Fungitell® beta-D-glucan (BDG) assay in children receiving antifungal prophylaxis in the immediate post-HCT period. Weekly surveillance blood testing with the Fungitell® BDG assay was performed during the early post-HCT period in the context of a randomized trial of children, adolescents, and young adults undergoing allogeneic HCT allocated to triazole or caspofungin prophylaxis. Positivity was defined at the manufacturer cutoff of 80 pg/ml. IFD was adjudicated using blinded central reviewers. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for the Fungitell® BDG assay for the outcome of proven or probable IFD. A total of 51 patients (out of 290 patients in the parent trial) contributed blood specimens. In total, 278 specimens were evaluated. Specificity was 80.8% (95% confidence interval [CI]: 75.6%-85.3%), and NPV was over 99% (95% CI: 86.8%-99.9%). However, there were no true positive results, resulting in sensitivity of 0% (95% CI: 0.0%-84.2%) and PPV of 0% (95% CI: 0.0%-6.7%). Fungitell® BDG screening is of limited utility in diagnosing IFD in the post-HCT period, mainly due to high false-positive rates. Fungitell® BDG surveillance testing should not be performed in children during the early post-HCT period while receiving antifungal prophylaxis as the pretest probability for IFD is low.

Evaluation of (1-3)-Beta-D glucan Assay for Diagnosis of Invasive Fungal Infections

Evaluation of (1-3)-Beta-D glucan Assay for Diagnosis of Invasive Fungal Infections

Clinical Profile of Non-neutropenic Patients with Invasive Candidiasis: A Retrospective Study in a Tertiary Care Center.

Introduction: Invasive candidiasis (IC) is a major cause of morbidity and mortality in critically ill patients in the intensive care unit (ICU). In this study, we aim to analyze the clinical profile, species distribution, and susceptibility pattern of patients with IC.Methods: Case records of non-neutropenic patients ≥18 years of age with IC between January 2016 and June 2019 at a tertiary care referral hospital were analyzed. IC was defined as either candidemia or isolation of Candida species from a sterile site (such as CSF; ascitic, pleural, or pericardial fluid; or pus or tissue from an intraoperative sample) in a patient with clinical signs and symptoms of infection.Results: A total of 114 patients were analyzed, out of which 105 (92.1%) patients had bloodstream infection (BSI) due to Candida and 9 (7.9%) had IC identified from a sterile site. Central line-associated blood stream infection (27 patients, 23.6%) and a gastrointestinal source (30 patients, 26.3%) were the most common presumed sources for candidemia. The commonest species was Candida tropicalis 42 (36.8%), followed by Candida glabrata 20 (17.5%). Serum beta-D-glucan (BDG) was done only in 32 patients of the 114 (35.3%); among those who were tested, 5 (15.6%) had a BDG value of less than 80 pg/mL despite having Candida BSI. Fluconazole sensitivity was 69.5% overall. At 14 days after diagnosis of IC, 49.1% had recovered, with the remainder having an unfavorable outcome (32.4% had died and 18.4% had left against medical advice).Clinical significance: IC is a major concern in Indian ICUs, with a satisfactory outcome in only half of our patients. Serum BDG is a valuable test to diagnose blood culture-negative IC, but more studies are needed to determine its role in the exclusion of IC, as we had a small minority of patients with negative tests despite proven IC.Conclusion: We recommend sending two sets of blood cultures and serum BDG assay for all suspected patients. Initiating empiric antifungal therapy with an echinocandin is advisable, in view of increasing azole resistance and the emergence of Candida auris, with de-escalation to fluconazole for sensitive isolates after clinical stability and blood culture clearance.How to cite this article: Sridharan S, Gopalakrishnan R, Nambi PS, Kumar S, Sethuraman N, Ramasubramanian V. Indian J Crit Care Med 2021;25(3):267-272.

Performance of the (1,3)-Beta-D-Glucan Assay on Bronchoalveolar Lavage Fluid for the Diagnosis of Invasive Pulmonary Aspergillosis.

Detection of (1,3)-beta-D-glucan (BDG), a component of the cell wall of many fungi, was studied in bronchoalveolar lavage fluid (BALF) as a possible aid for the diagnosis of proven/probable invasive pulmonary aspergillosis (IPA). BDG was measured on stored BALF from 13 patients with EORTC/MSGERC defined proven/probable IPA and 26 matched control patients without IPA. The median BALF BDG was 80pg/mL (range < 45-8240pg/mL) in the IPA cohort and 148pg/mL (range < 45-5460pg/mL) in the non-IPA cohort. Using a positive cutoff of ≥ 80pg/mL, sensitivity was 54% and specificity was 38%. Higher cutoff values led to improvement in specificity but a dramatic decrease in sensitivity. ROC/AUC analysis was unable to identify an optimal cutoff value at which test performance was enhanced: AUC 0.43, 95% CI 0.24-0.63. When the BDG assay was performed on BALF, neither sensitivity nor specificity was sufficient for use in the diagnosis of IPA.

Beta-d-Glucan for Diagnosing Pneumocystis Pneumonia: a Direct Comparison between the Wako β-Glucan Assay and the Fungitell Assay.

Measuring serum beta-d-glucan (BDG) is a useful tool for supporting a quantitative PCR (qPCR)-based diagnosis of suspected Pneumocystis pneumonia (PCP) with bronchoalveolar lavage (BAL) fluid. Since the 2000s, the Fungitell assay was the only BDG assay which was FDA cleared and Conformité Européenne (CE) marked. However, the Wako β-glucan test was also recently CE marked and commercialized. We analyzed archived sera from 116 PCP cases (who were considered to have PCP based on compatible clinical and radiological findings plus a BAL fluid qPCR threshold cycle value of ≤28) and 114 controls (those with a BAL fluid qPCR threshold cycle value of >45 and no invasive fungal infection) using the Fungitell and Wako assays in parallel and assessed their diagnostic performance using the manufacturer's proposed cutoffs of 80 pg/ml and 11 pg/ml, respectively. We found the Wako assay to be more specific (0.98 versus 0.87, P < 0.001) and the Fungitell assay to be more sensitive (0.78 versus 0.85, P = 0.039) at the proposed cutoffs. Overall performance, as determined by the area under the receiver operating characteristic curve, was similar for both assays. We determined a new Wako assay cutoff (3.616 pg/ml) to match the sensitivity of the Fungitell assay (0.88 at a cutoff of ≥60 pg/ml). Using this newly proposed cutoff, the specificity of the Wako assay was significantly better than that of the Fungitell assay (0.89 versus 0.82, P = 0.011). In conclusion, the Wako assay performed excellently compared to the Fungitell assay for the diagnosis of presumed PCP based on qPCR. In addition, contrary to the Fungitell assay, the Wako assay allows for single-sample testing with lower inter- and intrarun variability. Finally, we propose an optimized cutoff for the Wako assay to reliably exclude PCP.

Intra-Abdominal Candidiasis

Intra-abdominal candidiasis (IAC) is the second most common form of invasive candidiasis after candidaemia. IAC is a broad term and can be classified on the basis of anatomical site (Candida peritonitis, pancreatic candidiasis, biliary tract candidiasis, gastrointestinal candidiasis, and hepatosplenic candidiasis) as well as clinical setting (community acquired versus nosocomial). The risk factors linked with IAC are candida colonisation, anastomotic leak, multiple instrumentation, long-term broad spectrum antibiotic use, total parenteral nutrition, and immunocompromised state. Clinically, IAC is not different from intraabdominal bacterial infection. Patients generally present with signs and symptoms of intra-abdominal sepsis after not responding to antibiotic therapy and with a background history of multiple surgical interventions or history of delayed source control. Radiological investigations, like ultrasonography and computed tomography scan, not only aid in diagnosis but also assist in differentiating medical from surgical cases. Microbiological diagnosis requires isolation of candida from an intra-abdominal specimen. Differentiation between colonisation and infection is difficult. Generally, progressive and persistent colonisation is associated with high risk of infection. Blood cultures have poor sensitivity for IAC. Non-culture based techniques used for diagnosis are mannan/anti-mannan assay, beta-D glucan assay, and validated polymerase chain reaction. Four types of antifungal strategies described in the literature are prophylaxis (risk factor driven), pre-emptive (colonisation or biomarker driven), empirical (fever driven), and targeted therapy (microbiology driven). Over recent years, global epidemiology has shown a shift from Candida albicans to non-albicans. Local epidemiology plays an important role in selection of the appropriate empirical therapy. The purpose of this review is to discuss different types of IAC based on their classification, risk factors, and management.

Blood product transfusions are associated with an increase in serum (1-3)-beta-d-glucan in infants during the initial hospitalization in neonatal intensive care unit (NICU)

Introduction: Serum (1-3)-beta-d-glucan (BDG) assay has been proposed as an adjunct for the rapid diagnosis of invasive fungal infection (IFI). However, false-positive results have been reported following transfusion of blood products in adults. Aims: To assess the relationship between blood product transfusion and elevated BDG in neonates. Method: Retrospective study including neonates ≤32 weeks, with no fungal colonization or infection, in whom BDG assay was performed for suspicion of IFI. Patients were classified in Transfusion (n = 78) and No Transfusion (n = 55) groups depending on whether or not they were transfused. Clinical, biochemical and microbiological characteristics were recorded. A BDG assay >80 pg/mL was considered as positive. Statistical analyses: bivariate and multivariate logistic regression. Results (median, IQR): One hundred and thirty-three infants were included (gestational age 28.4 weeks, 26.9–30; birth weight 1000 g, 847–1300). BDG was higher in the Transfusion group (170 pg/mL, 65–317) than in the No Transfusion group (57 pg/mL, 34–108; p < 0.001). False-positive BDG assay results were associated with red blood cells (RBC) and fresh frozen plasma (FFP) transfusions. Conclusion: BDG is increased after RBC and FFP transfusions in neonates, leading to overdiagnosis of IFI. Fungal colonization status in peripheral sites and central cultures could help to reduce the risk of misdiagnosis.

Candida Surveillance in Surgical Intensive Care Unit (SICU) in a Tertiary Institution.

BackgroundColonization of patients occurs before development into invasive candidiasis. There is a need to determine the incidences of Candida colonization and infection in SICU patients, and evaluate the usefulness of beta-D-glucan (BDG) assay in diagnosing invasive candidiasis when patients are colonized.MethodsClinical data and fungal surveillance cultures in 28 patients were recorded from November 2010, and January to February 2011. Susceptibilities of Candida isolates to fluconazole, voriconazole, amphotericin B, micafungin, caspofungin and anidulafungin were tested via Etest. The utilities of BDG, Candida score and colonization index for candidiasis diagnosis were compared via ROC.Results30 BDG assays were performed in 28 patients. Four assay cases had concurrent colonization and infection; 23 had concurrent colonization and no infection; three had no concurrent colonization and infection. Of 136 surveillance swabs, 52 (38.24 %) were positive for Candida spp, with C. albicans being the commonest. Azole resistance was detected in C. albicans (7 %). C. glabrata and C. tropicalis were, respectively, 100 and 7 % SDD to fluconazole. All 3 tests showed high sensitivity of 75–100 % but poor specificity ranging 15.38–38.46 %. BDG performed the best (AUC of 0.89).ConclusionsDespite that positive BDG is common in surgical patients with Candida spp colonization, BDG performed the best when compared to CI and CS.

Interference of confounding factors on the use of (1,3)-beta-D-glucan in the diagnosis of invasive candidiasis in the intensive care unit.

Invasive fungal infections (IFIs) are an increasing problem in intensive care units (ICUs), and conventional diagnostic methods are not always reliable or timely enough to deliver appropriate antimicrobial therapy. The dosage of fungal antigens in serum is a promising diagnostic technique, but several confounding factors, such as treatment with immunoglobulins (Ig), albumin, or antifungals, could interfere with the correct interpretation of the (1,3)-beta-D-glucan (BG) assay. This study assessed the reliability of the BG assay and the influence of timing and dosage of major confounding factors on circulating levels of IFI biomarkers. 267 ICU patients who underwent a BG assay were retrospectively studied. The timing and dosage of albumin, use of azole treatment, and infusions of intravenous IgG, red blood cells, concentrated platelets, and frozen plasma were analyzed to find possible correlations with the BG results. The sensitivity and specificity of the BG assay were calculated. The BG test in serum showed high sensitivity (82.9 %) but low specificity (56.7 %). The optimal cut-off for the test was 95.9 pg/mL. The mean BG level in proven invasive candidiasis was around 400 pg/mL. The only factor that was found to significantly confound (p < 0.05) the diagnostic performance of the BG assay was the administration of more than 30 g of albumin within 2 days prior to BG testing. The BG assay remains a useful diagnostic test in ICU patients and the levels of BG are useful in evaluating the positive predictive value of this biomarker. The only confounding factor in our study was the use of albumin.

The utility of bronchoalveolar lavage beta-D-glucan testing for the diagnosis of invasive fungal infections

To investigate the utility of beta-D-glucan (BDG) testing in bronchoalveolar lavage (BAL) fluid for the diagnosis of invasive fungal infection (IFI), as compared to BAL galactomannan (GM). We retrospectively reviewed medical records of 132 consecutive patients at the National Institutes of Health (NIH) in whom BAL BDG testing was performed for diagnosis of pneumonia. Using the European Organization for Research and Treatment of Cancer/Mycoses Study Group guidelines, we determined which patients had proven or probable IFI, and assessed the diagnostic performance of BAL BDG testing, relative to BAL GM. We also determined the reproducibility of the BDG assay in BAL via repeat testing of patient samples. Ten patients had Pneumocystis pneumonia, and 34 patients had proven/probable IFI, including 14 with invasive aspergillosis (IA). BAL BDG was 100% sensitive for Pneumocystis. Although BAL BDG had similar sensitivity to BAL GM for the diagnosis of IA and IFI, it exhibited inferior specificity. Repeat testing demonstrated poor reproducibility of the BDG assay in BAL but not in serum. BDG testing exhibits poor specificity and reproducibility in BAL. Identification of the BAL-specific factors that may interfere with the performance of the assay could improve the clinical usefulness of BAL BDG testing.

Infectious Complications After Unrelated Donor Allogeneic Hematopoietic Cell Transplantation With Or Without Alemtuzumab Based In Vivo Lymphocyte Depletion

The addition of alemtuzumab to conditioning may decrease the incidence of graft versus host disease (GVHD) after unrelated donor (URD) allogeneic hematopoietic cell transplantation (alloHCT) but may also contribute to impaired pathogen immunity due to donor lymphocyte depletion. We identified and graded infections occurring within 6 months after URD alloHCT in 78 individuals treated either with (N=40) or without (N=38) alemtuzumab during alloHCT for hematologic cancers. Conditioning included fludarabine (120 mg/m2 total) and cyclophosphamide (4,800 mg/m2 total) over 4 days with either alemtuzumab (100 mg total days -8 to -4) followed by cyclosporine (AC) or with tacrolimus, methotrexate, and sirolimus (TMS) based GVHD prophylaxis. Both groups received a filgrastim mobilized peripheral blood graft from an 8/8 or 7/8 HLA-matched unrelated donor and received GVHD prophylaxis for 180 days. Filgrastim was administered post HCT until neutrophil recovery. Infections were graded according to Cordonnier et al. (Transplantation 2006). Only proven/probable pulmonary fungal episodes by EORT/MSG criteria were included. Infection prophylaxis during the study period included trimethoprim/sulfamethoxazole BID thrice weekly after HCT engraftment and daily acyclovir or valacyclovir. Fungal prophylaxis was fluconazole until day 100 or either micafungin or voriconazole in persons receiving 1+ week of &gt;1 mg/kg/d prednisone or equivalent. Ceftazidime was administered to persons with neutrophil count &lt;500/μL until recovery. Persons were monitored for CMV, adenovirus, toxoplasmosis (in seropositive persons), EBV (after 2009), and HHV-6 with at least weekly blood PCR. CMV was treated with pre-emptive therapy according to published guidelines. Blood aspergillus glactomannin and beta D-glucan assays were obtained when clinically indicated. The use of AC compared to TMS resulted in greater total infections per patient (4.4 versus 2.8, P&lt;0.0001) but similar rates of grade 3 (most serious) infections (0.5 versus 0.6, P=0.49). CMV reactivation in recipient seropositive persons was more common in AC (24/24 AC arm versus 11/24 TMS arm, P&lt;0.0001). The median duration of CMV viremia was 6 weeks in AC versus 2 weeks in TMS (P=0.001). CMV colitis or pneumonitis occurred in 3 persons treated with AC and in 1 person treated with TMS at a mean of 47 days post alloHCT (range 15-121). Bacterial infections per patient in AC and TMS were similar (1.6 versus 1.1, P=0.08). Clostridium difficile colitis was relatively common (10 episodes AC; 11 episodes TMS). HHV-6 infections were similar (24/40 AC versus 16/38 TMS, P=0.16). HHV-6 encephalitis developed in five individuals (3 TMS, 2 AC). The median blood titer at the time CNS involvement was identified was 15,950 copies/mL (0-40,000 copies/mL) and was not predictive on onset of encephalopathy (P=0.6). EBV infection developed in 9 persons in AC and 6 persons in TMS. Three cases of EBV lymphoproliferative disorder occurred in persons treated with AC. An additional three persons in each AC and TMS were treated pre-emptively with rituximab for EBV viremia. Adenovirus infection developed in 4 persons in each TMS and AC. One person treated with AC developed adenoviral colitis. There was one episode of invasive fungal infection in TMS (Candida krusei blood stream infection) and 4 episodes in AC (3 episodes Candida blood stream infection [2 parapsilosis, 1 albicans], one pulmonary aspergillosis). In summary, the use of AC versus TMS resulted greater total infections and CMV infections but with similar bacterial and fungal infection incidence. Weekly monitoring of HHV-6 by blood PCR was ineffective at predicting development of HHV-6 CNS disease. The rate of invasive fungal infections in this cohort was low. Disclosures: No relevant conflicts of interest to declare.

Evaluation of Plasma (1→3) β-D-glucan Concentrations in Birds Naturally and Experimentally Infected with Aspergillus fumigatus

Avian aspergillosis, most often caused by Aspergillus fumigatus, is a common and devastating disease affecting a range of bird species. Early diagnosis is difficult and often unreliable. The current study evaluated the utility of measuring (1-->3)-beta-D-glucan (BG) concentrations in avian plasma samples to aid in the diagnosis of aspergillosis. We evaluated a commercially available BG assay (Fungitell, Beacon Diagnostics) using 178 plasma samples from naturally infected, experimentally infected, and aspergillosis-free birds. Although there was variation in BG concentration, as reflected by high standard deviations, seabirds with confirmed aspergillosis had the highest mean BG concentrations (M = 3098.7 pg/dl, SD = 5022.6, n = 22) followed by companion avian species and raptors with confirmed aspergillosis (M = 1033.8 pg/dl, SD = 1531.6, n = 19) and experimentally infected Japanese quail (Coturnix japonica; M = 1066.5 pg/dl, SD = 1348.2, n = 17). Variation in severity of disease, differences among species of birds with and without disease, and also different levels in environmental exposure likely contribute to the differences among avian groups. The overall sensitivity and specificity of the BG test for diagnosis of aspergillosis in birds was 60.0 and 92.7%, respectively, with an overall optimized avian cut-offvalue of > or = 461 pg/dl for positive disease. Our findings suggest that, although BG concentrations are highly variable between and within different avian groups, it could serve as a useful adjunctive diagnostic test for aspergillosis that is applicable to multiple avian species in some settings, particularly as a negative predictor of infection.

Early diagnosis of invasive aspergillosis in infants and children.

Effective management of invasive aspergillosis (IA) requires early and accurate diagnosis. Microscopy and culture of appropriate specimens remain the gold standard of mycological diagnosis. High-resolution computed tomography serially performed constitutes a sensitive mode of diagnosis of pulmonary IA in hematological patients, but similar data is lacking for children. While early diagnosis of IA has been improved with galactomannan assay in adults, its use is problematic in young infants due to specificity inferiority. Galactomannan testing also is characterized by low sensitivity in pediatric patients with primary immunodeficiencies including chronic granulomatous disease and Job's syndrome. Beta-D glucan assay has been studied in adult patients with fungal infections including IA. The high negative predictive value of the assay allows its use for excluding IA; no specific data, however, exist for children. Polymerase chain reaction (PCR) may be a powerful tool for early diagnosis of IA but has not been standardized for routine use yet. No studies address the issue in neonates, whereas in children PCR has not been specifically studied but is probably as good as in adults. A high degree of suspicion in immunodeficient pediatric hosts, suggestive clinical and radiological findings, as well as mycological data by application of multiple diagnostic methods including serology and molecular biology, are expected to enhance the capacity to diagnose IA in young patients.