Serum BDG Research Articles

Identifying optimal serum 1,3-β-D-Glucan cut-off for diagnosing Pneumocystis Jirovecii Pneumonia in non-HIV patients in the intensive care unit

BackgroundSerum (1,3)-β-D-glucan (BDG) detection for diagnosis of Pneumocystis jirovecii pneumonia (PJP) in non-human immunodeficiency virus (HIV) immunocompromised patients lacks intensive care unit (ICU)-specific data. We aimed to assess its performance and determine the optimal cutoff for PJP in ICU population.MethodsThis retrospective study included critically ill non-HIV immunocompromised patients admitted to a medical ICU with suspected pneumonia, undergoing simultaneous microbiological testing for P. jirovecii on lower respiratory tract specimens and serum BDG. Confounders affecting BDG positivity were explored by multivariable logistic regression. Optimal cut-offs were derived from Youden’s index for the entire cohort and subgroups stratified by confounders. Diagnostic performance of serum BDG was estimated at different cutoffs.ResultsOf 400 patients included, 42% were diagnosed with PJP and 58.3% had positive serum BDG. Serum BDG’s area under the receiver operating characteristic curve was 0.90 (0.87–0.93). At manufacturer’s 150 pg/ml cut-off, serum BDG had high sensitivity and negative predictive value (94%), but low specificity and positive predictive value (67%). Confounders associated with a positive serum BDG in PJP diagnosis included IVIG infusion within 3 days (odds ratio [OR] 9.24; 95% confidence interval [CI] 4.09–20.88, p < 0.001), other invasive fungal infections (OR 4.46; 95% CI 2.10–9.49, p < 0.001) and gram-negative bacteremia (OR 29.02; 95% CI 9.03–93.23, p < 0.001). The application of optimal BDG cut-off values determined by Youden’s index (252 pg/ml, 390 pg/ml, and 202 pg/ml) specific for all patients and subgroups with or without confounders improved the specificity (79%, 74%, and 88%) and corresponding PPV (75%, 65%, and 85%), while maintaining reasonable sensitivity and NPV.ConclusionsTailoring serum BDG cutoff specific to PJP and incorporating consideration of confounders could enhance serum BDG’s diagnostic performance in the ICU settings.

Diagnostic performance of the (1-3)-β-d-glucan assay in patients with different risks for invasive fungal diseases.

We evaluated the diagnostic performance of the β-d-glucan (BDG) test (Beijing Gold Mountain River Tech) in diagnosing invasive fungal disease (IFD) and its variations among patients with different risks. Patients≥18 years old who underwent a serum BDG test (positive cutoff value>80 pg/ml) from April 2017 through May 2018 were collected consecutively. Patients were classified into three groups: group 1, patients with host factors as defined by the prior 2008 European Organization for Research and Treatment (EORTC) criteria; group 2, those with extended host factors in 2020 EORTC criteria; and group 3, those without any risk factor mentioned in the criteria. IFD was defined by 2020 EORTC criteria, but BDG was not considered. Diagnostic performance of the serum BDG test was measured by the area under the curve (AUC) of the receiver-operating characteristic curve. Among 469 patients, 15.4% (72/469) were diagnosed with IFD (48/191 [25.1%], 14/144 [9.7%], and 10/134 [7.5%] in groups 1, 2, and 3, respectively). The BDG assay showed fair performance (AUC 0.748 [95% CI: 0.688-0.810]). Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 77.8%, 60.7%, 26.4%, and 93.8%, respectively. PPV was higher in group 1, and NPV was higher in group 3. Additionally, diagnostic odds ratios were 6.73, 2.88, and 5.92 in groups 1, 2, and 3. Immunosuppressant use, non-IFD/Candida colonization, and central venous catheter were associated with false positivity. Clinicians should cautiously interpret the BDG assay, considering the various diagnostic performances depending on the different levels of risk.

Prognostic value of serial (1,3)-β-d-glucan measurements in ICU patients with invasive candidiasis

BackgroundTo determine whether a decrease in serum (1,3)-β-d-glucan (BDG) was associated with reduced mortality and to investigate the performance of BDG downslope in predicting clinical outcome in invasive candidiasis.MethodsObservational cohort study in ICU patients over a ten-year period (2012–2022) in Italy. Proven invasive candidiasis with at least 2 BDG determinations were considered.ResultsIn the study population of 103 patients (age 47 [35–62] years, SAPS II score 67 [52–77]) 68 bloodstream and 35 intrabdominal infections were recorded. Serial measurements showed that in 54 patients BDG decreased over time (BDG downslope group) while in 49 did not (N-BDG downslope group). Candida albicans was the pathogen most frequently isolated (61%) followed by C. parapsilosis (17%) and C. glabrata (12%), in absence of any inter-group difference. Invasive candidiasis related mortality was lower in BDG downslope than in N-BDG downslope group (17% vs 53%, p < 0.01). The multivariate Cox regression analysis showed the association of septic shock at infection occurrence and chronic liver disease with invasive candidiasis mortality (HR [95% CI] 3.24 [1.25–8.44] p = 0.02 and 7.27 [2.33–22.66] p < 0.01, respectively) while a BDG downslope was the only predictor of survival (HR [95% CI] 0.19 [0.09–0.43] p < 0.01). The area under the receiver operator characteristic curve for the performance of BDG downslope as predictor of good clinical outcome was 0.74 (p = 0.02) and our model showed that a BDG downslope > 70% predicted survival with both specificity and positive predictive value of 100%.ConclusionsA decrease in serum BDG was associated with reduced mortality and a steep downslope predicted survival with high specificity in invasive candidiasis.

Dynamic changes in serum (1-3)-β-D-glucan caused by intravenous immunoglobulin infusion: A prospective study

PurposeThe purpose of this study was to investigate the dynamic changes in serum (1-3)-β-D-glucan (BDG) caused by intravenous immunoglobulins (IVIG) infusion in adults. MethodsThis study included patients who received IVIG infusion from October 2021 to October 2022 during hospitalization. We randomly examined two IVIG samples for every patient. Serum samples were collected at nine time points: before (Tpre), immediately (T1-0), 6h (T1-1) and 12h (T1-2) later on the first day; immediately (T2-0) and six hours later (T2-1) on the second day during IVIG infusion, and within three days after IVIG infusion (Ta1, Ta2, and Ta3, respectively). The Friedman test was used for statistical analysis. ResultsA total of 159 serum BDG from 19 patients were included in the analysis. The BDG content of IVIG ranged from 249 pg/ml to 4812 pg/ml. Patients had significantly elevated serum BDG on T1-0 (176 (113, 291) pg/ml, p = 0.002) and Ta1 (310 (199, 470) pg/ml, p < 0.001), compared with Tpre (41 (38, 65) pg/ml). The increments of serum BDG (ΔBDG) were associated with BDG concentration of IVIG (Spearman r = 0.59, p = 0.02). Individuals with abnormal renal function indexes showed higher serum ΔBDG values at Ta1 (403 (207, 484) pg/ml) than patients with normal renal function (172 (85, 316) pg/ml, p = 0.036). ConclusionPatients who received IVIG had significantly higher serum BDG values. Elevated BDG levels correlate with BDG content of IVIG and abnormal renal function indexes.

Study on mNGS Technique in Diagnosing Pneumocystis jirovecii Pneumonia in Non-HIV-Infected Patients.

To investigate the value of metagenomic Next-Generation Sequencing (mNGS) in diagnosing Pneumocystis jirovecii pneumonia (PJP) in non-human immunodeficiency virus (HIV)-infected patients. In this retrospective study, non-HIV-infected patients with PJP and those diagnosed with non-PJP from August 2022 to December 2024 were selected as subjects. The presence of Pneumocystis jirovecii (PJ) and other co-pathogens in bronchoalveolar lavage fluid (BALF) was analyzed, and the diagnostic efficacy of NGS, polymerase chain reaction (PCR) and serum 1,3-β-D-glucan (BDG) in PJP was compared with the reference standard of clinical compound diagnosis. Eighty-nine non-HIV-infected patients were recruited, with dyspnea as the primary symptom (69.66%) and solid malignant tumor as the most common underlying disease (20.22%). Taking clinical compound diagnosis as the reference standard, the sensitivity, specificity, negative predictive value and positive predictive value of mNGS were higher than those detected by PCR and serum BDG. Among 42 non-HIV-infected patients with PJP who underwent mNGS and conventional pathogen detection of BALF, 6 had simple PJ infection and 36 had combined PJ infection. The detection rate of mNGS in mixed infections was significantly higher than that of conventional pathogen detection (85.71 vs 61.70%, P = 0.012). A total of 127 pathogens were detected in BALF using mNGS, among which fungi had the highest detection rate (46.46%). The fungi, viruses and bacteria detected were mainly Pneumocystis jirovecii, human gammaherpesvirus 4 and Acinetobacter baumannii. mNGS is highly effective in diagnosing non-HIV-infected patients with PJP and exhibits ideal performance in the detection of co-pathogens. In addition, it has certain value for clinical diagnosis and guidance of targeted anti-infective drug treatment.

P10 The yeast of our worries: a challenging case of persistent candidaemia following emergency abdominal surgery

Abstract Case summary A 47-year-old woman with a past medical history of osteoarthritis only presented to hospital with abdominal pain three days following a diagnostic colonoscopy performed for suspected bowel malignancy. Upon admission, she was diagnosed with a bowel perforation and subsequently underwent an emergency laparotomy and anterior resection for a newly diagnosed sigmoid adenocarcinoma. Her recovery was complicated by an anastomotic leak requiring multiple washouts due to faeculent peritoneal soiling. Following surgery, she was admitted to the ICU with an open abdomen for vacuum-assisted wound closure and mesh-mediated fascial traction. A sample of peritoneal fluid taken during her initial washout grew Escherichia coli, for which she was initially treated with piperacillin/tazobactam, and later, meropenem, after another E. coli isolate from a sample of intra-abdominal pus collected during a subsequent washout demonstrated piperacillin/tazobactam resistance. Despite treatment with meropenem, the patient continued to have intermittent fevers up to 40°C. Blood cultures taken during a febrile episode grew yeasts identified as Candida glabrata, at which point anidulafungin was commenced empirically. Computed tomography imaging of the chest, abdomen and pelvis did not reveal any potential source of invasive candidiasis. To exclude line infection as the source of the Candida, all central lines were removed, leaving only peripheral venous access. Despite this, the candidaemia continued. In total, 18 blood cultures taken over a period of 19 days grew C. glabrata. After 7 days of empirical treatment with anidulafungin, voriconazole was added in view of the persistent elevation in the patient’s serum β-D-glucan (BDG) and recurrent isolation of C. glabrata from blood cultures. Flucytosine was added after a further 10 days with no effect on the patient’s clinical status. Following removal of the abdominal mesh and the eventual closure of the patient’s abdomen, the time to positivity for her blood cultures gradually increased and eventually became negative at 5 days. Flucytosine was then stopped and anidulafungin and voriconazole were continued. A sustained decline in the patient’s serum BDG was observed thereafter and antifungal treatment was eventually stopped after three negative BDG measurements were obtained.1 Conclusions Fungal mesh infection is a rare but serious complication of abdominal surgery involving mesh insertion.2 To our knowledge, this is the first reported case of abdominal surgical mesh infection caused by C. glabrata. Previously reported cases in the literature have been due to other Candida spp. (albicans, krusei and norvegensis), Aspergillus and Coccidioides spp.1–3 C. glabrata is particularly adept at biofilm formation, causing low therapeutic response to antifungal treatment.4 In this case, source control could not be readily achieved as the mesh was required to aid abdominal closure, resulting in treatment failure despite triple antifungal therapy. This case serves as a stark reminder of the devastating and potentially fatal consequences that may result from this surgical complication and the perils associated with the use of mesh in abdominal surgery when the peritoneum has been soiled.

Diagnostic values of BALF metagenomic next-generation sequencing, BALF real-time PCR and serum BDG for Pneumocystis jirovecii pneumonia in HIV-infected patients.

This study aimed to assess the diagnostic values of bronchoalveolar lavage fluid (BALF) real-time polymerase chain reaction (PCR) and BALF metagenomic next-generation sequencing (mNGS) for Pneumocystis jirovecii pneumonia (PJP) in patients infected with human immunodeficiency virus (HIV). A total of 99 HIV-infected PJP patients and 61 HIV-infected patients diagnosed with non-PJP pneumonia between March 2019 and December 2022 were enrolled. P. jirovecii and multiple other co-pathogens detected in BALF by mNGS were analyzed. The clinical final diagnosis was employed as a benchmark. We compared the diagnostic performance of mNGS in PJP with serum BDG and BALF real-time PCR. The mixed infections detected by mNGS and modifications of antimicrobial treatment were also analyzed. The sensitivity of mNGS test of BALF samples reached 85.86%, which was significantly higher than serum BDG (39.39%, P < 0.001). The sensitivity of BALF P. jirovecii PCR (84.85%) was similar with mNGS (P > 0.05). The specificity of mNGS (100%) was also same as PCR (100.0%), and superior to serum BDG (88.52%, P < 0.001). Besides, mNGS performs remarkably well in identifying co-pathogens of PJP patients infected with HIV. In addition to P. jirovecii, 82 cases (82.83%) of other co-pathogens were identified based on mNGS. Moreover, thirty-four patients (34.34%) increased therapeutic dose of trimethoprim-sulfamethoxazole (TMP-SMZ) based on BALF P. jirovecii PCR. Based on the mNGS results, initial antimicrobial treatment was modified in 86.87% (86/99) of PJP patients. BALF mNGS and real-time PCR are two powerful techniques for rapid diagnosis of PJP with high specificity and sensitivity. Moreover, the benefit of mNGS is that it may identify other organisms besides PJP and it may benefit proper and prompt treatment.

Metagenomic Next-Generation Sequencing for Accurate Diagnosis of Pneumocystis jirovecii Pneumonia: A Comparative Study with Traditional Methods.

Metagenomic next-generation sequencing (mNGS) is a high-throughput sequencing technique that identifies a wide array of pathogens directly from clinical specimens. This study evaluates the diagnostic value of mNGS in Pneumocystis jirovecii pneumonia (PJP) and compares its efficacy with traditional detection methods, including Grocott's Methenamine Silver (GMS) staining, serum (1-3)-β-D-Glucan (BDG) testing, and Lactate Dehydrogenase (LDH) testing. Seventy-eight patients hospitalized between January 2022 and March 2023 with suspected pulmonary infections were included. Patients were eligible for mNGS if they exhibited symptoms such as fever, cough, dyspnea, or progressive hypoxemia, and met specific clinical criteria for PJP. Specimens obtained included bronchoalveolar lavage fluid, sputum, and peripheral blood. Positive rates and pathogen distributions detected by mNGS and traditional methods were compared. In the PJP group, 25%, 37.5%, and 9.38% of patients had solid organ tumors, corticosteroid use, and skin diseases, respectively, significantly higher than in the non-PJP group. The sensitivity and specificity of mNGS were both 100%, significantly higher than those of serum BDG (sensitivity 50%, specificity 81.8%) and LDH (sensitivity 9.3%, specificity 91.3%). Significant differences in microbial composition between the PJP and Non-PJP groups were observed. mNGS detected multiple mixed pathogens in 96.88% of PJP cases, with 68.75% exhibiting mixed bacterial and viral infections. Notably, 71% of patients improved following antibacterial treatment based on mNGS results. mNGS technology shows superior sensitivity and specificity in diagnosing PJP and guides precise treatment for complex pulmonary infections.

1510. Evaluation of Quantitative (1,3)-β-D-glucan in Prediction of Pneumocystis jirovecii Pneumonia in Patients Living with HIV in New York

Abstract Background (1,3)-β-D-glucan (BDG) has been utilized as an indirect marker for Pneumocystis jirovecii pneumonia (PJP). The clinical utility of BDG, however, is limited because of uncertainty in interpreting quantitative values. A correlation was drawn between quantitative BDG and the diagnosis of PJP in hospitalized patients living with human immunodeficiency virus (HIV) at four affiliate campuses of the Montefiore Health System in the Bronx, NY. Methods All Pneumocystis direct fluorescent assays (DFA), polymerase chain reactions (PCR) either from bronchoalveolar lavage (BAL) fluid or sputum, and quantitative BDG assays either from serum or BAL fluid were retrieved from the Montefiore microbiology laboratory (date range: 8/1/18 - 8/31/22). Results from hospitalized patients with HIV whose CD4 count within 3 months were available, with either PJP DFA or PCR result within 7 days of serum BDG and lactate dehydrogenase (LDH) test were selected (n = 146). CD4 count was grouped into &amp;lt; 50 (n = 106), 50-100 (n = 15), 100-200 (n = 16), and &amp;gt;200 (n = 9). BDG, LDH, and CD4 were considered as input variables in a logistic regression model for true PJP status. The area under the curve (AUC) of the empirical receiver operating characteristic (ROC) curve with 95% confidence intervals (CI) was estimated based on trapezoidal area. Comparisons between ROC curve areas were performed via contrast matrix to take differences of the AUC of the empirical ROC curves and chi-square testing. Results Of the 146, 29 had PJP detected and 117 did not. When BDG only was considered, the AUC of the ROC curve was 0.78. When LDH quartiles (cutoffs: 232, 334, and 480 U/L) were considered with BDG, there was a statistically significant increase in AUC (0.84 vs. 0.78; p = 0.025). Adding CD4 group did not influence AUC. Figure 1 ROC curves for BDG only, BDG with CD4 count, BDG with LDH quartile, and BDG with CD4 group and LDH quartile combined Table 1 Area under the curve calculated for the ROC curves for BDG only, BDG with CD4 count, BDG with LDH quartile, and BDG with CD4 group and LDH quartile combined Conclusion The test characteristics (AUC) improved when LDH quartiles were used in conjunction with BDG, suggesting a better prediction of PJP diagnosis when BDG and LDH were considered together. This result supports further investigation of clinical markers of PJP given the limitations of establishing a microbiologic diagnosis. Further steps of the investigation will involve analyzing if other clinical factors including HIV viral load, oxygen saturation, and radiographical reading, influence predictability of PJP. Disclosures All Authors: No reported disclosures

Pneumocystis jirovecii pneumonia in intensive care units: a multicenter study by ESGCIP and EFISG.

Pneumocystis jirovecii pneumonia (PJP) is an opportunistic, life-threatening disease commonly affecting immunocompromised patients. The distribution of predisposing diseases or conditions in critically ill patients admitted to intensive care unit (ICU) and subjected to diagnostic work-up for PJP has seldom been explored. The primary objective of the study was to describe the characteristics of ICU patients subjected to diagnostic workup for PJP. The secondary objectives were: (i) to assess demographic and clinical variables associated with PJP; (ii) to assess the performance of Pneumocystis PCR on respiratory specimens and serum BDG for the diagnosis of PJP; (iii) to describe 30-day and 90-day mortality in the study population. Overall, 600 patients were included in the study, of whom 115 had presumptive/proven PJP (19.2%). Only 8.8% of ICU patients subjected to diagnostic workup for PJP had HIV infection, whereas hematological malignancy, solid tumor, inflammatory diseases, and solid organ transplants were present in 23.2%, 16.2%, 15.5%, and 10.0% of tested patients, respectively. In multivariable analysis, AIDS (odds ratio [OR] 3.31; 95% confidence interval [CI] 1.13-9.64, p = 0.029), non-Hodgkin lymphoma (OR 3.71; 95% CI 1.23-11.18, p = 0.020), vasculitis (OR 5.95; 95% CI 1.07-33.22, p = 0.042), metastatic solid tumor (OR 4.31; 95% CI 1.76-10.53, p = 0.001), and bilateral ground glass on CT scan (OR 2.19; 95% CI 1.01-4.78, p = 0.048) were associated with PJP, whereas an inverse association was observed for increasing lymphocyte cell count (OR 0.64; 95% CI 0.42-1.00, p = 0.049). For the diagnosis of PJP, higher positive predictive value (PPV) was observed when both respiratory Pneumocystis PCR and serum BDG were positive compared to individual assay positivity (72% for the combination vs. 63% for PCR and 39% for BDG). Cumulative 30-day mortality and 90-day mortality in patients with presumptive/proven PJP were 52% and 67%, respectively. PJP in critically ill patients admitted to ICU is nowadays most encountered in non-HIV patients. Serum BDG when used in combination with respiratory Pneumocystis PCR could help improve the certainty of PJP diagnosis.

Comparison of β-1-3-D-Glucan and Candida Mannan Biomarker Assays with Serological Tests for the Diagnosis of Candidemia.

Invasive candidiasis, including bloodstream infection (candidemia), encompasses the most severe forms of Candida infection. Several species-specific and non-specific serological assays are commercially available to aid in diagnosis. This study compared the performance of five such biomarker assays. Serum samples from 14 patients with proven or probable invasive candidiasis, and from 10 control patients, were included in the analysis. A total of 50 serum samples were tested using C. albicans germ tube antibody (CAGTA) assay (Vircell), C. albicans IgM, C. albicans IgG and Candida mannan assays (Dynamiker Biotechnology). Among these samples, the β-1-3-D-glucan (BDG) assay (Fungitell), a laboratory standard for the diagnosis of invasive candidiasis, was positive in 20 (40%), intermediate in five (10%) and negative in 25 (50%). In cases of proven or probable candidemia, the sensitivity and specificity of the BDG assay was 86% and 80%, respectively; the Candida mannan assay, 14% and 86%; the CAGTA test, 57% and 60%; the C. albicans IgM assay, 71% and 60%; and C. albicans IgG assay 29% and 90%. In 4/8 (50%) cases with multiple serum samples, C. albicans IgM was positive sooner than BDG. Thus, when used as a rule-out test for invasive candidiasis, our data suggest that the C. albicans IgM assay may assist antifungal stewardship (over serum BDG).

#2715 AN EXPLORATORY STUDY OF GUT PERMEABILITY IN SUBJECTS ON HAEMODIALYSIS: RESPONSE TO AN ORAL BETA-D-GLUCAN LOAD

Abstract Background and Aims End stage kidney disease (ESKD) is associated with chronic inflammation. A combination of increased gut permeability and impaired hepatic clearance of gut-derived toxins are likely contributory factors to chronic inflammation in ESKD. Gut permeability assessment in kidney impairment is complex as traditional gut permeability probe concentrations are significantly influenced by residual kidney function. (1-3)-β-D glucans (BDG) are glucose polymers found in dietary plant material and also fungi and bacteria. BDG predominantly undergo reticuloendothelial (primarily hepatic) clearance. BDG ingested in the form of fibre are not well absorbed from the small intestine. Elevated serum BDG levels have been previously observed in chronic kidney disease and may reflect systemic translocation of dietary and gut derived microbial fragments from the portal system. This study aimed to establish if there were differences in serum BDG concentrations in individuals with normal kidney function and ESKD following ingestion of a BDG rich meal. Method 20 participants with ESKD receiving haemodialysis via an arteriovenous fistula with evidence of inflammation (a median baseline serum C-reactive protein (CRP) ≥5mg/L over the previous 3 months) and 20 participants with normal kidney function (NKF) were studied. Participants with active infection, autoimmune disease, gastrointestinal disease and hyperkalaemia were excluded. All participants followed a low fibre diet for 48 hours and fasted for 12 hours prior consuming a BDG-rich drink that delivered approximately 10μg/gram of BDG. In the ESKD cohort, the drink was consumed immediately prior to a dialysis session following a 1-day interdialytic gap. In addition to standard of care blood tests, serum BDG levels were measured at baseline, 0.5 hours, 1 hour, 1.5 hours, 2 hours, 3 hours, 4 hours, 6 hours and 48 hours. Serum BDG measurements were analysed with the Fungitell® assay (Associates of Cape Cod, Inc). Faecal calprotectin and faecal alpha-1-antitrypsin were also analysed. Results 20 participants with ESKD receiving haemodialysis (mean age 66.8 years) and 20 participants with NKF (mean age 44.6 years) were recruited. Serum BDG levels were significantly higher at baseline in the ESKD group (29.6pg/ml in the NKF group versus 67.1pg/ml in the ESKD group, p = 0.001) and at all other timepoints throughout the study period (see Fig. 1). There were no significant difference in change from baseline BDG levels between groups. Individual BDG levels taken post meal ingestion are shown in Fig. 2. Baseline serum BDG levels correlated strongly with median baseline high sensitivity CRP over 3 months (p = 0.001) however this relationship was not present when the two groups were examined separately. Faecal calprotectin and faecal alpha-1-antitrypsin did not correlate with baseline serum BDG measurements (p = 0.93, p = 0.78, respectively). Conclusion Elevated BDG levels are observed in ESKD and increase both during and immediately following dialysis after ingestion of a BDG load. In addition to dietary BDG, translocation of gut-derived microbial BDG into the systemic circulation may play an important role in contributing to systemic inflammation observed in advanced kidney disease. Elevated BDG may reflect increased gut permeability which may be secondary to uraemic toxin related gut barrier dysfunction or splanchnic ischaemia related to ultrafiltration.

Metagenomic next‐generation sequencing for pneumocystis jirovecii pneumonia in patients with connective tissue disease

AbstractBackgroundAccurate diagnosis of Pneumocystis jirovecii pneumonia (PJP) is challenging, and the delayed diagnosis of PJP is associated with high mortality in patients with connective tissue disease (CTD). Metagenomic next‐generation sequencing (mNGS) technology facilitates etiological diagnosis of various infectious diseases, with promising application in diagnosing PJP. This study aimed to investigate the value of mNGS using bronchoalveolar lavage fluid (BALF) for diagnosing PJP infection.MethodsData from 55 patients with CTD and suspected pulmonary infection was retrospectively collected and analysed. A PJP group and non‐PJP group were formed. The clinical manifestations, laboratory test results, treatment methods, and outcomes were summarized. BALF mNGS results were compared with traditional pathogen tests (TPT) and serum 1,3‐beta‐D‐glucan (BDG) testing.ResultsThe mean age of PJP patients was 54 years, and 59% (10/17) of the patients were female. A significant difference was found between the average daily dose of prednisone administered to the PJP group and non‐PJP group (25 mg vs. 16 mg, P &lt; 0.001). The PJP group had a significantly higher incidence of dyspnoea (88% [15/17] vs. 16% [6/38], P &lt; 0.001) and elevated serum BDG level (167.73 vs. 30.67 pg/mL, P &lt; 0.001). BALF mNGS was more sensitive than both TPT (100% [95% confidence interval {CI}: 77.1%–100%] vs. 11.8% [95% CI: 2.1%–37.7%], P &lt; 0.001) and serum BDG (100% [95% CI: 77.1%–100%] vs. 85.7% [95% CI: 42%–99.2%], P &lt; 0.001). BALF mNGS was more specific than serum BDG (89.5% [95% CI: 74.3%–96.6%] vs. 46.7% [95% CI: 22.3%–72.6%], P = 0.493). Co‐infection with cytomegalovirus (CMV) was more common in the PJP patients than in the non‐PJP patients (59% [10/17] vs. 11% [4/38], respectively, P &lt; 0.001).ConclusionBALF mNGS technology is highly effective for diagnosing PJP in patients with CTD and identifying co‐infections.

Impact of intravenous immunoglobulins on serum (1-3)-β-D-glucan

BackgroundThe purpose of this study was to evaluate the changes in serum (1-3)-β-D-glucan (BDG) in adults due to intravenous immunoglobulins (IVIG) infusion and the factors that affect these changes. MethodsPatients who had BDG tests both before and after IVIG infusion during hospitalization were retrospectively included, and trends in BDG values were analyzed before and after IVIG infusion. Factors associated with false-positive BDG were then explored using univariate analysis. ResultsA total of 347 serum BDG tests from 131 patients were included in the analysis, and 71.8% (94/131) patients had false positive serum BDG after IVIG infusion. All BDG values on day 7 were negative. Univariate analysis showed that patients with false positive BDG tests had higher daily IVIG doses (P = 0.043) and higher levels of serum IgG increments (P = 0.001). The median peak blood BDG on day 1 after completion of IVIG infusion was 199.6 (154.5–277.7, inter-quartile ranges (IQR)) pg/mL, and both the peak BDG and incremental BDG values (ΔBDG, BDG at the first day after IVIG infusion minus BDG before infusion) were slightly and positively correlated with ΔIgG (BDG vs. ΔIgG, P = 0.0016; ΔBDG vs. ΔIgG, P = 0.0003). ConclusionMost adults showed false positive BDG tests after IVIG infusion and negative BDG tests within 1 week. Daily IVIG dosage may contribute to the evaluation of ΔBDG.

Risk factors associated with Pneumocystis jirovecii pneumonia in non-HIV immunocompromised patients and co-pathogens analysis by metagenomic next-generation sequencing

BackgroundPneumocystis jirovecii pneumonia (PJP) is one of the most common opportunistic infections in immunocompromised patients. However, the accurate prediction of the development of PJP in non-HIV immunocompromised patients is still unclear.MethodsNon-HIV immunocompromised patients confirmed diagnosis of PJP by the clinical symptoms, chest computed tomography and etiological results of metagenomic next-generation sequencing (mNGS) were enrolled as observation group. Another group of matched non-HIV immunocompromised patients with non-PJP pneumonia were enrolled to control group. The risk factors for the development of PJP and the co-pathogens in the bronchoalveolar lavage fluid (BALF) detected by mNGS were analyzed. ResultsA total of 67 (33 PJP, 34 non-PJP) participants were enrolled from Fujian Provincial Hospital. The ages, males and underlying illnesses were not significantly different between the two groups. Compared to non-PJP patients, PJP patients were more tends to have the symptoms of fever and dyspnea. The LYM and ALB were significantly lower in PJP patients than in non-PJP patients. Conversely, LDH and serum BDG in PJP patients were significantly higher than in non-PJP controls. For immunological indicators, the levels of immunoglobulin A, G, M and complement C3, C4, the numbers of T, B, and NK cells, had no statistical difference between these two groups. Logistic multivariate analysis showed that concomitant use of corticosteroids and immunosuppressant (OR 14.146, P = 0.004) and the lymphocyte counts < 0.7 × 109/L (OR 6.882, P = 0.011) were risk factors for the development of PJP in non-HIV immunocompromised patients. 81.82% (27/33) and 64.71% (22/34) mixed infections were identified by mNGS in the PJP group and non-PJP group separately. CMV, EBV and Candida were the leading co-pathogens in PJP patients. The percentages of CMV and EBV identified by mNGS in PJP group were significantly higher than those in the control group(p < 0.005). ConclusionsClinicians should pay close attention to the development of PJP in non-HIV immunocompromised patients who possess the risk factors of concomitant use of corticosteroids and immunosuppressant and the lymphocyte counts < 0.7 × 109/L. Prophylaxis for PJP cannot rely solely on CD4+ T counts in non-HIV immunocompromised patients. Whether CMV infection increases the risk of PJP remains to be further investigated.

Siderophore-Based Noninvasive Differentiation of Aspergillus fumigatus Colonization and Invasion in Pulmonary Aspergillosis.

Germination from conidia to hyphae and hyphal propagation of Aspergillus fumigatus are the key pathogenic steps in the development of invasive pulmonary aspergillosis (IPA). By applying in vitro observations in a clinical study of 13 patients diagnosed with probable IPA, here, we show that the transition from colonization to the A. fumigatus invasive stage is accompanied by the secretion of triacetylfusarinine C (TafC), triacetylfusarinine B (TafB), and ferricrocin (Fc) siderophores into urine, with strikingly better sensitivity performance than serum sampling. The best-performing index, the TafC/creatinine index, with a median value of 17.2, provided 92.3% detection sensitivity (95% confidence interval [CI], 64.0 to 99.8%) and 100% specificity (95% CI, 84.6 to 100%), i.e., substantially better than the corresponding indications provided by galactomannan (GM) and β-d-glucan (BDG) serology. For the same patient cohort, the serum GM and BDG sensitivities were 46.2 and 76.9%, respectively, and their specificities were 86.4 and 63.6%, respectively. The time-dependent specific appearance of siderophores in the host's urine represents an impactful clinical diagnostic advantage in the early discrimination of invasive aspergillosis from colonization. A favorable concentration of TafC in a clinical specimen distant from a deep infection site enables the noninvasive sampling of patients suffering from IPA. IMPORTANCE The importance of this research lies in the demonstration that siderophore analysis can distinguish between asymptomatic colonization and invasive pulmonary aspergillosis. We found clear associations between phases of fungal development, from conidial germination to the proliferative stage of invasive aspergillosis, and changes in secondary metabolite secretion. The critical extracellular fungal metabolites triacetylfusarinines C and B are produced during the polarized germination or postpolarized growth phase and reflect the morphological status of the proliferating pathogen. False positivity in Aspergillus diagnostics is minimized as mammalian cells do not synthesize Aspergillus siderophore or mycotoxin molecules.

Diagnosis of Aspergillosis in Horses.

Invasive pulmonary aspergillosis (IPA) may be a rare cause of granulomatous pneumonia in horses. The mortality of IPA is almost 100%; direct diagnostic tools in horses are needed. Bronchoalveolar lavage fluid (BALF) and serum samples were collected from 18 horses, including individuals suffering from IPA (n = 1), equine asthma (EA, n = 12), and 5 healthy controls. Serum samples were collected from another 6 healthy controls. Samples of BALF (n = 18) were analyzed for Aspergillus spp. DNA, fungal galactomannan (GM), ferricrocin (Fc), triacetylfusarinin C (TafC), and gliotoxin (Gtx). Analysis of 24 serum samples for (1,3)-β-D-glucan (BDG) and GM was performed. Median serum BDG levels were 131 pg/mL in controls and 1142 pg/mL in IPA. Similar trends were observed in BALF samples for GM (Area under the Curve (AUC) = 0.941) and DNA (AUC = 0.941). The fungal secondary metabolite Gtx was detected in IPA BALF and lung tissue samples (86 ng/mL and 2.17 ng/mg, AUC = 1).

Metagenomic next-generation sequencing for the diagnosis of Pneumocystis jirovecii Pneumonia in critically pediatric patients

ObjectiveThe aim of this study was to evaluate the effectiveness of metagenomic next-generation sequencing (mNGS) for the diagnosis of Pneumocystis jirovecii Pneumonia (PCP) in critically pediatric patients.MethodsSeventeen critically pediatric patients with PCP and sixty patients diagnosed with non-PCP pneumonia who were admitted in pediatric intensive care unit between June 2018 and July 2021 were enrolled. Conventional methods and mNGS for detecting Pneumocystis jirovecii (P. jirovecii) were compared. The patients’ demographics, comorbidities, laboratory test results, antibiotic treatment response and 30 day mortality were analyzed.ResultThe mNGS showed a satisfying diagnostic performance with a sensitivity of 100% in detecting P. jirovecii compared with Gomori methenamine silver staining (5.9%), serum (1,3)-β-D-glucan (86.7%) and and LDH (55.6%). The diagnostic specificity of mNGS for PCP was higher than that of serum BDG (56.7%) and LDH (71.4%). In PCP group, over one thirds’ cases had mixed infections. Compared with survivors, non-survivors had higher stringently mapped read numbers (SMRNs) in bronchoalveolar lavage fluid (BALF) sample (P < 0.05), suggesting SMRNs were closely associated with the severity of response. The detection for P. jirovecii by mNGS both in BALF and blood samples reached a concordance rate of 100%, and the SMRNs in the BALF were remarkably higher than that in blood samples. Initial antimicrobial treatment was modified in 88.2% of PCP patients based on the mNGS results.ConclusionThe mNGS is a potential and efficient technology in diagnosing PCP and shows a satisfying performance in the detection of co-pathogens. Both blood and BALF samples for mNGS are suggested for the presumptive diagnosis of PCP.

Serum Beta-D-Glucan in the Diagnosis of Invasive Fungal Disease in Neonates, Children and Adolescents: A Critical Analysis of Current Data.

β-D-glucan (BDG) is a cell wall component of many pathogenic fungi. The detection of BDG as an assay is clinically broadly used as a diagnostic tool. However, the current data on BDG in paediatrics are limited, prompting specific considerations about when BDG can be used in neonates and children. We aimed to analyse the available data for the use of serum BDG in neonates and immunocompromised children and adolescents; as well as to understand the extent and characteristics of the use of BDG in children in Europe.

P408 Evaluation of fungal serum biomarkers in the diagnosis and for monitoring patients with post tuberculosis chronic pulmonary aspergillosis

Poster session 3, September 23, 2022, 12:30 PM - 1:30 PMObjectivesThe evaluation of serum β-D-glucan, galactomannan, and Aspergillus fumigatus specific IgG in the diagnosis and clinical management of patients with chronic pulmonary aspergillosis.MethodsConsecutive patients with a past history of pulmonary tuberculosis (PTB) with clinical suspicion of chronic pulmonary aspergillosis (CPA) attending the outpatient services of PGIMER, Chandigarh were included from August 2019 to August 2021, and CPA was defined as described by Denning et al. including both radiological and mycological evidence. Age and sex-matched post-PTB individuals selected from a population attending the chest clinic were enrolled as controls. Serum samples were obtained from all participants and testing for serum β-D-glucan (Fungitell, CapeCod), galactomannan (Platelia, BioRad) and Aspergillus fumigatus specific IgG (ImmunoCAP, Phadia) was performed as per manufacturer's instructions.ResultsA total of 105 post-TB patients with CPA and 11 controls were enrolled. Aspergillus fumigatus (n = 8) was the most commonly isolated species, followed by A. flavus (n = 4), and A. niger (n = 2). The mean A. fumigatus specific IgG levels, serum galactomannan index and BDG levels were higher among CPA cases vs. controls at 101.4 mgA/l vs. 11.8 mgA/l, P-value: .0001; 0.73 vs. 0.35, P-value: .3134; and 133.7 pg/ml vs. 32.37 pg/ml, P-value: .012, respectively (Figs. 1a, b, c). The serum BDG had an area under curve 0.834 ± 0.044 (95% CI: 0.748-0.920) on the ROC curve with a sensitivity of 57.1% and specificity of 100% at the kit cut-off of 80 pg/ml (Fig. 2a). Comparison between CPA patients with multiple (n = 38) versus single lobe (n = 67) involvement showed comparable A. fumigatus specific IgG levels (112.3 vs. 93.8; P-value: .133 respectively) while galactomannan index and BDG levels were higher in cases with multiple vs. single lobe involvement (0.94 vs. 0.57, P-value: .117), and (174.3 vs. 105.3, P-value: .0071), respectively (Fig. 1d, e, f). There was a significant association of BDG value with the severity of dyspnea (P-value: .002) and a trend of higher A. fumigatus specific IgG was also seen to correlate with the severity of dyspnea (Fig. 2b and 2c).ConclusionBDG assay can serve as an adjunct in the diagnosis of patients with CPA. An association of higher levels of BDG with multiple lobe involvement and severe dyspnea could be due to more extensive tissue damage associated with a greater release of antigen in circulation during progressive disease. More studies with a larger number of control samples, preferably with multi-center coordination can further improve our understanding of this test's applicability in routine practice.