Diagnostic Accuracy of Bronchoalveolar Lavage Fluid Galactomannan for Invasive Aspergillosis

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.

Utility of galactomannan diagnostic assay in rhino-orbito-cerebral mycosis in COVID-19 patients

An increasing number of fungal infections were reported post COVID-19 and many of them were caused by fungi of mixed aetiologies. This study was carried out to assess the utility of serum galactomannan (GM) assay in establishing the etiology of acute rhino-orbito-cerebral mycosis caused by Aspergillus spp. Two serum samples were obtained from 41 suspected post COVID-19 rhino-orbito-cerebral mycosis patients to perform GM assay. Serum GM assay was positive in 68.7% of the cases of proven aspergillosis at cut off OD = 1.0. Serum GM assay can be used as a supplementary test in the diagnosis of rhino-orbito-cerebral mycosis caused by Aspergillus spp.

Current and Future Pathways in Aspergillus Diagnosis

Aspergillus fumigatus has been designated by the World Health Organization as a critical priority fungal pathogen. Some commercially available diagnostics for many forms of aspergillosis rely on fungal metabolites. These encompass intracellular molecules, cell wall components, and extracellular secretomes. This review summarizes the shortcomings of antibody tests compared to tests of fungal products in body fluids and highlights the application of β-d-glucan, galactomannan, and pentraxin 3 in bronchoalveolar lavage fluids. We also discuss the detection of nucleic acids and next-generation sequencing, along with newer studies on Aspergillus metallophores.

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).

Distinguishing Invasive from Chronic Pulmonary Infections: Host Pentraxin 3 and Fungal Siderophores in Bronchoalveolar Lavage Fluids

The multiple forms of pulmonary aspergillosis caused by Aspergillus species are the most common respiratory mycoses. Although invasive, the analysis of diagnostic biomarkers in bronchoalveolar lavage fluid (BALF) is a clinical standard for diagnosing these conditions. The BALF samples from 22 patients with proven or probable aspergillosis were assayed for human pentraxin 3 (Ptx3), fungal ferricrocin (Fc), and triacetylfusarinine C (TafC) in a retrospective study. The infected group included patients with invasive pulmonary aspergillosis (IPA) and chronic aspergillosis (CPA). The BALF data were compared to a control cohort of 67 patients with invasive pulmonary mucormycosis (IPM), non-Aspergillus colonization, or bacterial infections. The median Ptx3 concentrations in patients with and without aspergillosis were 4545.5 and 242.0 pg/mL, respectively (95% CI, p < 0.05). The optimum Ptx3 cutoff for IPA was 2545 pg/mL, giving a sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 100, 98, 95, and 100%, respectively. The median Ptx3 concentration for IPM was high at 4326 pg/mL. Pentraxin 3 assay alone can distinguish IPA from CPA and invasive fungal disease from colonization. Combining Ptx3 and TafC assays enabled the diagnostic discrimination of IPM and IPA, giving a specificity and PPV of 100%.

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.

Definition, diagnosis, and management of COVID-19-associated pulmonary mucormycosis: Delphi consensus statement from the Fungal Infection Study Forum and Academy of Pulmonary Sciences, India

COVID-19-associated pulmonary mucormycosis (CAPM) remains an underdiagnosed entity. Using a modified Delphi method, we have formulated a consensus statement for the diagnosis and management of CAPM. We selected 26 experts from various disciplines who are involved in managing CAPM. Three rounds of the Delphi process were held to reach consensus (≥70% agreement or disagreement) or dissensus. A consensus was achieved for 84 of the 89 statements. Pulmonary mucormycosis occurring within 3 months of COVID-19 diagnosis was labelled CAPM and classified further as proven, probable, and possible. We recommend flexible bronchoscopy to enable early diagnosis. The experts proposed definitions to categorise dual infections with aspergillosis and mucormycosis in patients with COVID-19. We recommend liposomal amphotericin B (5 mg/kg per day) and early surgery as central to the management of mucormycosis in patients with COVID-19. We recommend response assessment at 4–6 weeks using clinical and imaging parameters. Posaconazole or isavuconazole was recommended as maintenance therapy following initial response, but no consensus was reached for the duration of treatment. In patients with stable or progressive disease, the experts recommended salvage therapy with posaconazole or isavuconazole. CAPM is a rare but under-reported complication of COVID-19. Although we have proposed recommendations for defining, diagnosing, and managing CAPM, more extensive research is required.