The performance of bronchoalveolar lavage Aspergillus PCR testing in solid organ transplant recipients with invasive pulmonary aspergillosis.

BACKGROUND: Invasive aspergillosis affects solid organ transplant (SOT) recipients, carrying a high risk of mortality and morbidity in this population. Rapid and accurate diagnosis is essential to ensure the initiation of correct antifungal therapy. We aimed to evaluate the performance of the bronchoalveolar lavage (BAL) Eurofins Viracor Aspergillus PCR (AspPCR) in diagnosing invasive pulmonary aspergillosis (IPA) in SOT recipients. METHODS: We conducted a multicenter retrospective study of SOT recipients in Arizona from February 2019 to December 2022 who had AspPCR done at the time of the clinical encounter. Probable IPA was defined as a positive BAL culture with Aspergillus spp. with clinical and imaging findings of IPA per EORTC/MSGERC criteria. RESULTS: Ninety-nine SOT recipients with 131 encounters with BAL AspPCR testing were included. The median age was 66, the majority were White, non-Hispanics (60%), and males (66%). Among the participants, 93 lung transplant recipients with 87 of the encounters received antifungal prophylaxis active against Aspergillus spp. Sixty-four encounters had BAL galactomannan (GM), all of which had BAL GM <1 OD, and one case had a serum GM of 10 OD. Nine cases met the definition of IPA. The sensitivity of the BAL AspPCR was 67% (95% CI 30%-93%), and the specificity was 98% (95% CI 93%-99%). CONCLUSION: BAL AspPCR had moderate sensitivity and high specificity in identifying IPA in our cohort of SOT recipients. Further studies in populations with a higher prevalence of IPA are needed to evaluate the performance of this test.

The Utility of Galactomannan and Polymerase Chain Reaction Assays in Bronchoalveolar Lavage for Diagnosis of Chronic Pulmonary Aspergillosis.

The diagnosis of chronic pulmonary aspergillosis (CPA) is established by combined clinic-radio-microbiological criteria. Out of the different microbiological criteria, a positive serology for Aspergillus-specific IgG levels is the cornerstone of diagnosis. Alternatively, other microbiological evidence are sometimes sought viz., positive Aspergillus antigen (broncho-alveolar lavage fluid, i.e., BALF galactomannan ≥ 1.0), histopathological demonstration of the fungi following lung biopsy or resection, demonstration of hyaline septate hyphae in direct microscopy resembling Aspergillus spp. or its growth on a respiratory specimen. However, the exact roles of BALF- GM and the newer BALF-PCR have not been confirmed by studies till date. This study enrolled 210 patients with suspected CPA. Of the participants, 88 patients met the criteria for CPA, whereas 122 patients had an alternative diagnosis. The sensitivity-specificity of AsperGenius® PCR and "in-house" PCR were 52.27(36.69-67.54) %-33.78 (23.19-45.72) % and 36.36 (22.41-52.23) %-39.19 (28.04-51.23) % respectively. The sensitivity/specificity of BALF (> 1.0) and serum galactomannan (> 1.0) were 46.55% (33.34-60.13)/64.08% (54.03-73.3) and 29.82% (22.05-37.6)/86.84% (81.1-92.59) respectively. The optimal cut-off values for BALF-Galactomannan and serum galactomannan in diagnosing CPA were found to be 0.69 (sensitivity: 64%; specificity: 53%) and 0.458 (sensitivity: 67%; specificity: 64%) respectively. This results of this study suggests that Aspergillus PCR from BAL may not be a good "rule-in" test for diagnosing CPA. While the performances of GM in BAL and serum may be better than PCR, it should be best used in conjunction with other clinical, radiological, and other microbiological characteristics.

Clinical Impact of Polymerase Chain Reaction-Based Aspergillus and Azole Resistance Detection in Invasive Aspergillosis: A Prospective Multicenter Study.

BACKGROUND: Invasive aspergillosis (IA) by a triazole-resistant Aspergillus fumigatus is associated with high mortality. Real-time resistance detection will result in earlier initiation of appropriate therapy. METHODS: In a prospective study, we evaluated the clinical value of the AsperGenius polymerase chain reaction (PCR) assay in hematology patients from 12 centers. This PCR assay detects the most frequent cyp51A mutations in A. fumigatus conferring azole resistance. Patients were included when a computed tomography scan showed a pulmonary infiltrate and bronchoalveolar fluid (BALf) sampling was performed. The primary end point was antifungal treatment failure in patients with azole-resistant IA. RESULTS: Of 323 patients enrolled, complete mycological and radiological information was available for 276 (94%), and probable IA was diagnosed in 99/276 (36%). Sufficient BALf for PCR testing was available for 293/323 (91%). Aspergillus DNA was detected in 116/293 (40%) and A. fumigatus DNA in 89/293 (30%). The resistance PCR was conclusive in 58/89 (65%) and resistance detected in 8/58 (14%). Two had a mixed azole-susceptible/azole-resistant infection. In the 6 remaining patients, treatment failure was observed in 1. Galactomannan positivity was associated with mortality (P = .004) while an isolated positive Aspergillus PCR was not (P = .83). CONCLUSIONS: Real-time PCR-based resistance testing may help to limit the clinical impact of triazole resistance. In contrast, the clinical impact of an isolated positive Aspergillus PCR on BALf seems limited. The interpretation of the EORTC/MSGERC PCR criterion for BALf may need further specification (eg, minimum cycle threshold value and/or PCR positive on >1 BALf sample).

An overview of using fungal DNA for the diagnosis of invasive mycoses.

INTRODUCTION: Fungal PCR has undergone considerable standardization and, together with the availability of commercial assays, external quality assessment schemes, and extensive performance validation data, is ready for widespread use for the screening and diagnosis of invasive fungal disease (IFD). AREAS COVERED: Drawing on the experience and knowledge of the leads of the various working parties of the Fungal PCR initiative, this review will address general considerations concerning the use of molecular tests for the diagnosis of IFD, before focusing specifically on the technical and clinical aspects of molecular testing for the main causes of IFD and recent technological developments. EXPERT OPINION: For infections caused by Aspergillus, Candida, and Pneumocystis jirovecii, PCR testing is recommended, and combination with serological testing will likely enhance the diagnosis. For other IFD (e.g. mucormycosis), molecular diagnostics represent the only non-classical mycological approach toward diagnoses, and continued performance validation and standardization have improved confidence in such testing. The emergence of antifungal resistance can be diagnosed, in part, through molecular testing. Next-generation sequencing has the potential to significantly improve our understanding of fungal phylogeny, epidemiology, pathogenesis, mycobiome/microbiome, and interactions with the host, while identifying novel and existing mechanisms of antifungal resistance and novel diagnostic/therapeutic targets.

A Laboratory-Based Study on Multiple Biomarker Testing in the Diagnosis of COVID-19-Associated Pulmonary Aspergillosis (CAPA): Real-Life Data.

(1) Background: Coronavirus disease 2019 (COVID-19)-associated pulmonary aspergillosis (CAPA) raises concerns to contribute to an increased mortality. The incidence of CAPA varies widely within hospitals and countries, partly because of difficulties in obtaining a reliable diagnosis. (2) Methods: Here, we assessed Aspergillus culture-positive and culture-negative respiratory tract specimens via direct fungal microscopy (gold standard) and compared the results with galactomannan enzyme immunoassay (GM-EIA) and Aspergillus PCR. (3) Results: 241 respiratory samples from patients suffering from SARS-CoV-2 pneumonia were evaluated. Results showed both diagnostic tools, Aspergillus PCR and GM-EIA, to be positive or negative displaying a sensitivity of 0.90, a specificity of 0.77, a negative predictive value (NPV) of 0.95, and a positive predictive value (PPV) of 0.58 in Aspergillus sp. culture and microscopic-positive specimens. Non-bronchoalveolar lavage (BAL) samples, obtained within a few days from the same patient, showed a high frequency of intermittent positive or negative GM-EIA or Aspergillus PCR results. Positivity of a single biomarker is insufficient for a proper diagnosis. A broad spectrum of Aspergillus species was detected. (4) Conclusions: Our study highlights the challenges of combined biomarker testing as part of diagnosing CAPA. From the results presented, we highly recommend the additional performance of direct microscopy in respiratory specimens to avoid overestimation of fungal infections by applying biomarkers.

Aspergillus Polymerase Chain Reaction-An Update on Technical Recommendations, Clinical Applications, and Justification for Inclusion in the Second Revision of the EORTC/MSGERC Definitions of Invasive Fungal Disease.

Aspergillus polymerase chain reaction testing of blood and respiratory samples has recently been included in the second revision of the EORTC/MSGERC definitions for classifying invasive fungal disease. This is a result of considerable efforts to standardize methodology, the availability of commercial assays and external quality control programs, and additional clinical validation. This supporting article provides both clinical and technical justifications for its inclusion while also summarizing recent advances and likely future developments in the molecular diagnosis of invasive aspergillosis.

Invasive pulmonary aspergillosis treatment duration in haematology patients in Europe: An EFISG, IDWP-EBMT, EORTC-IDG and SEIFEM survey.

Invasive pulmonary aspergillosis (IPA) optimal duration of antifungal treatment is not known. In a joint effort, four international scientific societies/groups performed a survey to capture current practices in European haematology centres regarding management of IPA. We conducted a cross-sectional internet-based questionnaire survey in 2017 to assess practices in sixteen European countries concerning IPA management in haematology patients including tools to evaluate treatment response, duration and discontinuation. The following four groups/societies were involved in the project: European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Fungal Infection Study Group (EFISG), Infectious Diseases Working Party-European Society for Blood and Bone Marrow Transplantation (IDWP-EBMT), European Organisation for Research and Treatment-Infectious Disease group (EORTC-IDG) and Sorveglianza Epidemiologica Infezioni nelle Emopatie (SEIFEM). A total of 112 physicians from 14/16 countries answered the survey. Galactomannan antigen was available in serum and bronchoalveolar lavage in most centres (106/112 [95%] and 97/112 [87%], respectively), quantitative Aspergillus PCR in 27/112 (24%) centres, ß-D-glucan in 24/112 (21%) and positron emission tomography in 50/112 (45%). Treatment duration differed between haematological malignancies, with a median duration of 6 weeks [IQR 3-12] for patients with AML, 11 [4-12] for patients with allogenic stem cell transplantation and GvHD and 6 [3-12] for patients with lymphoproliferative disease. Treatment duration significantly differed according to country. Essential IPA biomarkers are not available in all European countries, and treatment duration is highly variable according to country. It will be important to provide guidelines to help with IPA treatment cessation with algorithms according to biomarker availability.

New Concepts in Diagnostics for Invasive Mycoses: Non-Culture-Based Methodologies.

Non-culture-based diagnostics have been developed to help establish an early diagnosis of invasive fungal infection. Studies have shown that these tests can significantly impact the diagnosis of infection in high risk patients. Aspergillus galactomannan EIA testing is well-recognized as an important adjunct to the diagnosis of invasive aspergillosis and can be detected in serum, bronchoalveolar lavage and other fluids. Galactomannan testing used along with PCR testing has been shown to be effective when integrated into care paths for high risk patients for both diagnoses and as a surrogate marker for outcome when used in serial testing. Beta-d-glucan assays are non-specific for several fungal genera including Aspergillus and Candida and in high risk patients have been an important tool to augment the diagnosis. Lateral flow technology using monoclonal antibodies to Aspergillus are available that allow rapid testing of clinical samples. While standard PCR for Candida remains investigational, T2 magnetic resonance allows for the rapid diagnosis of Candida species from blood cultures. Aspergillus PCR has been extensively validated with standardized approaches established for these methods and will be included in the diagnostic criteria in the revised European Organization for Research and Treatment of Cancer/Mycoses Study Group (EORTC-MSG) definitions. Finally, these non-culture-based tests can be used in combination to significantly increase the detection of invasive mycoses with the ultimate aim of establishing an early diagnosis of infection.

A New Age in Molecular Diagnostics for Invasive Fungal Disease: Are We Ready?

Invasive fungal diseases (IFDs) present an increasing global burden in immunocompromised and other seriously ill populations, including those caused by pathogens which are inherently resistant or less susceptible to antifungal drugs. Early diagnosis encompassing accurate detection and identification of the causative agent and of antifungal resistance is critical for optimum patient outcomes. Many molecular-based diagnostic approaches have good clinical utility although interpretation of results should be according to clinical context. Where an IFD is in the differential diagnosis, panfungal PCR assays allow the rapid detection/identification of fungal species directly from clinical specimens with good specificity; sensitivity is also high when hyphae are seen in the specimen including in paraffin-embedded tissue. Aspergillus PCR assays on blood fractions have good utility in the screening of high risk hematology patients with high negative predictive value (NPV) and positive predictive value (PPV) of 94 and 70%, respectively, when two positive PCR results are obtained. The standardization, and commercialization of Aspergillus PCR assays has now enabled direct comparison of results between laboratories with commercial assays also offering the simultaneous detection of common azole resistance mutations. Candida PCR assays are not as well standardized with the only FDA-approved commercial system (T2Candida) detecting only the five most common species; while the T2Candida outperforms blood culture in patients with candidemia, its role in routine Candida diagnostics is not well defined. There is growing use of Mucorales-specific PCR assays to detect selected genera in blood fractions. Quantitative real-time Pneumocystis jirovecii PCRs have replaced microscopy and immunofluorescent stains in many diagnostic laboratories although distinguishing infection may be problematic in non-HIV-infected patients. For species identification of isolates, DNA barcoding with dual loci (ITS and TEF1α) offer optimal accuracy while next generation sequencing (NGS) technologies offer highly discriminatory analysis of genetic diversity including for outbreak investigation and for drug resistance characterization. Advances in molecular technologies will further enhance routine fungal diagnostics.

Aspergillus fumigatus Detection and Risk Factors in Patients with COPD-Bronchiectasis Overlap.

The role of Aspergillus fumigatus in the airways of chronic obstructive pulmonary disease (COPD) patients with bronchiectasis is currently unclear. We searched for a sensitive and noninvasive method for A. fumigatus detection in the sputum of COPD patients and addressed potential risk factors for its presence. Induced sputum samples of 18 COPD patients and 17 COPD patients with bronchiectasis were analyzed for the presence of A. fumigatus by culture, galactomannan detection, and PCR. Of the patients with COPD-bronchiectasis overlap, 23.5% had a positive culture for A. fumigatus versus 10.5% of COPD patients without bronchiectasis (p = 0.39). The median sputum galactomannan optical density index was significantly higher in patients with COPD and bronchiectasis compared with patients with COPD alone (p = 0.026) and ranged between the levels of healthy controls and A. fumigatus-colonized cystic fibrosis patients. Both the presence of bronchiectasis and the administration of systemic corticosteroids were associated with sputum galactomannan (p = 0.0028 and p = 0.0044, respectively) and showed significant interaction (p interaction = 0.022). PCR for Aspergillus was found to be a less sensitive method, but was critically dependent on the extraction technique. The higher sputum galactomannan levels suggest a more abundant presence of A. fumigatus in the airways of patients with COPD-bronchiectasis overlap compared with patients with COPD without bronchiectasis, particularly when systemic corticosteroids are administered.

Predicting Invasive Aspergillosis in Hematology Patients by Combining Clinical and Genetic Risk Factors with Early Diagnostic Biomarkers.

Personalized medicine provides a strategic approach to the management of IA. The incidence of IA in high-risk hematology populations is relatively low (<10%), despite unavoidable Aspergillus exposure in patients with a potentially similar clinical risk. Nonclinical variables, including genetic mutations that increase susceptibility to IA, could explain why only certain patients develop the disease. This study screened for mutations in 322 hematology patients classified according to IA status and developed a predictive model based on genetic risk, established clinical risk factors, and diagnostic biomarkers. Genetic markers were determined by real-time PCR and, with clinical risk factors and Aspergillus PCR results, subjected to multilogistic regression analysis to identify a best-fit model for predicting IA. The probability of IA was calculated, and an optimal threshold was determined. Mutations in dectin-1 (rs7309123) and DC-SIGN (rs11465384 and rs7248637), allogeneic stem cell transplantation, respiratory virus infection, and Aspergillus PCR positivity were all significant risk factors for developing IA and were combined in a predictive model. An optimal threshold requiring three positive factors generated a mean sensitivity/specificity of 70.4%/89.2% and a probability of developing IA of 56.7%. In patients with no risk factors, the probability of developing IA was 2.4%, compared to >79.1% in patients with four or more factors. Using a risk threshold of 50%, preemptive therapy would have been prescribed for 8.4% of the population. This pilot study shows that patients can be stratified according to risk of IA, providing personalized medicine based on strategic evidence for the management of IA. Further studies are required to confirm this approach.

Performance of Aspergillus PCR in cerebrospinal fluid for the diagnosis of cerebral aspergillosis.

OBJECTIVES: Cerebral aspergillosis is a rare but often fatal form of invasive aspergillosis that remains difficult to diagnose. The literature has shown the value of Aspergillus PCR in blood-derived samples for the diagnosis of invasive aspergillosis but provides far less information for cerebrospinal fluid (CSF) in cerebral aspergillosis. Here, we evaluated the usefulness of an Aspergillus PCR assay performed on CSF for the diagnosis of cerebral aspergillosis. METHODS: This retrospective study involved 72 patients with suspected cerebral aspergillosis for a total of 88 CSF samples in whom CSF Aspergillus PCR was performed. RESULTS: Seventeen patients had proven/probable invasive aspergillosis according to the European Organization for Research and Treatment of Cancer/Mycoses Study Group criteria, including 12 cases of proven/probable cerebral aspergillosis. Aspergillus PCR in CSF was positive in nine of the twelve patients with cerebral aspergillosis, i.e. 75% sensitivity. In contrast, CSF culture was positive for Aspergillus in only two patients. In the non-cerebral aspergillosis group (60 patients), PCR was positive in one patient, i.e. 98.3% specificity. In this particular population of high-risk patients with suspicion of cerebral aspergillosis, the disease incidence was 16.7%. Therefore, the positive and negative predictive values of PCR were 90% and 95.2%, respectively. CONCLUSION: The results of this study indicate that Aspergillus PCR in CSF is an interesting tool that may eliminate the need for cerebral biopsy in patients with suspected cerebral aspergillosis.

Analytical and Clinical Evaluation of the PathoNostics AsperGenius Assay for Detection of Invasive Aspergillosis and Resistance to Azole Antifungal Drugs Directly from Plasma Samples.

With the proposal to include Aspergillus PCR in the revised European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and National Institute of Allergy and Infectious Diseases Mycoses Study Group (EORTC/MSG) definitions for fungal disease, commercially manufactured assays may be required to provide standardization and accessibility. The PathoNostics AsperGenius assay represents one such test that has the ability to detect a range of Aspergillus species as well as azole resistance in Aspergillus fumigatus Its performance has been validated on bronchoalveolar lavage (BAL) fluid and serum specimens, but recent evidence suggests that testing of plasma may have enhanced sensitivity over that with serum. We decided to evaluate the analytical and clinical performances of the PathoNostics AsperGenius assay for testing of plasma. For the analytical evaluations, plasma was spiked with various concentrations of Aspergillus genomic DNA before extraction following international recommendations, using two automated platforms. For the clinical study, 211 samples from 10 proven/probable invasive aspergillosis (IA) and 2 possible IA cases and 27 controls were tested. The limits of detection for testing of DNA extracted using the bioMérieux EasyMag and Qiagen EZ1 extractors were 5 and 10 genomes/0.5-ml sample, respectively. In the clinical study, true positivity was significantly greater than false positivity (P < 0.0001). The sensitivity and specificity obtained using a single positive result as significant were 80% and 77.8%, respectively. If multiple samples were required to be positive, specificity was increased to 100%, albeit sensitivity was reduced to 50%. The AsperGenius assay provided good clinical performance, but the predicted improvement of testing with plasma was not seen, possibly as a result of target degradation attributed to sample storage. Prospective testing is required to determine the clinical utility of this assay, particularly for the diagnosis of azole-resistant disease.

Usefulness of Two Aspergillus PCR Assays and Aspergillus Galactomannan and ß-d-Glucan Testing of Bronchoalveolar Lavage Fluid for Diagnosis of Chronic Pulmonary Aspergillosis.

We evaluated the usefulness of an Aspergillus galactomannan (GM) test, a ß-d-glucan (ßDG) test, and two different Aspergillus PCR assays of bronchoalveolar lavage fluid (BALF) samples for the diagnosis of chronic pulmonary aspergillosis (CPA). BALF samples from 30 patients with and 120 patients without CPA were collected. We calculated the sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio for each test individually and in combination with other tests. The optical density index values, as determined by receiver operating characteristic analysis, for the diagnosis of CPA were 0.5 and 100 for GM and ßDG testing of BALF, respectively. The sensitivity and specificity of the GM test, ßDG test, and PCR assays 1 and 2 were 77.8% and 90.0%, 77.8% and 72.5%, 86.7% and 84.2%, and 66.7% and 94.2%, respectively. A comparison of the PCR assays showed that PCR assay 1 had a better sensitivity, a better negative predictive value, and a better negative likelihood ratio and PCR assay 2 had a better specificity, a better positive predictive value, and a better positive likelihood ratio. The combination of the GM and ßDG tests had the highest diagnostic odds ratio. The combination of the GM and ßDG tests on BALF was more useful than any single test for diagnosing CPA.

Determining the analytical specificity of PCR-based assays for the diagnosis of IA: What is Aspergillus?

A wide array of PCR tests has been developed to aid the diagnosis of invasive aspergillosis (IA), providing technical diversity but limiting standardisation and acceptance. Methodological recommendations for testing blood samples using PCR exist, based on achieving optimal assay sensitivity to help exclude IA. Conversely, when testing more invasive samples (BAL, biopsy, CSF) emphasis is placed on confirming disease, so analytical specificity is paramount. This multicenter study examined the analytical specificity of PCR methods for detecting IA by blind testing a panel of DNA extracted from a various fungal species to explore the range of Aspergillus species that could be detected, but also potential cross reactivity with other fungal species. Positivity rates were calculated and regression analysis was performed to determine any associations between technical specifications and performance. The accuracy of Aspergillus genus specific assays was 71.8%, significantly greater (P < .0001) than assays specific for individual Aspergillus species (47.2%). For genus specific assays the most often missed species were A. lentulus (25.0%), A. versicolor (24.1%), A. terreus (16.1%), A. flavus (15.2%), A. niger (13.4%), and A. fumigatus (6.2%). There was a significant positive association between accuracy and using an Aspergillus genus PCR assay targeting the rRNA genes (P = .0011). Conversely, there was a significant association between rRNA PCR targets and false positivity (P = .0032). To conclude current Aspergillus PCR assays are better suited for detecting A. fumigatus, with inferior detection of most other Aspergillus species. The use of an Aspergillus genus specific PCR assay targeting the rRNA genes is preferential.

Biomarker-based diagnostic work-up of invasive pulmonary aspergillosis in immunocompromised paediatric patients--is Aspergillus PCR appropriate?

Invasive aspergillosis (IA) is an important cause of morbidity and mortality in children and adults with haematologic malignancies or undergoing allogeneic haematopoietic stem cell transplantation, and early diagnosis and adequate antifungal treatment improve outcome. However, important differences exist between children and adults regarding epidemiology, underlying disease, and comorbidities, and the value of diagnostic tools to detect IA may also differ between these patient populations. Imaging studies are important to detect IA early, but typical findings of IA in chest computed tomography of adults are not detected in the majority of children. Whereas the value of the serum marker galactomannan seems to be comparable in children and adults, data on the performance of beta-d-glucan in children are too limited for firm conclusions. PCR-based assays are a promising diagnostic approach to rapidly and reliably detect and identify Aspergillus species in various clinical samples. However, as the majority of data on PCR-based approaches has been obtained in adult patients, the value of this method in paediatric patients has not been defined to date. The present review focuses on studies of PCR-based methods to diagnose IA in immunocompromised paediatric patients.

PCR Technology for Detection of Invasive Aspergillosis.

The application of molecular technologies to aid diagnosis and management of infectious diseases has had a major impact and many assays are in routine use. Diagnosis of aspergillosis has lagged behind. Lack of standardization and limited commercial interest have meant that PCR was not included in consensus diagnostic criteria for invasive fungal disease. In the last ten years careful evaluation and validation by the Aspergillus European PCR initiative with the development of standardized extraction, amplification and detection protocols for various specimen types, has provided the opportunity for clinical utility to be investigated. PCR has the potential to not only exclude a diagnosis of invasive aspergillosis but in combination with antigen testing may offer an approach for the early diagnosis and treatment of invasive aspergillosis in high-risk populations, with the added benefit of detection of genetic markers associated with antifungal resistance.

Performance of MycAssay Aspergillus DNA real-time PCR assay compared with the galactomannan detection assay for the diagnosis of invasive aspergillosis from serum samples.

Invasive aspergillosis (IA) is a major problem in the immunocompromised population, and its diagnosis is difficult due to the low sensitivity of available tests. Detection of Aspergillus nucleic acid by polymerase chain reaction (PCR) in serum samples is a promising diagnostic tool; however, use of multiple "in-house" methods precludes standardization. The first commercial PCR assay, MycAssay Aspergillus (Myconostica, Ltd), became available recently, and its performance in the diagnosis of IA was evaluated and compared with the galactomannan (GM) assay. Serum samples obtained from patients with hematological cancer were tested retrospectively with MycAssay Aspergillus PCR. Per-episode and per-test analyses were undertaken with 146 sera from 35 hematological patients. Sixteen patients had proven or probable IA and 19 had possible or no IA. In per-episode analysis, MycAssay Aspergillus had a sensitivity of 43.8% (95% confidence interval [CI], 19.8%-70.1%) and a specificity of 63.2% (95% CI, 38.4%-83.7%) for IA diagnosis. In per-test analyses, MycAssay Aspergillus had a lower specificity than the GM assay (83.3% vs. 93.1%, P = 0.04). The addition of PCR to routine clinical practice would have permitted the diagnosis of one additional probable IA in our cohort. Use of PCR instead of GM assay would have delayed the diagnosis in two cases. Aspergillus DNA detection by PCR with serum specimens using MycAssay showed a lower specificity than the GM assay and was associated with a low sensitivity for IA diagnosis. More studies are needed to determine the exact role of MycAssay in IA diagnosis in patients with hematological malignancy.

Clinical utility of Aspergillus galactomannan and PCR in bronchoalveolar lavage fluid for the diagnosis of invasive pulmonary aspergillosis in patients with haematological malignancies.

Interpretation of Aspergillus galactomannan (GM) and PCR results in bronchoalveolar lavage (BAL) fluid for the diagnosis of invasive pulmonary aspergillosis (IPA) in patients with haematological malignancies requires clarification. A total of 116 patients underwent BAL for investigation of new lung infiltrates: 40% were neutropenic, 68% and 36% were receiving mould-active antifungal agents and ß-lactam antibiotics. The diagnosis of proven IPA (n = 3), probable IPA (n = 15), and possible invasive fungal disease (IFD, n = 50) was made without inclusion of GM results. BAL GM (at cut-off of 0.8) had lower diagnostic sensitivity for IPA than PCR (61% versus 78%) but higher specificity (93% versus 79%). Both tests had excellent negative predictive values (85-90%), supporting their utility in excluding IPA. The use of BAL GM and PCR results increased the certainty of Aspergillus aetiology in 7 probable IPA cases where fungal hyphae were detected in respiratory samples by microscopy, and upgraded 24 patients from possible IFD to probable IPA. Use of BAL GM and PCR improves the diagnosis of IPA.