Early switch to oral antibiotic therapy in patients with low-risk neutropenic sepsis (EASI-SWITCH): a randomized non-inferiority trial.

OBJECTIVES: To determine whether early switch to oral antibiotic treatment in adults with neutropenic sepsis at low risk of complications is non-inferior to switching later. METHODS: This non-inferiority, parallel-group, randomized, open-label clinical trial enrolled UK adults hospitalized with neutropenic sepsis. Participants were randomly assigned to either switch to oral ciprofloxacin plus co-amoxiclav within 12-24 hours or to continue intravenous treatment for at least 48 hours. The primary outcome was a composite measure of treatment failure, 14 days after randomization. The non-inferiority margin was 15%. RESULTS: There were 129 participants from 16 centres and 125 were assessed for the primary outcome. Of these, 113 patients completed protocolized treatment and comprised the per-protocol population. In total, 9 (14.1%) of 64 patients in the standard care arm met the primary end point, compared with 15 (24.6%) of 61 in the early switch arm, giving a risk difference of 10.5% (1-sided 95% CI, -∞% to 22%; p 0.14). In the per-protocol population, 8 (13.3%) of the 60 patients in the standard care arm met the primary end point, compared with 9 (17%) of 53 in the intervention arm giving a risk difference of 3.7% (one-sided 95% CI, -∞% to 14.8%; p 0.59). Duration of hospital stay was shorter in the intervention arm (median 2 [inter-quartile range (IQR) 2-3] vs. 3 days [IQR 2-4]; p 0.002). DISCUSSION: Although non-inferiority of early oral switch was found in the per-protocol population, the intervention was not non-inferior in the intent-to-treat population.

An Overview of Systematic Reviews of Polymerase Chain Reaction (PCR) for the Diagnosis of Invasive Aspergillosis in Immunocompromised People: A Report of the Fungal PCR Initiative (FPCRI)-An ISHAM Working Group.

This overview of reviews (i.e., an umbrella review) is designed to reappraise the validity of systematic reviews (SRs) and meta-analyses related to the performance of Aspergillus PCR tests for the diagnosis of invasive aspergillosis in immunocompromised patients. The methodological quality of the SRs was assessed using the AMSTAR-2 checklist; the quality of the evidence (QOE) within each SR was appraised following the GRADE approach. Eight out of 12 SRs were evaluated for qualitative and quantitative assessment. Five SRs evaluated Aspergillus PCR on bronchoalveolar lavage fluid (BAL) and three on blood specimens. The eight SRs included 167 overlapping reports (59 evaluating PCR in blood specimens, and 108 in BAL), based on 107 individual primary studies (98 trials with a cohort design, and 19 with a case-control design). In BAL specimens, the mean sensitivity and specificity ranged from 0.57 to 0.91, and from 0.92 to 0.97, respectively (QOE: very low to low). In blood specimens (whole blood or serum), the mean sensitivity ranged from 0.57 to 0.84, and the mean specificity from 0.58 to 0.95 (QOE: low to moderate). Across studies, only a low proportion of AMSTAR-2 critical domains were unmet (1.8%), demonstrating a high quality of methodological assessment. Conclusions. Based on the overall methodological assessment of the reviews included, on average we can have high confidence in the quality of results generated by the SRs.

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.

The Presence of (1→3)-ß-D-Glucan as Prognostic Marker in Patients After Major Abdominal Surgery.

BACKGROUND: While the serological detection of (1→3)-ß-D-glucan (BDG) can indicate invasive fungal disease (IFD), false positivity occurs. Nevertheless, the presence of BDG can still be recognized by the host's innate immune system and persistent BDG antigenemia, in the absence of IFD, can result in deleterious proinflammatory immune responses. METHODS: During the XXX (INTENSE) study into the preemptive use of micafungin to prevent invasive candidiasis (IC) after abdominal surgery, the serum burden of BDG was determined to aid diagnosis of IC. Data from the INTENSE study were analyzed to determine whether BDG was associated with organ failure and patient mortality, while accounting for the influences of IC and antifungal therapy. RESULTS: A BDG concentration >100 pg/mL was associated with a significantly increased Sequential Organ Failure Assessment score (≤100 pg/mL: 2 vs >100 pg/mL: 5; P < .0001) and increased rates of mortality (≤100 pg/mL: 13.7% vs >100 pg/mL: 39.0%; P = .0002). Multiple (≥2) positive results >100 pg/mL or a BDG concentration increasing >100 pg/mL increased mortality (48.1%). The mortality rate in patients with IC and a BDG concentration >100 pg/mL and ≤100 pg/mL was 42.3% and 25.0%, respectively. The mortality rate in patients without IC but a BDG concentration >100 pg/mL was 37.3%. The use of micafungin did not affect the findings. CONCLUSIONS: The presence of persistent or increasing BDG in the patient's circulation is associated with significant morbidity and mortality after abdominal surgery, irrespective of IC. The potential lack of a specific therapeutic focus has consequences when trying to manage these patients, and when designing clinical trials involving patients where host-associated BDG concentrations may be elevated. CLINICAL TRIALS REGISTRATION: NCT01122368.

Early switch from intravenous to oral antibiotic therapy in patients with cancer who have low-risk neutropenic sepsis (the EASI-SWITCH trial): study protocol for a randomised controlled trial.

BACKGROUND: Neutropenic sepsis remains a common treatment complication for patients receiving systemic anti-cancer treatment. The UK National Institute for Health and Care Excellence have not recommended switching from empirical intravenous antibiotics to oral antibiotics within 48 h for patients assessed as low risk for septic complications because of uncertainty about whether this would achieve comparable outcomes to using intravenous antibiotics for longer. The UK National Institute for Health Research funded the EASI-SWITCH trial to tackle this uncertainty. METHODS: The trial is a pragmatic, randomised, non-inferiority trial that aims to establish the clinical and cost-effectiveness of early switching from intravenous to oral antibiotics in cancer patients with low-risk neutropenic sepsis. Patients ≥ 16 years, receiving systemic anti-cancer treatment (acute leukaemics/stem cell transplants excluded), with a temperature of > 38 °C, neutrophil count ≤ 1.0 × 109/L, MASCC (Multinational Association of Supportive Care in Cancer) score ≥ 21 and receiving IV piperacillin/tazobactam or meropenem for less than 24 h are eligible to participate. Patients are randomised 1:1 either (i) to switch to oral ciprofloxacin and co-amoxiclav within 12-24 h of commencing intravenous antibiotics, completing at least 5 days total antibiotics (intervention), or (ii) to continue intravenous antibiotics for at least 48 h, with ongoing antibiotics being continued at the physician's discretion (control). Patients are discharged home when their physician deems it appropriate. The primary outcome measure is a composite of treatment failures as assessed at day 14. The criteria for treatment failure include fever persistence or recurrence 72 h after starting intravenous antibiotics, escalation from protocolised antibiotics, hospital readmission related to infection/antibiotics, critical care support or death. Based on a 15% treatment failure rate in the control group and a 15% non-inferiority margin, the recruitment target is 230 patients. DISCUSSION: If the trial demonstrates non-inferiority of early switching to oral antibiotics, with potential benefits for patient quality of life and resource savings, this finding will have significant implications for the routine clinical management of those with low-risk neutropenic sepsis. TRIAL REGISTRATION: ISRCTN: 84288963. Registered on the 1 July 2015. https://doi.org/10.1186/ISRCTN84288963. EudraCT: 2015-002830-35.

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.

An evaluation of the performance of the Dynamiker® Fungus (1-3)-ß-D-Glucan Assay to assist in the diagnosis of Pneumocystis pneumonia.

The Dynamiker® Fungus (1-3)-ß-D-Glucan Assay (D-BDG) has recently become available in the Western Hemisphere for the diagnosis of invasive fungal disease (IFD). Evaluations of its performance for Pneumocystis pneumonia (PcP) are limited. A retrospective evaluation of D-BDG diagnosis of PcP was performed (23 PcP cases and 23 controls). Sensitivity and specificity were 87% and 70%, respectively, reducing the positivity threshold to 45 pg/ml increased sensitivity (96%), whereas a threshold of 300 pg/ml increased specificity (96%). The performance of D-BDG for the detection of PcP is comparable to other IFD, but sensitivity is below that required to confidently exclude PcP.

Diagnosis of aspergillosis by PCR: Clinical considerations and technical tips.

Standardization of Aspergillus polymerase chain reaction (PCR) protocols has progressed, and analytical validity of blood-based assays has been formally established. It remains necessary to consider how the tests can be used in practice to maximize clinical utility. To determine the optimal diagnostic strategies and influence on patient management, several factors require consideration, including the patient population, incidence of invasive aspergillosis (and other fungal disease), and the local antifungal prescribing policy. Technical issues such as specimen type, ease of sampling, frequency of testing, access to testing centers, and time to reporting will also influence the use of PCR in clinical practice. Interpretation of all diagnostic tests is dependent on the clinical context and molecular assays are no exception, but with the proposal to incorporate Aspergillus PCR into the second revision of the consensus guidelines for defining invasive fungal disease the acceptance and understanding of molecular tests should improve.

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.

Diagnosis and management of Pneumocystis jirovecii infection.

INTRODUCTION: Pneumocystis jirovecii is a ubiquitous fungus, which causes pneumonia in humans. Diagnosis was hampered by the inability to culture the organism, and based on microscopic examination of respiratory samples or clinical presentation. New assays can assist in the diagnosis and even aid with the emergence of resistant infections. Areas covered: This manuscript will provide background information on Pneumocystis pneumonia (PcP). Diagnosis, from radiological to non-microbiological (e.g. Lactate dehydrogenase) and microbiological investigations (Microscopy, PCR, ß-D-Glucan) will be discussed. Recommendations on prophylactic and therapeutic management will be covered. Expert commentary: PcP diagnosis using microscopy is far from optimal and false negatives will occur. With an incidence of 1% or less, the pre-test probability of not having PcP is 99% and testing is suited to excluding disease. Microscopy provides a high degree of diagnostic confidence but it is not infallible, and its lower sensitivity limits its application. Newer diagnostics (PCR, ß-D-Glucan) can aid management and improve performance when testing less invasive specimens, such as upper respiratory samples or blood, alleviating clinical pressure. Combination testing may allow PcP to be both diagnosed and excluded, and molecular testing can assist in the detection of emerging resistant PcP.

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.

An evaluation of the performance of the Dynamiker® Fungus (1-3)-ß-D-Glucan Assay to assist in the diagnosis of invasive aspergillosis, invasive candidiasis and Pneumocystis pneumonia.

Invasive fungal disease (IFD) can be caused by a range of pathogens. Conventional diagnosis has the capacity to detect most causes of IFD, but poor performance limits impact. The introduction of non-culture diagnostics, including the detection of (1-3)-ß-D-Glucan (BDG), has shown promising performance for the detection of IFD in variety of clinical settings. Recently, the Dynamiker® Fungus (1-3)-ß-D-Glucan assay (D-BDG) was released as an IFD diagnostic test. This article describes an evaluation of the D-BDG assay for the diagnosis of invasive aspergillosis (IA), invasive candidiasis (IC) and Pneumocystis pneumonia (PCP) across several high-risk patient cohorts and provides comparative data with the Associates of Cape Cod Fungitell® and BioRad Platelia™ Aspergillus Ag (GM) assays. There were 163 serum samples from 121 patients tested, from 21 probable IA cases, 28 proven IC cases, six probable PCP cases, one probable IFD case, 14 possible IFD cases and 64 control patients. For proven/probable IFD the mean BDG concentration was 209pg/ml, significantly greater than the control population (73pg/ml; P: <.0001). The sensitivity, specificity, and diagnostic odds ratio for proven/probable IFD was 81.4%, 78.1%, and 15.5, respectively. Significant BDG false positivity (9/13) was associated post abdominal surgery. D-BDG showed fair and good agreement with the Fungitell®, and GM assays, respectively. In conclusion, the D-BDG provides a useful adjunct test to aid the diagnosis of IFD, with technical flexibility that will assist laboratories processing low sample numbers. Further, large scale, prospective evaluation is required to confirm the clinical validity and determine clinical utility.

Respiratory pathogen colonization of dental plaque, the lower airways, and endotracheal tube biofilms during mechanical ventilation.

PURPOSE: In mechanically ventilated patients, the endotracheal tube is an essential interface between the patient and ventilator, but inadvertently, it also facilitates the development of ventilator-associated pneumonia (VAP) by subverting pulmonary host defenses. A number of investigations suggest that bacteria colonizing the oral cavity may be important in the etiology of VAP. The present study evaluated microbial changes that occurred in dental plaque and lower airways of 107 critically ill mechanically ventilated patients. MATERIALS AND METHODS: Dental plaque and lower airways fluid was collected during the course of mechanical ventilation, with additional samples of dental plaque obtained during the entirety of patients' hospital stay. RESULTS: A "microbial shift" occurred in dental plaque, with colonization by potential VAP pathogens, namely, Staphylococcus aureus and Pseudomonas aeruginosa in 35 patients. Post-extubation analyses revealed that 70% and 55% of patients whose dental plaque included S aureus and P aeruginosa, respectively, reverted back to having a predominantly normal oral microbiota. Respiratory pathogens were also isolated from the lower airways and within the endotracheal tube biofilms. CONCLUSIONS: To the best of our knowledge, this is the largest study to date exploring oral microbial changes during both mechanical ventilation and after recovery from critical illness. Based on these findings, it was apparent that during mechanical ventilation, dental plaque represents a source of potential VAP pathogens.

Issues in antifungal stewardship: an opportunity that should not be lost.

Many countries have observed an increase in the incidence of invasive fungal infections (IFIs) over the past two decades with emergence of new risk factors and isolation of new fungal pathogens. Early diagnosis and appropriate antifungal treatment remain the cornerstones of successful outcomes. However, due to non-specific clinical presentations and limited availability of rapid diagnostic tests, in more than half of cases antifungal treatment is inappropriate. As a result, the emergence of antifungal resistance both in yeasts and mycelial fungi is becoming increasingly common. The Delhi Chapter of the Indian Association of Medical Microbiologists (IAMM-DC) organized a 1 day workshop in collaboration with BSAC on 10 December 2015 in New Delhi to design a road map towards the development of a robust antifungal stewardship programme in the context of conditions in India. The workshop aimed at developing a road map for optimizing better outcomes in patients with IFIs while minimizing unintended consequences of antifungal use, ultimately leading to reduced healthcare costs and prevention development of resistance to antifungals. The workshop was a conclave of all stakeholders, eminent experts from India and the UK, including clinical microbiologists, critical care specialists and infectious disease physicians. Various issues in managing IFIs were discussed, including epidemiology, diagnostic and therapeutic algorithms in different healthcare settings. At the end of the deliberations, a consensus opinion and key messages were formulated, outlining a step-by-step approach to tackling the growing incidence of IFIs and antifungal resistance, particularly in the Indian scenario.

Isolation of Nucleic Acids for Fungal Diagnosis.

PCR can aid in the diagnosis of invasive fungal disease (IFD). While the large number of "in-house" methodologies drives technological diversity, providing robustness, they make it difficult to identify optimal strategies, limiting standardization, and widespread acceptance. No matter how efficient, PCR utility will be limited by the quality of extracted nucleic acid. This chapter highlights benefits and limitations affecting the nucleic acid extraction process, before focusing on recent recommendations that through multicenter evaluation have provided optimal and standardized methodology.

Predicting invasive fungal disease due to Candida species in non-neutropenic, critically ill, adult patients in United Kingdom critical care units.

BACKGROUND: Given the predominance of invasive fungal disease (IFD) amongst the non-immunocompromised adult critically ill population, the potential benefit of antifungal prophylaxis and the lack of generalisable tools to identify high risk patients, the aim of the current study was to describe the epidemiology of IFD in UK critical care units, and to develop and validate a clinical risk prediction tool to identify non-neutropenic, critically ill adult patients at high risk of IFD who would benefit from antifungal prophylaxis. METHODS: Data on risk factors for, and outcomes from, IFD were collected for consecutive admissions to adult, general critical care units in the UK participating in the Fungal Infection Risk Evaluation (FIRE) Study. Three risk prediction models were developed to model the risk of subsequent Candida IFD based on information available at three time points: admission to the critical care unit, at the end of 24 h and at the end of calendar day 3 of the critical care unit stay. The final model at each time point was evaluated in the three external validation samples. RESULTS: Between July 2009 and April 2011, 60,778 admissions from 96 critical care units were recruited. In total, 359 admissions (0.6 %) were admitted with, or developed, Candida IFD (66 % Candida albicans). At the rate of candidaemia of 3.3 per 1000 admissions, blood was the most common Candida IFD infection site. Of the initial 46 potential variables, the final admission model and the 24-h model both contained seven variables while the end of calendar day 3 model contained five variables. The end of calendar day 3 model performed the best with a c index of 0.709 in the full validation sample. CONCLUSIONS: Incidence of Candida IFD in UK critical care units in this study was consistent with reports from other European epidemiological studies, but lower than that suggested by previous hospital-wide surveillance in the UK during the 1990s. Risk modeling using classical statistical methods produced relatively simple risk models, and associated clinical decision rules, that provided acceptable discrimination for identifying patients at 'high risk' of Candida IFD. TRIAL REGISTRATION: The FIRE Study was reviewed and approved by the Bolton NHS Research Ethics Committee (reference: 08/H1009/85), the Scotland A Research Ethics Committee (reference: 09/MRE00/76) and the National Information Governance Board (approval number: PIAG 2-10(f)/2005).

Comparison of Nonculture Blood-Based Tests for Diagnosing Invasive Aspergillosis in an Animal Model.

The EuropeanAspergillusPCR Initiative (EAPCRI) has provided recommendations for the PCR testing of whole blood (WB) and serum/plasma. It is important to test these recommended protocols on nonsimulated "in vivo" specimens before full clinical evaluation. The testing of an animal model of invasive aspergillosis (IA) overcomes the low incidence of disease and provides experimental design and control that is not possible in the clinical setting. Inadequate performance of the recommended protocols at this stage would require reassessment of methods before clinical trials are performed and utility assessed. The manuscript describes the performance of EAPCRI protocols in an animal model of invasive aspergillosis. Blood samples taken from a guinea pig model of IA were used for WB and serum PCR. Galactomannan and ß-d-glucan detection were evaluated, with particular focus on the timing of positivity and on the interpretation of combination testing. The overall sensitivities for WB PCR, serum PCR, galactomannan, and ß-d-glucan were 73%, 65%, 68%, and 46%, respectively. The corresponding specificities were 92%, 79%, 80%, and 100%, respectively. PCR provided the earliest indicator of IA, and increasing galactomannan and ß-d-glucan values were indicators of disease progression. The combination of WB PCR with galactomannan and ß-d-glucan proved optimal (area under the curve [AUC], 0.95), and IA was confidently diagnosed or excluded. The EAPRCI-recommended PCR protocols provide performance comparable to commercial antigen tests, and clinical trials are warranted. By combining multiple tests, IA can be excluded or confirmed, highlighting the need for a combined diagnostic strategy. However, this approach must be balanced against the practicality and cost of using multiple tests.

Comparison of Performance Characteristics of Aspergillus PCR in Testing a Range of Blood-Based Samples in Accordance with International Methodological Recommendations.

Standardized methodologies for the molecular detection of invasive aspergillosis (IA) have been established by the European Aspergillus PCR Initiative for the testing of whole blood, serum, and plasma. While some comparison of the performance of Aspergillus PCR when testing these different sample types has been performed, no single study has evaluated all three using the recommended protocols. Standardized Aspergillus PCR was performed on 423 whole-blood pellets (WBP), 583 plasma samples, and 419 serum samples obtained from hematology patients according to the recommendations. This analysis formed a bicenter retrospective anonymous case-control study, with diagnosis according to 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) consensus definitions (11 probable cases and 36 controls). Values for clinical performance using individual and combined samples were calculated. For all samples, PCR positivity was significantly associated with cases of IA (for plasma, P = 0.0019; for serum, P = 0.0049; and for WBP, P = 0.0089). Plasma PCR generated the highest sensitivity (91%); the sensitivities for serum and WBP PCR were 80% and 55%, respectively. The highest specificity was achieved when testing WBP (96%), which was significantly superior to the specificities achieved when testing serum (69%, P = 0.0238) and plasma (53%, P = 0.0002). No cases were PCR negative in all specimen types, and no controls were PCR positive in all specimens. This study confirms that Aspergillus PCR testing of plasma provides robust performance while utilizing commercial automated DNA extraction processes. Combining PCR testing of different blood fractions allows IA to be both confidently diagnosed and excluded. A requirement for multiple PCR-positive plasma samples provides similar diagnostic utility and is technically less demanding. Time to diagnosis may be enhanced by testing multiple contemporaneously obtained sample types.

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.