Performance of galactomannan, beta-d-glucan, Aspergillus lateral-flow device, conventional culture, and PCR tests with bronchoalveolar lavage fluid for diagnosis of invasive pulmonary aspergillosis

Galactomannan testing and Aspergillus PCR in same-day bronchoalveolar lavage and blood samples for diagnosis of invasive aspergillosis

In recent years galactomannan antigen testing (GM) and also Aspergillus PCR have become increasingly important for diagnosis of invasive aspergillosis (IA). Whether or not these tests need to be performed with bronchoalveolar lavage fluid (BALF; i.e., primary site of infection), or testing of blood samples is sufficient, remains, however, a matter of debate. We evaluated the diagnostic performance of GM ELISA, and Aspergillus PCR by using BALF samples and blood samples obtained at the same day from a total of 53 immunocompromised patients (16 with probable/proven IA and 37 with no evidence of IA according to the revised EORTC/MSG criteria; 38 patients with hematological malignancies were prospectively enrolled at the Medical University of Graz, Austria, 15 patients with mixed underlying diseases at the Mannheim University Hospital). Patients with possible IA were excluded from this analysis. A total of 34/53 (64%) of all patients and 12/16 (75%) of patients with probable/proven IA received mold-active antifungal prophylaxis/therapy at the time of the BALF procedure. Sensitivities of GM and Aspergillus PCR were 38% and 44% in BALF, and 31% and 0% in blood, respectively. Best sensitivity (75%) for detecting proven/probable IA was achieved when BALF Aspergillus PCR, BALF GM (>1.0 ODI), BALF-culture and serum-GM (>0.5 ODI) were combined (specificity 95%). In conclusion, sensitivities of the evaluated diagnostic tests-when interpreted on their own-were low in BALF and even lower in blood, sensitivities increased markedly when diagnostic tests were combined.

Use of (1→3)-β-d-glucan for diagnosis and management of invasive mycoses in HIV-infected patients

People living with HIV (PLHIV) are highly vulnerable to invasive fungal infections (IFIs) due to their immune dysfunction. Diagnosis and treatment of IFIs remain challenging due to the requirement of deep tissue sampling to visualise and culture fungi before initiating treatment. Such techniques are less practical in resource‐limited settings due to their cost and requirement of relatively invasive procedures. Hence, identification of surrogate markers for the early diagnosis and therapeutic monitoring of IFIs is required. Recent studies have shown that (1→3)‐β‐d‐glucan (BDG), a major fungal cell wall antigen, represents a promising soluble marker for the presumptive diagnosis and therapeutic monitoring of IFIs in HIV‐infected patients. Herein, we review findings on the merits of BDG assays in the diagnosis of IFIs and monitoring of antifungal therapies for PLHIV. Conversely to other types of immunocompromised patients, HIV infection is associated with gut damage and subsequent bacterial and fungal translocation leading to elevated BDG plasma levels.

Detection of invasive pulmonary aspergillosis in critically ill patients by combined use of conventional culture, galactomannan, 1-3-beta-D-glucan and Aspergillus specific nested polymerase chain reaction in a prospective pilot study

Invasive pulmonary aspergillosis (IPA) is an emerging and life-threatening infectious disease in patients admitted to the intensive care unit (ICU). Most diagnostic studies are conducted in hematological patients and results cannot readily be transferred to ICU patients lacking classical host factors. In a multicenter, prospective clinical trial including 44 ICU patients, hematological (n = 14) and non-hematological patients (n = 30), concurrent serum and bronchoalveolar lavage (BAL) samples were analyzed by conventional culture, galactomannan (GM), 1-3-beta-D-glucan (BDG) as well as an Aspergillus specific nested polymerase chain reaction (PCR). Nine patients (20%) had putative IPA according to AspICU classification. GM and PCR showed superior performance in BAL with sensitivity/specificity of 56%/94% and 44%/94% compared to 33%/97% and 11%/94% in serum. Despite better sensitivity of 89%, BDG showed poor specificity of only 31% (BAL) and 26% (serum). Combination of GM and PCR (BAL) with BDG (serum) resulted in 100% sensitivity, but also reduced specificity to 23%. Whereas mean GM levels were significantly higher in hematological patients BDG and PCR did not differ between hematological and non-hematological patients. Under present clinical conditions test combinations integrating both BAL and blood samples are advantageous. BDG might best serve as possible indicator for ruling out IPA.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01695499. First posted: September 28, 2012, last update posted: May 8, 2017.

The spectrum of pulmonary aspergillosis

Notable progress has been made in the past years in the classification, diagnosis and treatment of pulmonary aspergillosis. New criteria were proposed by the Working Group of the International Society for Human and Animal Mycology (ISHAM) for the diagnosis of allergic bronchopulmonary aspergillosis (ABPA). The latest classification of chronic pulmonary aspergillosis (CPA) suggested by the European Society for Clinical Microbiology and Infectious Diseases (ESCMID) has become widely accepted among clinicians. Subacute invasive pulmonary aspergillosis is now considered a type of CPA, yet it is still diagnosed and treated similarly to invasive pulmonary aspergillosis (IPA). Isavuconazole, an extended-spectrum triazole, has recently been approved by the Food and Drug Administration (FDA) and the European Medicines Agency (EMA) for the treatment of IPA. The most recent Infectious Diseases Society of America (IDSA) guidelines strongly recommend reducing mold exposure to patients at high risk for pulmonary aspergillosis. The excessive relapse rate following discontinuation of therapy remains a common reality to all forms of this semi-continuous spectrum of diseases. This highlights the need to continuously reassess patients and individualize therapy accordingly. Thus far, the duration of therapy and the frequency of follow-up have to be well characterized.

Diagnosis of invasive aspergillosis in hematological malignancy patients: Performance of cytokines, Asp LFD, and Aspergillus PCR in same day blood and bronchoalveolar lavage samples

BACKGROUND

Aspergillus spp. induce elevated levels of several cytokines. It remains unknown whether these cytokines hold value for clinical routine and enhance diagnostic performances of established and novel biomarkers/tests for invasive aspergillosis (IA).

METHODS

This cohort study included 106 prospectively enrolled (2014-2017) adult cases with underlying hematological malignancies and suspected pulmonary infection undergoing bronchoscopy. Serum samples were collected within 24 hours of bronchoalveolar lavage fluid (BALF) sampling. Both, serum and BALF samples were used to evaluate diagnostic performances of the Aspergillus-specific lateral-flow device test (LFD), Aspergillus PCR, β-D-glucan, and cytokines that have shown significant associations with IA before.

RESULTS

Among 106 cases, 11 had probable IA, and 32 possible IA; 80% received mold-active antifungals at the time of sampling. Diagnostic tests and biomarkers showed better performance in BALF versus blood, with the exception of serum interleukin (IL)-8 which was the most reliable blood biomarker. Combinations of serum IL-8 with either BALF LFD (sensitivity 100%, specificity 94%) or BALF PCR (sensitivity 91%, specificity 97%) showed promise for differentiating probable IA from no IA.

CONCLUSIONS

High serum IL-8 levels were highly specific, and when combined with either the BALF Aspergillus-specific LFD, or BALF Aspergillus PCR also highly sensitive for diagnosis of IA.

Diagnosis of invasive mold diseases in patients with hematological malignancies using Aspergillus, Mucorales, and panfungal PCR in BAL

BACKGROUND

Accurate diagnosis of invasive mold diseases (IMD) remains challenging. Here, the performance of panfungal PCR, Aspergillus and MucoralesPCR in bronchoalveolar lavage (BAL) was evaluated.

METHODS

We conducted a single-center study including 167 hematologic patients at risk for IMD with BAL performed 2011-2014. Diagnostic performance of single tests (Aspergillus-, Mucorales-, and panfungal PCR, galactomannan (GM)≥0.5 and ≥1, culture/cytology) or in combination was calculated for predicting IMD comparing proven/probable or proven/probable/possible IMD vs no IMD, respectively.

RESULTS

IMD was classified as proven (n = 6), probable (n = 31), possible (n = 29) and no IMD (n = 101) according to EORTC/MSG criteria. GM ≥ 0.5 in BAL showed the highest sensitivity with 81% for diagnosing IMD whereas the other tests only 5%-35%. By contrast, specificity was highest for panfungal PCR with 99% and GM ≥ 1, Mucorales and AspergillusPCR reached specificity ≥91%. When combining the tests, GM ≥ 0.5 and panfungal PCR show a sensitivity and specificity of 87% and 78% for IMD or with AspergillusPCR a sensitivity and specificity of 88% and 72% for invasive pulmonary aspergillosis, respectively. Including possible IMD patients did not improve the sensitivity of PCRs. In probable/proven IMD patients, the addition of panfungal PCR resulted further in detection of Fusarium species and Alternaria species, and the MucoralesPCR was positive in 2 probable IMD cases.

CONCLUSION

This study illustrates that the diagnosis of IMD is still very problematic and lacks objectivity. Together with GM in BAL, the PCRs may prove an addition to the current available diagnostic armamentarium in IMD because of their ability to identify molds on a species level.

The evolving landscape of new diagnostic tests for invasive aspergillosis in hematology patients: strengths and weaknesses

PURPOSE OF REVIEW

The diagnosis of invasive aspergillosis in hematologic patients is a complex composite of clinical preconditions and features, imaging findings, biomarker combinations from appropriate clinical samples and microbiological and/or histological findings.

RECENT FINDINGS

Recent developments in the evolving landscape of diagnostic tests for invasive aspergillosis in adult hematology patients are highlighted.

SUMMARY

Novel approaches and tools are currently under development. Focusing optimized diagnostic performance, in particular the combination of biomarkers from appropriate clinical samples, improved diagnostic performance distinctly.

Molecular detection of fungal pathogens in clinical specimens by 18S rDNA high-throughput screening in comparison to ITS PCR and culture

The rising incidence of invasive fungal infections and the expanding spectrum of fungal pathogens makes early and accurate identification of the causative pathogen a daunting task. Diagnostics using molecular markers enable rapid identification of fungi, offer new insights into infectious disease dynamics, and open new possibilities for infectious disease control and prevention. We performed a retrospective study using clinical specimens (N = 233) from patients with suspected fungal infection previously subjected to culture and/or internal transcribed spacer (ITS) PCR. We used these specimens to evaluate a high-throughput screening method for fungal detection using automated DNA extraction (QIASymphony), fungal ribosomal small subunit (18S) rDNA RT-PCR and amplicon sequencing. Fungal sequences were compared with sequences from the curated, commercially available SmartGene IDNS database for pathogen identification. Concordance between 18S rDNA RT-PCR and culture results was 91%, and congruence between 18S rDNA RT-PCR and ITS PCR results was 94%. In addition, 18S rDNA RT-PCR and Sanger sequencing detected fungal pathogens in culture negative (N = 13) and ITS PCR negative specimens (N = 12) from patients with a clinically confirmed fungal infection. Our results support the use of the 18S rDNA RT-PCR diagnostic workflow for rapid and accurate identification of fungal pathogens in clinical specimens.

Diagnosis and management of Aspergillus diseases: executive summary of the 2017 ESCMID-ECMM-ERS guideline

The European Society for Clinical Microbiology and Infectious Diseases, the European Confederation of Medical Mycology and the European Respiratory Society Joint Clinical Guidelines focus on diagnosis and management of aspergillosis. Of the numerous recommendations, a few are summarized here. Chest computed tomography as well as bronchoscopy with bronchoalveolar lavage (BAL) in patients with suspicion of pulmonary invasive aspergillosis (IA) are strongly recommended. For diagnosis, direct microscopy, preferably using optical brighteners, histopathology and culture are strongly recommended. Serum and BAL galactomannan measures are recommended as markers for the diagnosis of IA. PCR should be considered in conjunction with other diagnostic tests. Pathogen identification to species complex level is strongly recommended for all clinically relevant Aspergillus isolates; antifungal susceptibility testing should be performed in patients with invasive disease in regions with resistance found in contemporary surveillance programmes. Isavuconazole and voriconazole are the preferred agents for first-line treatment of pulmonary IA, whereas liposomal amphotericin B is moderately supported. Combinations of antifungals as primary treatment options are not recommended. Therapeutic drug monitoring is strongly recommended for patients receiving posaconazole suspension or any form of voriconazole for IA treatment, and in refractory disease, where a personalized approach considering reversal of predisposing factors, switching drug class and surgical intervention is also strongly recommended. Primary prophylaxis with posaconazole is strongly recommended in patients with acute myelogenous leukaemia or myelodysplastic syndrome receiving induction chemotherapy. Secondary prophylaxis is strongly recommended in high-risk patients. We strongly recommend treatment duration based on clinical improvement, degree of immunosuppression and response on imaging.

Spotlight on isavuconazole in the treatment of invasive aspergillosis and mucormycosis: design, development, and place in therapy

In recent decades, important advances have been made in the diagnosis and treatment of invasive aspergillosis (IA) and mucormycosis. One of these advances has been the introduction of isavuconazole, a second-generation broad spectrum triazole with a favorable pharmacokinetic and safety profile and few drug–drug interactions. Phase III trials in patients with IA and mucormycosis demonstrated that isavuconazole has similar efficacy to voriconazole for the treatment of IA (SECURE trial) and liposomal amphotericin B for the treatment of mucormycosis (VITAL trial with subsequent case–control analysis) and a favorable safety profile with significantly fewer ocular, hepatobiliary, and skin and soft tissue adverse events compared to voriconazole. As a result, recent IA guidelines recommend isavuconazole (together with voriconazole) as gold standard treatment for IA in patients with underlying hematological malignancies. In contrast to liposomal amphotericin B, isavuconazole can be safely administered in patients with reduced renal function and is frequently used for the treatment of mucormycosis in patients with reduced renal function. Updated guidelines on mucormycosis are needed to reflect the current evidence and give guidance on the use of isavuconazole for mucormycosis. Studies are needed to evaluate the role of isavuconazole for 1) anti-mold prophylaxis in high-risk patients, 2) salvage treatment for IA and mucormycosis, and 3) treatment for other mold infections such as Scedosporium apiospermum.

Evaluation of the new AspID polymerase chain reaction assay for detection of Aspergillus species: A pilot study

The newly developed AspID PCR assay for detection of Aspergillus spp. was evaluated with an interlaboratory quality control programme panel and human bronchoalveolar lavage fluid (BALF) samples. With the quality control programme, 8 out of 9 panel members were correctly identified. With the clinical study, 36 BALF samples that had been obtained from 18 patients with invasive pulmonary aspergillosis (IPA) and 18 without IPA were investigated. Sensitivity, specificity, positive and negative likelihood ratio for the AspID assay were 94.1% (95% CI 73.3-99.9), 76.5% (95% CI 50.1-93.2), 4 (95% CI 1.7-9.5) and 0.1 (95% CI 0.01-0.5) respectively.

Evaluation of Two Commercial Real-Time PCR Kits for Aspergillus DNA Detection in Bronchoalveolar Lavage Fluid in Patients with Invasive Pulmonary Aspergillosis

Invasive pulmonary aspergillosis (IPA) is a common complication of immunosuppression. Rapid diagnosis using molecular techniques is essential to improve patient survival. PCR techniques are promising in enhancing Aspergillus detection in blood and respiratory samples. We evaluate for the first time the performances of two commercial real-time PCR kits, the A. fumigatus Bio-Evolution and the MycoGENIE A. fumigatus for the detection of A. fumigatus DNA in bronchoalveolar lavage (BAL) from patients with and without IPA. Seventy-three BAL samples were included. Thirty-one of them corresponded to patients with probable IPA, 11 to patients with possible IPA, and 31 to patients without aspergillosis, according to the 2008 European Organization for Research and Treatment of Cancer/Mycoses Study Group criteria. In the probable IPA group, A. fumigatus Bio-Evolution and the MycoGENIE A. fumigatus real-time PCR kits showed a specificity of 100% and a sensitivity of 81% and 71%, respectively. The A. fumigatus Bio-Evolution detected Aspergillus DNA in the 14 BAL samples with a positive Aspergillus culture result, whereas the MycoGENIE A. fumigatus PCR result was positive only for 12. In the possible IPA group, there were no positive real-time PCR or positive Aspergillus culture results. For the patients without aspergillosis, no positive result was observed for real-time PCR kit, despite the presence of various other non-Aspergillus pathogens in this group. Our study demonstrates an excellent specificity and a good sensitivity of A. fumigatus DNA detection in BAL samples with both kits.

Real-world challenges and unmet needs in the diagnosis and treatment of suspected invasive pulmonary aspergillosis in patients with haematological diseases: An illustrative case study

Recent years have seen important advances in the diagnosis of invasive pulmonary aspergillosis (IPA), complemented by the introduction of new therapies. Despite this, IPA remains a major cause of infection-related mortality in patients with haematological diseases. There are two main reasons for this. First, diagnosis of IPA remains a challenge, since risk factors and the clinical, radiological and mycological presentations vary not only by fungal disease stage, but also by patient group (eg neutropenic vs non-neutropenic patients). Diagnosis is particularly challenging in patients receiving mould-active prophylactic or empirical treatment, which reduces the sensitivity of all diagnostic tests for IPA. Second, treatment of IPA is complex due to unpredictable pharmacokinetic profiles of antifungal agents, small therapeutic window in terms of exposure and adverse events, and multiple drug-drug interactions through the CYP450 system. Here we report a case of a 23-year-old male with severe aplastic anaemia and subpleural nodules. Diagnostic tests for IPA obtained during ongoing mould-active empirical treatment were negative. Intravenous voriconazole was stopped after visual disturbances and hallucinations. The patient then had an anaphylactic reaction to liposomal amphotericin B and was switched to intravenous posaconazole, which had to be discontinued due to a significant increase in transaminase levels. He was treated with oral isavuconazole with reduced dosage, triggered by increasing transaminases under the standard dosage. Even under reduced dosage, blood concentrations of isavuconazole were high and treatment was successful. The case illustrates real-world challenges and unmet needs in the diagnosis and treatment of IPA in patients with haematological diseases.

Use of 1,3-β-D-glucan in invasive fungal diseases in hematology patients

INTRODUCTION

Invasive fungal diseases (IFD) remain a leading cause of morbidity and mortality in hematology patients. Within a diagnostic-driven approach, the use of the serum (1,3)-ß-D-glucan (BDG) test represents a valid tool for the early diagnosis and treatment of IFD. Areas covered: The available literature on the use of BDG in hematology patients was systematically retrieved. Then, it was reviewed and discussed, to identify key issues pertaining to a clinically-oriented narrative presentation of the topic. Expert commentary: The use of BDG in hematology patients at risk for invasive aspergillosis (IA) is secondary to the use of galactomannan. However, since BDG is not specific for IA, it offers an advantage of diagnosing also other IFD, such as candidiasis and pneumocystosis. The limitations of BDG include high costs and lower sensitivity in hematology patients compared to other cohorts. The risk of false positive results is possibly lower in real life than in theory, since glucan-free equipment is available and modern dialysis membranes and blood products usually do not release BDG. Thus, in experienced hands and selected clinical situations, BDG is a useful diagnostic tool, particularly due to short turnover time to results and versatility in diagnosing different IFD.

Galactomannan in Bronchoalveolar Lavage Fluid for Diagnosis of Invasive Pulmonary Aspergillosis with Nonneutropenic Patients

Background

We evaluated the utility of galactomannan (GM) in bronchoalveolar lavage fluid (BALF) for the diagnosis of invasive pulmonary aspergillosis (IPA) in nonneutropenic patients.

Methods

A total of 183 patients were included in the final analysis. Bronchoscopies and the detection of GM in BALF were all performed on them.

Results

Ten cases of IPA were diagnosed. ROC data demonstrated that, for diagnosing IPA, an optimal cutoff value for GM in BALF of 0.76 yielded a sensitivity of 100.0% and a specificity of 76.2%. Symptoms and radiological findings had no significant difference between proven or probable IPA group and non-IPA group. In our case-control analysis, although nine patients with false-positive results received treatment with Piperacillin/tazobactam, there was no significant difference between case and control group.

Conclusions

BALF GM detection is a valuable adjunctive diagnostic tool. Our retrospective study suggests that the optimal value of GM detection in BALF is 0.76 in nonneutropenic patients.

Clinical evaluation of the newly formatted lateral-flow device for invasive pulmonary aspergillosis

The study evaluated the newly formatted Aspergillus-specific lateral-flow-device (LFD), and compared its performance to the original prototype "old" LFD test using BALF samples from 28 patients (14 patients with probable/proven invasive pulmonary aspergillosis [IPA] and 14 patients with no evidence for IPA). A total of 10/14 (71%) of BALF samples from patients with probable/proven IPA resulted positive with the new LFD, including 8/9 with true-positive and 2/5 with false-negative results with the old LFD. All 14 samples from patients without IPA resulted negative with the new LFD; specificity of the new LFD was significantly improved compared to the old LFD.

Testing the performance of a prototype lateral flow device using bronchoalveolar lavage fluid for the diagnosis of invasive pulmonary aspergillosis in high-risk patients

The diagnosis of invasive pulmonary aspergillosis (IPA) increasingly relies on non-culture-based biomarkers in bronchoalveolar lavage (BAL) fluid. The Aspergillus lateral flow device (LFD) is a rapid immunoassay that uses a novel Aspergillus monoclonal antibody to gain specificity. The objective of the study is to compare specificity and sensitivity of the prototype LFD and the galactomannan (GM) enzyme immunoassay in BAL fluid in high-risk patients. A total of 114 BAL samples from 106 patients at high risk for IPA were studied: 8 patients had proven/probable IPA, 16 had possible IPA and 82 did not have IPA. In patients with proven/probable IPA, specificity of LFD was 94% and GM was 89%; sensitivity of LFD was 38% and GM was 75%. Negative predictive value (NPV) for LFD was 94% and for GM was 98%; positive predictive value (PPV) was 38% for both tests. The use of anti-mould prophylaxis did not affect specificity but resulted in decreased NPV of both LFD and GM. Union and intersection analysis showed no improvement in the performance by using both tests. Among patients at risk for IPA, the diagnostic performance of LFD and GM in BAL fluid appears comparable; specificity is high, but sensitivity of both LFD and GM is poor.

Levels of interleukin (IL)-6 and IL-8 are elevated in serum and bronchoalveolar lavage fluid of haematological patients with invasive pulmonary aspergillosis

Aspergillus spp. have been shown to induce T-helper cell (Th) 1 and Th17 subsets resulting in elevated levels of several cytokines. The objective of this study was to analyse a bundle of cytokines in serum and bronchoalveolar lavage fluid (BALF) in patients with and without invasive pulmonary aspergillosis (IPA). This nested case-control analysis included 10 patients with probable/proven IPA and 20 matched controls without evidence of IPA, out of a pool of prospectively enrolled (2014-2017) adult cases with underlying haematological malignancies and suspected pulmonary infection. Serum samples were collected within 24 hours of BALF sampling. All samples were stored at -70°C for retrospective determination of cytokines. IL-6 and IL-8 were significantly associated with IPA in both serum (P = .011 and P = .028) and BALF (P = .006 and P = .012, respectively), and a trend was observed for serum IL-10 (P = .059). In multivariate conditional logistic regression analysis, IL-10 remained a significant predictor of IPA in serum and IL-8 among BALF cytokines. In conclusion, levels of IL-6 and IL-8 were significantly associated with probable/proven IPA, and a similar trend was observed for serum IL-10. Future cohort studies should determine the diagnostic potential of these cytokines for IPA, and evaluate combinations with other IPA biomarkers/diagnostic tests.

Effect of involved Aspergillus species on galactomannan in bronchoalveolar lavage of patients with invasive aspergillosis

PURPOSE

The detection of galactomannan (GM) in bronchoalveolar lavage (BAL) fluid is an important surrogate marker for the early diagnosis and therapeutic monitoring of invasive aspergillosis (IA), regardless of the involved species of Aspergillus. Here, we utilized the Platelia Aspergillus GM enzyme immunoassay (Bio-Rad) to evaluate the GM index in BAL fluid samples from patients with proven, probable or putative IA due to Aspergillusflavus versus Aspergillusfumigatus.

METHODOLOGY

In a prospective study between 2009 and 2015, 116 BAL samples were collected from suspected IA patients referred to two university hospitals in Tehran, Iran.

KEY FINDINGS

According to European Organization for Research and Treatment of Cancer and Mycoses Study Group and Blot criteria, 35 patients were classified as IA patients, of which 33 cases tested positive for GM above 0.5 and, among these patients, 22 had a GM index ≥1. Twenty-eight were culture positive for A. flavus and seven for A. fumigatus. The GM index for A. flavus cases was between 0.5-6.5 and those of A. fumigatus ranged from 1 to 6.5. The sensitivity and specificity of a GM index ≥0.5 in cases with A. flavus were 86 and 88 % and for A. fumigatus patients were 100 and 73 %, respectively.

CONCLUSION

Overall, the mean GM index in patients with A. fumigatus (3.1) was significantly higher than those of A. flavus (1.6; P-value=0.031) and the sensitivity of GM lower for A. flavus when compared to A. fumigatus. This finding has implications for diagnosis in hospitals and countries with a high proportion of A. flavus infections.

Far-Forward Diagnostics in Toxic Industrial Chemical and Material Exposure Scenarios and Biomarker Identification

: This study describes key technical solutions for detecting environmental toxicants and diagnosing adverse health effects in military operational settings as outlined at a symposium cosponsored by the Department of Defense and the Johns Hopkins University-Applied Physics Laboratory (October 27 to 28, 2015). Such technologies are urgently needed in order to provide critical decision-aid tools and prognostic assessment of potential clinical sequelae. This review summarizes the state-of-the-science on (1) prioritization of adverse health effects, (2) existing technologies and diagnostic tools available for use in theater, (3) challenges to advancing diagnostic tools far-forward, and (4) the potential utility of anchoring diagnostic tools to adverse outcome pathways. Emerging technologies are increasingly available for physiological, environmental, and individual exposure monitoring. Challenges to overcome in austere environments include cold chain requirements and determination of adequate sampling intervals.

Early diagnosis of invasive mould infections and disease

Invasive mould infections (IMIs), such as invasive aspergillosis or mucormycosis, are a major cause of death in patients with haematological cancer and in patients receiving long-term immunosuppressive therapy. Early diagnosis and prompt initiation of antifungal therapy are crucial steps in the management of patients with IMI. The diagnosis of IMI remains a major challenge, with an increased spectrum of fungal pathogens and a diversity of clinical and radiological presentations within the expanding spectrum of immunocompromised hosts. Diagnosis is difficult to establish and is expressed on a scale of probability (proven, probable and possible). Imaging (CT scan), microbiological tools (direct examination, culture, PCR, fungal biomarkers) and histopathology are the pillars of the diagnostic work-up of IMI. None of the currently available diagnostic tests provides sufficient sensitivity and specificity alone, so the optimal approach relies on a combination of multiple diagnostic strategies, including imaging, fungal biomarkers (galactomannan and 1,3-β-d-glucan) and molecular tools. In recent years, the development of PCR for filamentous fungi (primarily Aspergillus or Mucorales) and the progress made in the standardization of fungal PCR technology, may lead to future advances in the field. The appropriate diagnostic approach for IMI should be individualized to each centre, taking into account the local epidemiology of IMI and the availability of diagnostic tests.

Clinical characteristics, radiologic findings, risk factors and outcomes of serum galactomannan-negative invasive pulmonary aspergillosis

BACKGROUND

The sensitivity of galactomannan (GM) assay is suboptimal for detecting invasive pulmonary aspergillosis (IPA) in serum samples. However, the clinical characteristics, radiologic findings, and outcomes in patients with GM-negative IPA have not been fully elucidated.

METHODS

Over a 7-year period, adult patients with proven or probable IPA by the EORTC/MSG definition were retrospectively enrolled. Patients with negative GM results and positive Aspergillus spp. cultures from sputum or bronchoalveolar lavage were classified into GM-negative IPA group. GM-positive and culture-negative IPA cases were selected at a 1:2 ratio.

RESULTS

Thirty-four patients with GM-negative IPA were compared to 68 randomly selected patients from 158 patients with GM-positive and culture-negative IPA. Patients with diabetes mellitus, chronic kidney disease, and steroid use were more common but those with hematologic malignancy, prior receipt of mold-active antifungal drugs, and neutropenia were less common in GM-negative IPA than in GM-positive IPA. Regarding radiologic findings, angioinvasive aspergillosis was less common in GM-negative IPA than in GM-positive IPA. The median number of days from diagnosis to appropriate antifungal therapy was higher in GM-negative IPA than in GM-positive IPA. Multivariate analysis indicated that neutropenia (adjusted odds ratio [aOR], 0.10) and prior receipt of mold-active antifungal drugs (aOR, 0.12) were inversely associated with GM-negative IPA. The 30-day and 90-day mortality were similar between the two groups.

CONCLUSION

Neutropenia and prior receipt of mold-active antifungal drugs before GM assay were independently associated with GM positivity among patients with proven/probable IPA. Angioinvasive aspergillosis was less common in GM-negative IPA than in GM-positive IPA.

Fungal Pneumonia in Patients with Hematologic Malignancy and Hematopoietic Stem Cell Transplantation

Fungal pneumonias cause unacceptable morbidity among patients with hematologic malignancies (HM) and recipients of hematopoietic stem cell transplantation (HSCT). The high incidence of fungal pneumonias in HM/HSCT populations arises from their frequently severe, complex, and persistent immune dysfunction caused by the underlying disease and its treatment. The cytopenias, treatment toxicities, and other immune derangements that make patients susceptible to fungal pneumonia frequently complicate its diagnosis and increase the intensity and duration of antifungal therapy. This article addresses the host factors that contribute to susceptibility, summarizes diagnostic recommendations, and reviews current guidelines for management of fungal pneumonia in patients with HM/HSCT.

Translational Development and Application of (1→3)-β-d-Glucan for Diagnosis and Therapeutic Monitoring of Invasive Mycoses

Early diagnosis and prompt initiation of appropriate antimicrobial therapy are crucial steps in the management of patients with invasive fungal infections. However, the diagnosis of invasive mycoses remains a major challenge in clinical practice, because presenting symptoms may be subtle and non-invasive diagnostic assays often lack sensitivity and specificity. Diagnosis is often expressed on a scale of probability (proven, probable and possible) based on a constellation of imaging findings, microbiological tools and histopathology, as there is no stand-alone assay for diagnosis. Recent data suggest that the carbohydrate biomarker (1→3)-β-d-glucan may be useful in both the diagnosis and therapeutic monitoring of invasive fungal infections due to some yeasts, molds, and dimorphic fungi. In this paper, we review recent advances in the use of (1→3)-β-d-glucan to monitor clinical response to antifungal therapy and explore how this assay may be used in the future.

Improving outcome of fungal diseases - Guiding experts and patients towards excellence

Invasive fungal infections are on the rise and during recent years understanding the epidemiology of fungal infections improved. Over 1 billion people are affected and 25 million patients are at imminent risk of severe organ damage or death due to fungal infection. The European Confederation of Medical Mycology (ECMM), founded in 1993, is the roof organisation of 23 National Medical Mycology Societies in Europe. ECMM fights fungal infections at various levels, by creating and distributing scientific knowledge and promoting scientific exchange. In response to the increasing prevalence and management complexity of invasive fungal infections, ECMM recently launched three additional initiatives (https://www.ecmm.info/). (i) ECMM together with other European infectious diseases societies created a comprehensive set of European guidelines for the diagnostic and therapeutic management of invasive fungal infections. (ii) ECMM founded the ECMM Academy awarding fellow status (FECMM) to outstanding researchers who advanced medical mycology. The academy aims at strengthening networking activities between these researchers. (iii) Centres throughout the world can apply for ECMM Excellence Center Status. Following such application on site auditing of up to three levels of mycological work (clinical, microbiological, epidemiological/clinical trials) evaluates the excellence of a centre along predefined criteria. All three initiatives share a common ambition; they aim at improving outcome of fungal diseases through guiding experts and patients towards excellence. Acknowledging fungal infections as a global problem, all three initiatives explicitly reach out beyond European borders.

Evaluating the use of PCR for diagnosing invasive aspergillosis

INTRODUCTION

Aspergillus species, primarily Aspergillus fumigatus, are still the most emerging fungal pathogens. Within recent years, novel molecular methods have been developed to improve the diagnosis of life-threatening invasive aspergillosis in high risk patients. Especially patients with malignant hematological diseases undergoing intensive chemotherapy are at risk and mortality rates are exceptionally high, in part due to difficulties and delays in establishing a microbiologic diagnosis. Early diagnosis and treatment are crucial for an adequate therapeutical management, but, however, are hardly achieved in the clinical setting because most of the current conventional diagnostic tools either lack specificity or acceptable sensitivity at the critical early phase of the infection. Areas covered: To review the clinical value, advantages and problems as well as drawbacks of molecular approaches, especially polymerase chain reaction (PCR)-based assays to detect genomic DNA of Aspergillus species in clinical samples of immunocompromised, especially hematological patients at high risk for IA, a comprehensive review of the literature was performed and expert opinion was expressed. Expert commentary: The results of numerous attempts to diagnose invasive aspergillosis by PCR-based detection of fungal genome in clinical samples highlight the potential of the PCR technique to improve early diagnosis of invasive aspergillosis in patients with hematological malignancies during intensive antineoplastic treatment, combined with imaging surveillance and serologic diagnostic tools. Further comparative validation of reliable assays in prospective multicenter studies is mandatory and urgently needed in order to establish a harmonization and standardization, so that 'gold standard assays' may be incorporated into diagnostic and therapeutic algorithms that improve the prognosis of patients with life-threatening infections caused by Aspergillus species.

Progress in the Diagnosis of Invasive Fungal Disease in Children

PURPOSE OF REVIEW

This review summarizes the fungal diagnostic measures currently available for use in paediatric patients at high risk for developing invasive fungal disease (IFD) and those suspected of having an IFD. The clinical utility of each test is described based on reported performances of individual tests in specific paediatric populations.

RECENT FINDINGS

Available studies in the paediatric population are scarce and are characterized by a huge heterogeneity in underlying diseases (e.g. different risk for IFD), different study objectives and management strategies (screening versus diagnostic) used.

SUMMARY

A final valuation of paediatric studies on fungal diagnostic tools is limited. While the galactomannan and fungal PCR assays are useful to exclude the presence of IFD, it is unclear if mannan, mannan antibodies and β-D-glucan are of benefit due to a lack of studies or validation of the cut-off, respectively. Well-designed multicentre paediatric studies are urgently needed to improve the outcome of IFD.

Lateral Flow Assays for the Diagnosis of Invasive Aspergillosis: Current Status

PURPOSE OF REVIEW

Diagnosis during early stages of invasive aspergillosis (IA) and targeted antifungal treatment has the potential to improve survival significantly. Despite advances in the diagnostic arsenal, invasive mold infections remain difficult to diagnose-especially at early stages before typical radiological signs develop. Varying availability and time-to-results are important limitations of current approved biomarkers and molecular assays for diagnosis of IA. Here, we will give an update on the Aspergillus-specific lateral-flow device (LFD) test. We further review promising findings on feasibility of point-of-care (POC) detection of urinary excreted fungal galactomannan-like antigens.

RECENT FINDINGS

POC LFD assays for detection of Aspergillus antigens are currently in development. The Aspergillus-specific LFD test, which is based on the JF5 antibody (Ab), detects an extracellular glycoprotein antigen secreted during active growth of Aspergillus spp. The test has shown promising results in various studies. In addition, a monoclonal Ab476-based LFD for POC detection of urinary excreted fungal galactomannan-like antigens has been developed but needs further validation.

SUMMARY

Important advances have been made in the development of LFD assays for IA. Most promising is the Aspergillus-specific LFD test; commercial availability is still pending, however. The search for reliable POC tests for other molds, including mucorales, continues.

Measuring (1,3)-β-D-glucan in tracheal aspirate, bronchoalveolar lavage fluid, and serum for detection of suspected Candida pneumonia in immunocompromised and critically ill patients: a prospective observational study

Background

While Candida pneumonia is life-threatening, biomarker measurements to early detect suspected Candida pneumonia are lacking. This study compared the diagnostic values of measuring levels of (1, 3)-β-D-glucan in endotracheal aspirate, bronchoalveolar lavage fluid, and serum to detect suspected Candida pneumonia in immunocompromised and critically ill patients.

Methods

This prospective, observational study enrolled immunocompromised, critically ill, and ventilated patients with suspected fungal pneumonia in mixed intensive care units from November 2010 to October 2011. Patients with D-glucan confounding factors or other fungal infection were excluded. Endotracheal aspirate, bronchoalveolar lavage fluid and serum were collected from each patient to perform a fungal smear, culture, and D-glucan assay.

Results

After screening 166 patients, 31 patients completed the study and were categorized into non-Candida pneumonia/non-candidemia (n = 18), suspected Candida pneumonia (n = 9), and non-Candida pneumonia/candidemia groups (n = 4). D-glucan levels in endotracheal aspirate or bronchoalveolar lavage were highest in suspected Candida pneumonia, while the serum D-glucan level was highest in non-Candida pneumonia/candidemia. In all patients, the D-glucan value in endotracheal aspirate was positively correlated with that in bronchoalveolar lavage fluid. For the detection of suspected Candida pneumonia, the predictive performance (sensitivity/specificity/D-glucan cutoff [pg/ml]) of D-glucan in endotracheal aspirate and bronchoalveolar lavage fluid was 67%/82%/120 and 89%/86%/130, respectively, accounting for areas under the receiver operating characteristic curve of 0.833 and 0.939 (both P < 0.05), respectively. Measuring serum D-glucan was of no diagnostic value (area under curve =0.510, P = 0.931) for the detection of suspected Candida pneumonia in the absence of concurrent candidemia.

Conclusions

D-glucan levels in both endotracheal aspirate and bronchoalveolar lavage, but not in serum, provide good diagnostic values to detect suspected Candida pneumonia and to serve as potential biomarkers for early detection in this patient population.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2364-2) contains supplementary material, which is available to authorized users.

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

We evaluated the usefulness of an Aspergillus galactomannan (GM) test, a β-d-glucan (βDG) 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 βDG testing of BALF, respectively. The sensitivity and specificity of the GM test, βDG 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 βDG tests had the highest diagnostic odds ratio. The combination of the GM and βDG tests on BALF was more useful than any single test for diagnosing CPA.

Utility of bronchoalveolar lavage in diagnosing respiratory tract infections in patients with hematological malignancies: are invasive diagnostics still needed?

BACKGROUND

Patients treated for hematological malignancies have an increased risk of serious infections. Diagnosis and prompt initiation of therapy are essential. Bronchoalveolar lavage (BAL) is a well-established investigation for identifying the cause of pulmonary infiltrates in immunocompromised patients. The aim of the study was to determine the diagnostic yield of BAL in patients treated for hematological malignancies and how often it contributed to a modification of the anti-infectious therapy.

METHODS

We reviewed records from 151 consecutive BAL procedures in 133 adult patients with hematological malignancies, treated at a tertiary hematology unit from 2004 to 2013. Extensive microbiological work-ups on BAL samples had been performed according to a standardized protocol.

RESULTS

A microbiological finding causing the infectious episode could be identified in 59 (39%) cases. In 44 (29%) of the cases, results from BAL had an impact on clinical management either by contributing to a specific diagnosis (25%) or by leading to cessation of ongoing microbiological therapy. The most common diagnoses were invasive pulmonary aspergillosis (IPA) and Pneumocystis jirovecii pneumonia (PJP). Diagnoses of IPA and PJP were based on results from BAL in 65% and 93% of cases, respectively. Several microbiological tests on BAL samples rendered no positive results. Complications were few and mainly mild.

CONCLUSION

BAL is still important for either verifying or excluding some of the most important respiratory tract pathogens in patients with hematological malignancies, particularly IPA and PJP. Standardized procedures for BAL sampling should be continually revised to exclude unnecessary microbiological tests.

Current Algorithms in Fungal Diagnosis in the Immunocompromised Host

Invasive fungal diseases (IFDs) are a major cause of morbidity and mortality in immunocompromised patients such as patients with hematological malignancies or allogeneic hematopoietic stem cell transplant recipients. Whereas the definite diagnosis of IFD requires invasive diagnostic procedures, imaging and noninvasive diagnostic assays may help in decision making with regard to the institution and the choice of antifungal agents, the duration of therapy, surgical intervention, and monitoring of fungal manifestations.Unfortunately, signs and symptoms of IFD are often nonspecific in the immunocompromised patient. Therefore, in immunocompromised patients with suspected IFD, all samples collected need to be cultured for fungi, and, in the case of specimens obtained by invasive diagnostic procedures, also microscopically examined. For high sensitivity of the cultural and microscopic approaches, specific media and stains, respectively, are crucial. Non-culture based method such as the detection of galactomannan or ß-d-glucan and molecular tools such as polymerase chain reaction may help in the early diagnosis of IFD. Imaging studies may be indicative for IFD, but invasive diagnostics such as bronchoalveolar lavage and/or biopsy should be pursued in order to identify the causative pathogen. This chapter summarizes the current knowledge on diagnosing IFD and proposes practical help in the use of diagnostic tools.

Molecular diagnosis of invasive mycoses of the central nervous system

INTRODUCTION

In September 2012, the Centers for Disease Control and Prevention (CDC) began investigating an outbreak of fungal meningitis among patients who had received contaminated preservative-free methyl prednisolone acetate injections from the New England Compounding Center in Framingham, Massachusetts. Thousands of patients were potentially exposed to tainted corticosteroids, but establishing the diagnosis of fungal meningitis during the nationwide outbreak was difficult because little was known about the natural history of the disease. Areas covered: The challenges associated with this outbreak highlighted the need for rapid and reliable methodologies to assist in the diagnosis of invasive mycoses of the central nervous system (IMCNS), which may be devastating and difficult to treat. In this paper, we review the causative agents of these potentially-lethal infections, which include cryptococcal meningitis, cerebral aspergillosis, and hematogenous Candida meningoencephalitis. Expert commentary: While microscopy, culture, and histopathologic identification of fungal pathogens remain the gold standard for diagnosis, new platforms and species-specific assays have recently emerged, including lateral flow immunoassays (LFA), matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), and multiplex PCR in conjunction with magnetic resonance (MR) to potentially aid in the diagnosis of IMCNS.

Non-Invasive Methods to Diagnose Fungal Infections in Pediatric Patients with Hematologic Disorders

Background

Invasive fungal infection (IFIs) is a major infectious complication in immunocompromised patients. Early diagnosis and initiation of antifungal therapy is important to achieve the best outcome.

Objectives

The current study aimed to investigate the incidence of IFIs and evaluate the diagnostic performance of non-invasive laboratory tests: serologic (β-D-glucan, galactomannan) and molecular (nested polymerase chain reaction) tests to diagnose fungal infections in hematologic pediatric patients.

Patients and Methods

In a cross-sectional study from October 2014 to January 2015, 321 blood samples of 62 pediatric patients with hematologic disorders and at high risk for fungal infections were analyzed. Non-invasive tests including the Platelia Aspergillus enzyme immunoassay (EIA) to detect galactomannan antigen, Glucatell for β–D–glucan and nested PCR to detect Candida and Aspergillus species-specific DNA were used in a weekly screening strategy.

Results

Twenty six patients (42%) were considered as proven and probable IFIs, including 3 (5%) proven and 23 (37%) probable cases. Eighteen patients (29%) were considered as possible cases. The sensitivity, specificity, positive and negative predictive values for galactomannan test in 26 patients with proven and probable fungal infections were 94.4%, 100%, 100% and 94.7%; for β-D-glucan test 92.3%, 77.7%, 85%, 87.5% and for nested-PCR were 84.6%, 88.8%, 91.7% and 80%, respectively.

Conclusions

The rate of IFIs in pediatric patients with hematologic disorders is high, and sample collection from the sterile sites cannot be performed in immunocompromised patients. Detection of circulating fungal cell wall components and DNA in the blood using non-invasive methods can offer diagnostic help in patients with suspected IFIs. Their results should be interpreted in combination with clinical, radiological and microbiological findings.

PCR methodology and applications for the detection of human fungal pathogens

INTRODUCTION

Polymerase chain reaction (PCR) has emerged as a promising technology for the rapid and reliable detection and identification of medical mycoses. Recent technological advancements - including microarray, multiplex PCR with magnetic resonance, and beacon probes - have mitigated the technical difficulties of performing nucleic amplification in fungi, thereby improving the sensitivity and specificity of PCR-based assays. In this paper, we examine current applications of PCR in the diagnosis of human fungal infections and look ahead to emerging techniques that may play a larger role in molecular diagnostics in the future.

AREAS COVERED

This review includes a brief overview of the advantages and disadvantages of PCR using various clinical specimens, manual versus automated DNA extraction procedures, panfungal versus specific targets, and spectrum of pathogens detected. This is followed by a brief synopsis of species-specific PCR approaches and a more in-depth look at the obstacles to widespread implementation. Expert commentary: The review concludes with a short perspective for the next five years, including the hurdles to standardization and validation, as well as the role of PCR coupled with electrospray-ionization mass spectrometry (PCR/ESI-MS) or nuclear magnetic resonance for the diagnosis of medical mycoses.

Antifungal prophylaxis in liver transplant recipients: one size does not fit all

BACKGROUND

Targeted antifungal prophylaxis against Candida species or against Candida species and Aspergillus species, according to individual patient risk factors (RFs), is recommended by experts. However, recent studies have reported fluconazole is as effective as broader spectrum antifungals for preventing invasive fungal infection (IFI) after liver transplantation (LT).

METHODS

We performed a retrospective cohort study of all adult patients who underwent LT at our 1420-bed tertiary teaching hospital, from June 2010 to December 2014, to assess the rate and etiology of IFI within 100 days after LT, to investigate the compliance with targeted prophylaxis, and to analyze risk factors for developing IFI.

RESULTS

In total, 303 patients underwent LT. Patients were classified as having low (no RFs), intermediate (1 RF for invasive candidiasis [IC]), and high risk (1 RF for invasive aspergillosis [IA] or ≥2 RFs for IC) for IFI in 20%, 30%, and 50% of cases, respectively. A total of 139 patients received antifungal prophylaxis: 98 with a mold-active drug and 41 with fluconazole. Overall adherence to targeted prophylaxis was 53%. Nineteen patients (6.3%) developed IFI: 7 IC and 12 IA. Multivariate Cox regression analysis, adjusted for median model for end-stage liver disease score at LT, stratification risk group, and adherence to targeted prophylaxis, showed that graft dysfunction, renal replacement therapy, and prophylaxis with fluconazole were independent risk factors for IFI. Seven of the 9 patients who received fluconazole prophylaxis and developed IFI were classified as having high risk for IFI, and 6 developed IA.

CONCLUSION

Recommended stratification is accurate for predicting patients at very high risk for IFI, who should receive prophylaxis with a mold-active drug.

Comparison of 1,3-β-d-glucan with galactomannan in serum and bronchoalveolar fluid for the detection of Aspergillus species in immunosuppressed mechanical ventilated critically ill patients

PURPOSE

Invasive pulmonary aspergillosis (IPA) is an important cause of morbidity/mortality in immunocompromised critically ill patients. New diagnostic strategies for early detection of IPA include the noninvasive biomarkers 1,3-β-d-glucan (BDG), serum, and bronchoalveolar (BAL) fluid galactomannan (GM). The aim of this study was to compare these markers for early detection of IPA in immunosuppressed critically ill patients.

METHODS

Between December 2014 and December 2015, 49 immunosuppressed patients with respiratory failure were treated at our intensive care unit (ICU). We compared the BDG Fungitell assay with GM Platelia assay in serum and BAL for early detection of IPA. All tests were performed initially after admission at the ICU.

RESULTS

In our study with 49 patients, 13 (26%) had probable IPA. These patients had a higher Acute Physiology And Chronic Health Evaluation II score (28 vs 23, P<.001), Sequential Organ Failure Assessment score (16 vs 14, P<.001), more neutropenia (77% vs 30%, P<.001), worse Horowitz Index (99 vs 73 P<.020), a longer ICU stay (26 vs 17 days, P<.044), and a higher mortality rate (77% vs 58%, P<.001) as compared with patients without probable IPA. The used biomarker BDG presented in patients with probable IPA showed significantly higher levels as compared with patients without probable IPA (375 [103-1000 pg/mL; P<.001] vs 64 [30-105 pg/mL; P < .001]). Comparison of BDG with GM showed that positive serum GM could be detected in only 4 (30%), whereas positive BAL GM could be detected in 12 (92%; mean optical density index, 3.7) of 13 probable IPA cases. These results can be expressed as an overall sensitivity of 88% and a specificity of 82% for probable IPA using the BDG Fungitell assay, a sensitivity of 35% and a specificity of 70% using the serum GM Platelia assay, and a sensitivity of 70% and a specificity of 94% using the BAL GM Platelia assay. The negative predictive values of the used tests were 94% for the BDG Fungitell assay, 94% for the serum GM Platelia assay, and 90% for the BAL GM Platelia assay.

CONCLUSION

1,3-β-d-Glucan may be a useful marker for patients under surveillance at risk for IPA. In critically ill patients with immunosuppression, early diagnosis of IPA may be improved by BDG as compared with serum GM. However, diagnostic performance and accuracy increase when BDG is run in parallel with GM from BAL; moreover, the association of the 2 parameters has also the advantage of detecting early and reliable IPA.

Recent developments in the management of invasive fungal infections in patients with oncohematological diseases

Patients with hematological cancer have a high risk of invasive fungal diseases (IFDs). These infections are mostly life threatening and an early diagnosis and initiation of appropriate antifungal therapy are essential for the clinical outcome. Most commonly, Aspergillus and Candida species are involved. However, other non-Aspergillus molds are increasingly be identified in cases of documented IFDs. Important risk factors are long lasting granulocytopenia with neutrophil counts below 500/μl for more than 10 days or graft-versus-host disease resulting from allogeneic stem-cell transplantation. For definite diagnosis of IFD, various diagnostic tools have to be applied, including conventional mycological culture and nonconventional microbiological tests such as antibody/antigen and molecular tests, as well as histopathology and radiology. In the last few years, various laboratory methods, like the Aspergillus GM immunoassay (Aspergillus GM EIA), 1,3-ß-D-glucan (BG) assay or polymerase chain reaction (PCR) techniques have been developed for better diagnosis. Since no single indirect test, including radiological methods, provides the definite diagnosis of an invasive fungal infection, the combination of different diagnostic procedures, which include microbiological cultures, histological, serological and molecular methods like PCR together with the pattern of clinical presentation, may currently be the best strategy for the prompt diagnosis, initiation and monitoring of IFDs. Early start of antifungal therapy is mandatory, but clinical diagnostics often do not provide clear evidence of IFD. Integrated care pathways have been proposed for management and therapy of IFDs with either the diagnostic driven strategy using the preemptive antifungal therapy as opposed to the clinical or empirical driven strategy using the 'traditional' empirical antifungal therapy. Antifungal agents preferentially used for systemic therapy of invasive fungal infections are amphotericin B preparations, fluconazole, voriconazole, posaconazole, caspofungin, anidulafungin, micafungin, and most recently isavuconazole. Clinical decision making must consider licensing status, local experience and availability, pharmacological and economic aspects.

Rapid detection of fungal pathogens in bronchoalveolar lavage samples using panfungal PCR combined with high resolution melting analysis

Despite advances in the treatment of invasive fungal diseases (IFD), mortality rates remain high. Moreover, due to the expanding spectrum of causative agents, fast and accurate pathogen identification is necessary. We designed a panfungal polymerase chain reaction (PCR), which targets the highly variable ITS2 region of rDNA genes and uses high resolution melting analysis (HRM) for subsequent species identification. The sensitivity and specificity of this method was tested on a broad spectrum of the most clinically important fungal pathogens including Aspergillus spp., Candida spp. and mucormycetes. Despite the fact that fluid from bronchoalveolar lavage (BAL) is one of the most frequently tested materials there is a lack of literature sources aimed at panfungal PCR as an IFD diagnostic tool from BAL samples. The applicability of this method in routine practice was evaluated on 104 BAL samples from immunocompromised patients. Due to high ITS region variability, we obtained divergent melting peaks for different fungal species. Thirteen out of 18 patients with proven or probable IFD were positive. Therefore, the sensitivity, specificity, positive predictive value and negative predictive value of our method were 67%, 100%, 100%, and 94%, respectively. In our assay, fungal pathogens identification is based on HRM, therefore omitting the expensive and time consuming sequencing step. With the high specificity, positive and negative predictive values, short time needed to obtain a result, and low price, the presented assay is intended to be used as a quick screening method for patients at risk of IFD.

Filamentous Fungi

Filamentous mycoses are often associated with significant morbidity and mortality. Prompt diagnosis and aggressive treatment are essential for good clinical outcomes in immunocompromised patients. The host immune response plays an essential role in determining the course of exposure to potential fungal pathogens. Depending on the effectiveness of immune response and the burden of organism exposure, fungi can either be cleared or infection can occur and progress to a potentially fatal invasive disease. Nonspecific cellular immunity (i.e., neutrophils, natural killer [NK] cells, and macrophages) combined with T-cell responses are the main immunologic mechanisms of protection. The most common potential mold pathogens include certain hyaline hyphomycetes, endemic fungi, the Mucorales , and some dematiaceous fungi. Laboratory diagnostics aimed at detecting and differentiating these organisms are crucial to helping clinicians make informed decisions about treatment. The purpose of this chapter is to provide an overview of the medically important fungal pathogens, as well as to discuss the patient characteristics, antifungal-therapy considerations, and laboratory tests used in current clinical practice for the immunocompromised host.

Point of Care Testing for the Diagnosis of Fungal Infections: Are We There Yet?

Diagnostic tools for invasive fungal infections have continuously improved within the last decades. Nowadays, cultural methods, antigen testing, and molecular tests, such as polymerase chain reaction, are widely used. These methods, however, are accompanied with different limitations as various availability, various turnaround time or high costs. A new generation of point-of-care test has shown promising results in various studies and may overcome some of these limitations. We therefore reviewed the literature for the most promising new point-of-care tests for invasive aspergillosis (Aspergillus-specific lateral-flow device test, Aspergillus proximity ligation antigen assay), cryptococcosis (cryptococcal lateral-flow assay), and for histoplasmosis (loop-mediated isothermal amplification assay).

Detection of a Serum Siderophore by LC-MS/MS as a Potential Biomarker of Invasive Aspergillosis

Invasive aspergillosis (IA) is a life-threatening systemic mycosis caused primarily by Aspergillus fumigatus. Early diagnosis of IA is based, in part, on an immunoassay for circulating fungal cell wall carbohydrate, galactomannan (GM). However, a wide range of sensitivity and specificity rates have been reported for the GM test across various patient populations. To obtain iron in vivo, A. fumigatus secretes the siderophore, N,N',N"-triacetylfusarinine C (TAFC) and we hypothesize that TAFC may represent a possible biomarker for early detection of IA. We developed an ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for TAFC analysis from serum, and measured TAFC in serum samples collected from patients at risk for IA. The method showed lower and upper limits of quantitation (LOQ) of 5 ng/ml and 750 ng/ml, respectively, and complete TAFC recovery from spiked serum. As proof of concept, we evaluated 76 serum samples from 58 patients with suspected IA that were investigated for the presence of GM. Fourteen serum samples obtained from 11 patients diagnosed with probable or proven IA were also analyzed for the presence of TAFC. Control sera (n = 16) were analyzed to establish a TAFC cut-off value (≥6 ng/ml). Of the 36 GM-positive samples (≥0.5 GM index) from suspected IA patients, TAFC was considered positive in 25 (69%). TAFC was also found in 28 additional GM-negative samples. TAFC was detected in 4 of the 14 samples (28%) from patients with proven/probable aspergillosis. Log-transformed TAFC and GM values from patients with proven/probable IA, healthy individuals and SLE patients showed a significant correlation with a Pearson r value of 0.77. In summary, we have developed a method for the detection of TAFC in serum that revealed this fungal product in the sera of patients at risk for invasive aspergillosis. A prospective study is warranted to determine whether this method provides improved early detection of IA.

Comparison of galactomannan, beta-D-glucan, and Aspergillus DNA in sera of high-risk adult patients with hematological malignancies for the diagnosis of invasive aspergillosis

BACKGROUND/AIM

Invasive aspergillosis (IA) is a fatal infection that is difficult to diagnose in immunocompromised patients. In this study, Aspergillus-specific DNA was searched using real-time PCR (RT-PCR) in serum samples. Galactomannan (GM) and/or beta-D-glucan (BDG) tests were previously performed on these samples for 70 neutropenic patients with hematological malignancy.

MATERIALS AND METHODS

The patients were categorized according to the criteria of the European Organization for Research and Treatment of Cancer/Mycoses Study Group (EORTC/MSG). Among the patient serum samples, the first positive GM or BDG test sample and the median sample of GM or BDG test for negative patients were used to detect DNA levels by RT-PCR method (Light Cycler 480, Roche Molecular Biochemicals, Meylan, France) using a commercial kit (Way2Gene Fungi; Genmar, İzmir, Turkey).

RESULTS

When the proven and probable IA group were considered as real patients, sensitivity of Aspergillus-specific DNA test was 90%, specificity was 73.3%, positive predictive value was 81.8%, and negative predictive value was 84.6%.

CONCLUSION

This study found that searching for specific DNA by RT-PCR method has a sensitivity as high as the GM test. Although specificity was rather low, it was concluded that it can be used jointly with GM and BDG tests after decreasing contamination by severe laboratory applications.

Performance of lateral flow device and galactomannan for the detection of Aspergillus species in bronchoalveolar fluid of patients at risk for invasive pulmonary aspergillosis

Early diagnosis of invasive pulmonary aspergillosis (IPA) remains difficult due to the variable performance of the tests used. We compared the performance characteristics of Aspergillus lateral flow device (LFD) in bronchoalveolar lavage (BAL) vs. BAL-galactomannan (GM), for the diagnosis of IPA. 311 BAL specimens were prospectively collected from patients who underwent bronchoscopy from January to May 2013. Patients at risk for IPA were divided into haematological malignancy (HEM) and non-HEM groups: solid organ transplants (SOT) (lung transplant (LT) and non-LT SOT); chronic steroid use (CSU); solid tumour (STU) and others. We identified 96 patients at risk for IPA; 89 patients (93%) were in the non-HEM groups: SOT 57 (LT, 46, non-LT SOT, 11); CSU 21; STU 6, other 5. Only three patients met criteria for IA (two probable; one possible). Overall sensitivity (SS) was 66% for both and specificity (SP) was 94% vs. 52% for LFD and GM respectively. LFD and GM performance was similar in the HEM group (SS 100% for both and SP 83% vs. 100% respectively). LFD performance was better than GM among non-HEM SOT patients (P = 0.02). Most false-positive GM results occurred in the SOT group (50.8%), especially among LT patients (56.5%). LFD performance was superior with an overall SP of 95.6% in SOT (P < 0.002) and 97% in LT patients (P = 0.0008). LFD is a rapid and simple test that can be performed on BAL to rule out IPA.

Urine Galactomannan-to-Creatinine Ratio for Detection of Invasive Aspergillosis in Patients with Hematological Malignancies

Galactomannan (GM) testing of urine specimens may provide important advantages, compared to serum testing, such as easy noninvasive sample collection. We evaluated a total of 632 serial urine samples from 71 patients with underlying hematological malignancies and found that the urine GM/creatinine ratio, i.e., (urine GM level × 100)/urine creatinine level, which takes urine dilution into account, reliably detected invasive aspergillosis and may be a promising diagnostic tool for patients with hematological malignancies. (This study has been registered at ClinicalTrials.gov under registration no. NCT01576653.).