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

Direct comparison of galactomannan performance in concurrent serum and bronchoalveolar lavage samples in immunocompromised patients at risk for invasive pulmonary aspergillosis

Invasive pulmonary aspergillosis (IPA) is a life-threatening infection mainly affecting immunocompromised patients. Early diagnosis is critical, but the diagnostic gold standard (histopathology and culture) is time consuming and cannot offer early confirmation of IPA. Fungal biomarkers like galactomannan (GM) are a promising extension to the diagnostic repertoire. However, it still remains under discussion if biomarker analysis from the site of the infection is superior to testing blood samples. We retrospectively evaluated the diagnostic performance of concurrent serum GM and bronchoalveolar lavage (BAL) GM (obtained within 24 h) of immunocompromised patients at high risk of IPA. Twenty-six proven/probable patients and eight patients with no IPA according to the EORTC/MSG 2008 criteria were included in this study. Sensitivity, specificity, positive predictive value, negative predictive value and diagnostic odds ratio were for BAL GM: 85%, 88%, 96%, 64% and 38.5, and for serum GM: 23%, 88%, 88%, 26% and 2.1 respectively. BAL GM proved to be significantly more sensitive for the detection of IPA compared to same-day serum GM in patients at high risk of IPA (P < 0.0001). Our data show that BAL GM testing is significantly superior to serum GM implying that diagnostic efforts should focus on specimens from the site of infection.

Diagnosis of Invasive Fungal Diseases in Hematological Malignancies: A Critical Review of Evidence and Turkish Expert Opinion (TEO-2)

One of the most problematic issues in hematological malignancies is the diagnosis of invasive fungal diseases. Especially, the difficulty of mycological diagnosis and the necessity of immediate intervention in molds have led to the adoption of “surrogate markers” that do not verify but rather strongly suggest fungal infection. The markers commonly used are galactomannan (GM), beta-glucan, and imaging methods. Although there are numerous studies on these diagnostic approaches, none of these markers serve as a support for the clinician, as is the case in human immunodeficiency virus (HIV) or cytomegalovirus (CMV) infections. This paper has been prepared to explain the diagnostic tests. As molecular tests have not been standardized and are not used routinely in the clinics, they will not be mentioned here.

Aspergillus Polymerase Chain Reaction: Systematic Review of Evidence for Clinical Use in Comparison With Antigen Testing

BACKGROUND

Aspergillus polymerase chain reaction (PCR) was excluded from the European Organisation for the Research and Treatment of Cancer/Mycoses Study Group (EORTC/MSG) definitions of invasive fungal disease because of limited standardization and validation. The definitions are being revised.

METHODS

A systematic literature review was performed to identify analytical and clinical information available on inclusion of galactomannan enzyme immunoassay (GM-EIA) (2002) and β-d-glucan (2008), providing a minimal threshold when considering PCR. Categorical parameters and statistical performance were compared.

RESULTS

When incorporated, GM-EIA and β-d-glucan sensitivities and specificities for diagnosing invasive aspergillosis were 81.6% and 91.6%, and 76.9% and 89.4%, respectively. Aspergillus PCR has similar sensitivity and specificity (76.8%-88.0% and 75.0%-94.5%, respectively) and comparable utility. Methodological recommendations and commercial PCR assays assist standardization. Although all tests have limitations, currently, PCR is the only test with independent quality control.

CONCLUSIONS

We propose that there is sufficient evidence that is at least equivalent to that used to include GM-EIA and β-d-glucan testing, and that PCR is now mature enough for inclusion in the EORTC/MSG definitions.

Prognostic potential of 1,3-beta-d-glucan levels in bronchoalveolar lavage fluid samples

OBJECTIVES

The objective of this study was to investigate the prognostic potential of 1,3-beta-d-glucan (BDG) testing in bronchoalveolar lavage fluid (BALF) samples.

METHODS

A total of 300 BALF samples from 252 patients were investigated for BDG (Fungitell(®) assay). Prognostic potential of BALF BDG was evaluated by using: i.) Kaplan-Meier analysis, and ii.) multivariable Cox hazard regression analyses.

RESULTS

BALF BDG levels were found to be significantly higher in samples with Candida spp. colonization (p < 0.001). A total of 61/252 patients (24.2%) died within 90-days of BALF sampling (18.1% of patients with BALF BDG <200 pg/mL, 32.4% with BALF BDG ≥200 pg/mL). Kaplan-Meier analysis revealed that overall cumulative 90-day mortality was significantly higher in those with BALF BDG levels ≥200 pg/mL when compared to those with levels <200 pg/mL (log-rank p = 0.006, Breslow p = 0.005 and Tarone-Ware p = 0.005). The multivariable Cox regression analysis showed that BALF BDG levels were a strong predictor of 90-day overall mortality, with a hazard ratio of 1.048 (per 100 pg/mL increase of BALF BDG).

CONCLUSION

False positive BALF BDG results in the presence of Candida spp. colonization of the lower respiratory tract may explain the limited diagnostic potential of BALF BDG testing. In contrast, prognostic potential of BALF BDG may be promising.

An Approach to a Pulmonary Infiltrate in Solid Organ Transplant Recipients

The onset of a pulmonary infiltrate in a solid organ transplant (SOT) recipient is both a challenging diagnostic and therapeutic challenge. We outline the potential aetiologies of a pulmonary infiltrate in a SOT recipient, with particular attention paid to fungal pathogens. A diagnostic and empirical therapy approach to a pulmonary infiltrate, especially invasive fungal disease (IFD) in SOT recipients, is provided.

Influence of mould-active antifungal treatment on the performance of the Aspergillus-specific bronchoalveolar lavage fluid lateral-flow device test

The effect of mould-active antifungal (AF) therapy/prophylaxis on the performance of the Aspergillus-specific lateral-flow device (LFD) test for diagnosing invasive pulmonary aspergillosis (IPA) was evaluated. This was a retrospective analysis of patients diagnosed with probable or proven IPA (according to revised EORTC/MSG criteria) at the Medical University of Graz (Austria) and the University Hospital of Mannheim (Germany) between February 2011 and December 2014. In total, 60 patients with 63 bronchoalveolar lavage fluid (BALF) samples were included in the analysis. Patient charts were reviewed regarding AF treatment at the time of bronchoscopy, and the influence of AFs on the performance of the LFD and BALF galactomannan (GM) ELISA results was calculated. Overall, 54 patients (57 BALF samples) had probable IPA and 6 patients (6 samples) had proven IPA. In 21/63 samples (33%) (from 19 patients), systemic mould-active AFs had been initiated before bronchoscopy. Of 63 BALF samples, 16 (25%) yielded a false-negative LFD result. The sensitivity of the LFD for probable/proven IPA was significantly lower in those receiving mould-active AFs compared with those without (52% vs. 86%; P=0.006). Similar results were found for BALF GM, with sensitivities decreasing under systemic AFs (71% vs. 95%, P=0.013 with the 0.5 ODI cut-off; 52% vs. 81%, P=0.036 with the 1.0 cut-off). These results suggest that the sensitivity of the BALF LFD and BALF GM assays may be reduced in the presence of mould-active AF treatment. Negative results in patients on AFs should therefore be interpreted with caution.

Detection of (1→3)-β-D-glucan in same-day urine and serum samples obtained from patients with haematological malignancies

Serum 1,3-beta-d-glucan (BDG) testing is an established diagnostic marker for invasive fungal infections (IFI) among patients with haematological malignancies. In contrast limited data exist regarding the application of urine BDG testing. Same-day midstream urine and serum screening samples were collected in adult patients with underlying haematological malignancies. A total of 80 urine samples from 46 patients were investigated: Twenty-six had positive corresponding serum BDG >120 pg ml(-1), 27 intermediate (60-80 pg ml(-1)), and 27 negative serum BDG (<25 pg ml(-1)). A significant positive correlation between BDG in serum and urine samples was observed (P = 0.025; r = 0.252). Sensitivity, specificity, positive predictive value and negative predictive value (compared with same-day serum results) were: 42%, 76%, 46%, 73% when using an 80 pg ml(-1) urine cut-off, and 35%, 96%, 82%, 75% for a 250 pg ml(-1) cut-off. Urine BDG seemed to be higher in samples obtained from patients with probable IFI (n = 13, median 145, IQR 22-253) compared to those from patients without IFI (n = 56, median 24, IQR 15-88) but the difference was not significant (P = 0.069). Overall correlation of same-day urine BDG and serum BDG was moderate. However, urine BDG testing may warrant further investigation in larger studies, as high-positive urine results correlated with high-positive corresponding serum levels and clinical performance was comparable to serum BDG.

Multicenter evaluation of a lateral-flow device test for diagnosing invasive pulmonary aspergillosis in ICU patients

Introduction

The incidence of invasive pulmonary aspergillosis (IPA) in intensive care unit (ICU) patients is increasing, and early diagnosis of the disease and treatment with antifungal drugs is critical for patient survival. Serum biomarker tests for IPA typically give false-negative results in non-neutropenic patients, and galactomannan (GM) detection, the preferred diagnostic test for IPA using bronchoalveolar lavage (BAL), is often not readily available. Novel approaches to IPA detection in ICU patients are needed. In this multicenter study, we evaluated the performance of an Aspergillus lateral-flow device (LFD) test for BAL IPA detection in critically ill patients.

Methods

A total of 149 BAL samples from 133 ICU patients were included in this semiprospective study. Participating centers were the medical university hospitals of Graz, Vienna and Innsbruck in Austria and the University Hospital of Mannheim, Germany. Fungal infections were classified according to modified European Organization for Research and Treatment of Cancer/Mycoses Study Group criteria.

Results

Two patients (four BALs) had proven IPA, fourteen patients (sixteen BALs) had probable IPA, twenty patients (twenty-one BALs) had possible IPA and ninety-seven patients (one hundred eight BALs) did not fulfill IPA criteria. Sensitivity, specificity, negative predictive value, positive predictive value and diagnostic odds ratios for diagnosing proven and probable IPA using LFD tests of BAL were 80%, 81%, 96%, 44% and 17.6, respectively. Fungal BAL culture exhibited a sensitivity of 50% and a specificity of 85%.

Conclusion

LFD tests of BAL showed promising results for IPA diagnosis in ICU patients. Furthermore, the LFD test can be performed easily and provides rapid results. Therefore, it may be a reliable alternative for IPA diagnosis in ICU patients if GM results are not rapidly available.

Trial registration

ClinicalTrials.gov NCT02058316. Registered 20 January 2014.

Invasive pulmonary aspergillosis - case report and review of literature

Invasive pulmonary aspergillosis (IPA) is a severe fungal infection with a high mortality rate. The incidence of IPA is on the rise due to an increase in the number of patients undergoing transplants and receiving chemotherapy and immunosuppressive therapy. Diagnosis is challenging due to the non-specific nature of symptoms. Voriconazole is the mainstay of therapy. We present a case of an elderly woman presenting with acute bronchitis and asthma exacerbation, who succumbed to overwhelming IPA. It is uncommon for IPA to develop in patients on short-term steroid therapy for asthma exacerbation. The possibility of aspergillosis in immunocompetent patients should be considered in those on systemic steroids and deteriorating pulmonary functions.

Novel tests for diagnosis of invasive aspergillosis in patients with underlying respiratory diseases

RATIONALE

Invasive pulmonary aspergillosis has been increasingly reported in nonneutropenic patients, including those with underlying respiratory diseases.

OBJECTIVES

We compared the diagnostic performances of galactomannan, 1,3-β-D-glucan, and Aspergillus-specific lateral-flow device tests with that of conventional culture by using bronchoalveolar lavage fluid samples from patients with underlying respiratory diseases.

METHODS

We analyzed 268 bronchoalveolar lavage samples from 221 patients with underlying respiratory diseases (and without hematologic malignancy or previous solid organ transplantation) that were collected for routine microbiological workup between February 2012 and May 2014 at the University Hospital of Graz, Austria. Invasive pulmonary aspergillosis was defined according to European Organization of Research and Treatment of Cancer/Mycoses Study Group criteria modified for patients with respiratory diseases.

MEASUREMENTS AND MAIN RESULTS

Thirty-one patients (14%) had probable or proven, 25 possible, and the remaining 165 patients no invasive pulmonary aspergillosis. Probable/proven aspergillosis was associated with a significantly higher (P = 0.034) 30-day mortality rate of 32%. Sensitivities, specificities, and diagnostic odd ratios differed markedly between galactomannan (cut-off 0.5: optical density index, 0.97, 0.81, 124.4; cut-off 1.0: 0.97, 0.93, 422.1; cut-off 3.0: 0.61, 0.99, 109.8), β-D-glucan (cut-off 80 pg/ml: 0.90, 0.42, 6.57; cut-off 200 pg/ml: 0.70, 0.61, 3.7), lateral-flow device tests (0.77, 0.92, 41.8), and mycological culture (0.29, 0.97, 14).

CONCLUSIONS

Probable or proven invasive pulmonary aspergillosis was diagnosed in 14% of our study population and associated with significantly higher 30-day mortality rates. Although the performance of β-D-glucan was limited by low specificity and that of mycological culture by low sensitivity, the Aspergillus lateral-flow device seems to be a promising alternative to galactomannan testing, which remains the diagnostic gold standard for aspergillosis. Clinical trial registered with www.clinicaltrials.gov (NCT 02058316).

Non-cultural methods for the diagnosis of invasive fungal disease

Invasive fungal diseases carry a high mortality risk which can be reduced by early treatment. Diagnosing invasive fungal diseases is challenging, because invasive methods for obtaining histological samples are frequently not feasible in thrombocytopenic immunocompromised patients, while fungal cultures have low sensitivity and a long turn-around time. Non-cultural methods are fundamental for a rapid diagnosis of invasive fungal diseases and they include assays based on the detection of fungal antigens (galactomannan, Aspergillus-lateral flow device, [1,3]-β-D-glucan, mannan), antibodies, such as anti-mannan, and molecular tests. With the exception of some molecular methods for rare fungi, the non-cultural assays are usually applied to the diagnosis of invasive aspergillosis, invasive candidiasis and pneumocystosis. The performance of a single test or a combination of tests will be discussed, with particular focus on choosing the most appropriate marker(s) for every specific patient population. Reasons for potential false-positive or false-negative results will be discussed.

The role of surgical debridement in different clinical manifestations of invasive aspergillosis

Invasive aspergillosis (IA) has a wide spectrum of clinical presentations and is associated with high mortality rates. Early initiation of systemic antimould therapy remains the most important measure to reduce mortality. Surgical debridement is an important additional therapeutic option mainly in cases of extrapulmonary IA. The main intention for surgical intervention in IA is to obtain material for diagnosis and antifungal susceptibility testing. There are, however, also therapeutic implications for surgical interventions in rare manifestation of IA such as endocarditis or mycotic aneurysm. Here, we will review the role of surgical interventions in the treatment of different clinical manifestations of IA.

Serum 1,3-beta-d-glucan for antifungal treatment stratification at the intensive care unit and the influence of surgery

The purpose of this study was to evaluate a preemptive approach with serum 1,3-beta-d-glucan (BDG) as a marker for treatment stratification of systemic antifungal (AF) therapy in patients with clinical suspected invasive fungal infections (IFI) at intensive care units (ICU), and the impact of surgical procedures. A total of 66 ICU patients with clinical suspected IFI were included in this retrospective analysis. Serum BDG testing was performed prior to initiation of AF treatment and in addition to routine diagnostic measures. Based on the BDG results the initial clinical decision whether or not to start systemic AF therapy was re-evaluated. Impact of surgical procedures on clinical utility of serum BDG was evaluated in a sub-group of 25 patients who had undergone surgical procedures prior to BDG evaluation. BDG test results led to discontinuation of AF therapy in 13 patients, and initiation of AF therapy in seven patients. In 46 patients the clinical decision was confirmed by BDG. The majority of suspected, probable and proven IFI cases (10/13, 77%) was predicted by the test. BDG testing turned out positive in 9/25 (36%) of patients that had undergone recent surgery and levels correlated with clinical findings. Serum BDG evaluation seems to be a promising tool to guide AF therapy in ICU patients even after recent surgical procedures.