Jürgen Prattes

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

ABSTRACT Galactomannan detection in bronchoalveolar lavage (BAL) fluid samples (GM test) is currently considered the gold standard test for diagnosing invasive pulmonary aspergillosis (IPA). The limitations, however, are the various turnaround times and availability of testing. We compared the performance of GM testing with that of conventional culture, an Aspergillus lateral-flow-device (LFD) test, a beta-d-glucan (BDG) test, and an Aspergillus PCR assay by using BAL fluid samples from immunocompromised patients. A total of 78 BAL fluid samples from 78 patients at risk for IPA (74 samples from Graz and 4 from Mannheim) collected between December 2012 and May 2013 at two university hospitals in Austria and Germany were included. Three patients had proven IPA, 14 probable IPA, and 17 possible IPA, and 44 patients had no IPA. The diagnostic accuracies of the different methods for probable/proven IPA were evaluated. The diagnostic odds ratios were the highest for the GM, PCR, and LFD tests. The sensitivities for the four methods (except culture) were between 70 and 88%. The combination of the GM (cutoff optical density index [ODI], >1.0) and LFD tests increased the sensitivity to 94%, while the combination of the GM test (>1.0) and PCR resulted in 100% sensitivity (specificity for probable/proven IPA, 95 to 98%). The performance of conventional culture was limited by low sensitivity, while that of the BDG test was limited by low specificity. We evaluated established and novel diagnostic methods for IPA and found that the Aspergillus PCR, LFD, and GM tests were the most useful methods for diagnosing the disease by using BAL fluid samples. In particular, the combination of the GM test and PCR or, if PCR is not available, the LFD test, allows for sensitive and specific diagnosis of IPA.

Bronchoalveolar lavage lateral-flow device test for invasive pulmonary aspergillosis in solid organ transplant patients: a semiprospective multicenter study.

Background Invasive pulmonary aspergillosis (IPA) remains an important cause of morbidity and mortality among patients undergoing solid organ transplantation (SOT). Because of the crude mortality of 80% to 90% in the absence of adequate treatment, timely diagnosis and early intervention with antifungal drugs are key factors in the successful treatment of IPA. Diagnosis, however, remains difficult. Therefore, new diagnostic tests are urgently needed. The Lateral-Flow Device (LFD) test is a rapid (15 min) single-sample point-of-care test that is based on the detection of an Aspergillus extracellular glycoprotein antigen by monoclonal antibody JF5. Methods This semiprospective multicenter study evaluated the LFD test for IPA diagnosis (established by galactomannan and culture results) by using bronchoalveolar lavage (BAL) samples from patients after SOT. Participating centers were the three Austrian Medical Universities of Innsbruck, Vienna, and Graz. Results Forty-seven BAL samples from 47 SOT patients were included (26 patients had undergone lung transplantation, 13 liver, 6 kidney, and 2 heart transplantation; 11 probable or proven IPA, 11 possible IPA, 25 no IPA) at the three Austrian Medical Universities of Innsbruck, Vienna, and Graz. Sensitivity and specificity, positive and negative predictive values, as well as diagnostic odds ratio of BAL LFD tests for probable IPA were 91%, 83%, 63%, 97%, and 50% (95% confidence interval, 5.4%–467%), respectively. Conclusion To conclude, the LFD test of BAL specimens is performed easily and provides accurate and rapidly available results in patients after SOT. Therefore, this new point-of-care test may be a promising diagnostic approach for detecting IPA using BAL specimens from SOT patients.

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.

Procalcitonin fails to predict bacteremia in SIRS patients: a cohort study

Procalcitonin (PCT) has previously been proposed as useful marker to rule out bloodstream‐infection (BSI). The objective of this study was to evaluate the sensitivity of different PCT cut‐offs for prediction of BSI in patients with community (CA)‐ and hospital‐acquired (HA)‐BSI.

Impact of structured personal on-site patient education on low posaconazole plasma concentrations in patients with haematological malignancies

Low posaconazole plasma concentrations (PPCs) are associated with breakthrough invasive mould infections among patients with haematological malignancies. This study evaluated the influence of structured personal on-site patient education on low PPCs. The study was conducted from July 2012 to May 2013 at the Division of Hematology, Medical University Hospital of Graz (Graz, Austria). PPCs were measured in all patients with haematological malignancies receiving the drug prophylactically. Concentrations above the target of 0.5 mg/L were defined as satisfactory and those below this concentration as low. In patients with low PPCs, structured personal on-site education regarding the intake of posaconazole (e.g. intake with fatty/acid food, prevention of nausea and vomiting) was performed. In total, 258 steady-state PPCs were measured in 65 patients [median PPC 0.59 mg/L, interquartile range 0.25-0.92 mg/L; 141/258 (54.7%) satisfactory]. Diarrhoea was the strongest predictor of low PPCs in the multivariate analysis. Initial steady-state PPCs were sufficient in 29 patients and low in 36 patients. Of the 36 patients with low initial steady-state PPCs, 8 were either discharged or antifungal therapy was modified before a follow-up PPC was obtained; in the remaining 28 patients, personal on-site education was performed. In 12/28 patients (43%) the personal on-site education led to sufficient levels, whilst in 16 (57%) PPCs stayed below the target, although increasing from <0.2 mg/L to >0.3 mg/L in 6 of these patients. In conclusion, personal education appears to be a promising tool to increase low PPCs.

Characterisation of Candida within the Mycobiome/Microbiome of the Lower Respiratory Tract of ICU Patients

Whether the presence of Candida spp. in lower respiratory tract (LRT) secretions is a marker of underlying disease, intensive care unit (ICU) treatment and antibiotic therapy or contributes to poor clinical outcome is unclear. We investigated healthy controls, patients with proposed risk factors for Candida growth in LRT (antibiotic therapy, ICU treatment with and without antibiotic therapy), ICU patients with pneumonia and antibiotic therapy and candidemic patients (for comparison of truly invasive and colonizing Candida spp.). Fungal patterns were determined by conventional culture based microbiology combined with molecular approaches (next generation sequencing, multilocus sequence typing) for description of fungal and concommitant bacterial microbiota in LRT, and host and fungal biomarkes were investigated. Admission to and treatment on ICUs shifted LRT fungal microbiota to Candida spp. dominated fungal profiles but antibiotic therapy did not. Compared to controls, Candida was part of fungal microbiota in LRT of ICU patients without pneumonia with and without antibiotic therapy (63% and 50% of total fungal genera) and of ICU patients with pneumonia with antibiotic therapy (73%) (p<0.05). No case of invasive candidiasis originating from Candida in the LRT was detected. There was no common bacterial microbiota profile associated or dissociated with Candida spp. in LRT. Colonizing and invasive Candida strains (from candidemic patients) did not match to certain clades withdrawing the presence of a particular pathogenic and invasive clade. The presence of Candida spp. in the LRT rather reflected rapidly occurring LRT dysbiosis driven by ICU related factors than was associated with invasive candidiasis.

Mycobiome in the Lower Respiratory Tract – A Clinical Perspective

Recently the paradigm that the healthy lung is sterile was challenged and it is now believed that the lungs harbor a diverse microbiota also contributing to the pathogenesis of various diseases. Most of the research studies targeting the respiratory microbiome have focused on bacteria and their impact on lung health and lung diseases. Recently, also the mycobiome has gained attention. Lower respiratory tract (LRT) diseases (e.g., cystic fibrosis) and other diseases or conditions (e.g., HIV infection, lung transplantation, and treatment at intensive care units) have been investigated with regard to possible involvement of mycobiome in development or progression of diseases. It has been shown that diversities of mycobiome in the LRT vary in different populations and conditions. It has been proposed that the mycobiome diversity associated with LRT can vary with different stages of diseases. Overall, Candida was the dominant fungal genus in LRT samples. In this review, we summarize the recent findings regarding the human LRT mycobiome from a clinical perspective focussing on characterization of investigated patient groups and healthy controls as well as sampling techniques. From these data, clinical implications for further studies or routine practice are drawn. To obtain clinically relevant answers efforts should be enhanced to collect well characterized and described patient groups as well as healthy individuals for comparative data analysis and to apply thorough sampling techniques. We need to proceed with elucidation of the role of mycobiota in healthy LRT and LRT diseases to hopefully improve patient care.

Diagnostic performance of 1,3-beta-D-glucan serum screening in patients receiving hematopoietic stem cell transplantation.

The polysaccharide cell wall component, 1,3‐beta‐D‐glucan (BDG), is used as a serum biomarker for invasive fungal infection (IFI). Patients receiving hematopoietic stem cell transplantation (HSCT) are considered a highly vulnerable group for IFI development. We evaluated the diagnostic performance of serum BDG screening in HSCT recipients.

Posaconazole Plasma Concentrations on Days Three to Five Predict Steady-State Levels.

ABSTRACT Low posaconazole plasma concentrations (PPCs) have been associated with breakthrough invasive fungal infections. We assessed the correlation between pre-steady-state PPCs (obtained between days 3 and 5) and PPCs obtained during steady state in 48 patients with underlying hematological malignancies receiving posaconazole oral-solution prophylaxis. Pre-steady-state PPCs correlated significantly with PPCs obtained at steady state (Spearman r = 0.754; P < 0.001). Receiver operating characteristic (ROC) curve analysis of pre-steady-state PPCs revealed an area under the curve (AUC) of 0.884 (95% confidence interval [CI], 0.790 to 0.977) for predicting satisfactory PPCs at steady state.

Elevated Levels of Interleukin 17A and Kynurenine in Candidemic Patients, Compared With Levels in Noncandidemic Patients in the Intensive Care Unit and Those in Healthy Controls

BACKGROUND The interplay between Candida species and pattern recognition receptors, interleukins, kynurenine, and T cells has been studied in murine and ex vivo human studies, but data are lacking from patients with invasive fungal infections. Interleukin 17A (IL-17A) is considered an important component in host defense against Candida infections and is modulated by Candida-induced impairment of tryptophan-kynurenine metabolism. METHODS Dectin-1, Toll-like receptor 2, and Toll-like receptor 4 expression; regulatory T cell (Treg) percentages; and interleukin 6, interleukin 10, IL-17A, interleukin 22, interleukin 23, interferon γ, kynurenine, and tryptophan levels were determined in candidemic patients and compared to levels in noncandidemic patients who are in the intensive care unit (ICU) and receiving antibiotic therapy and those in healthy controls, both with and without Candida colonization. RESULTS Candidemic patients had significantly higher IL-17A and kynurenine levels, compared with noncandidemic patients, including Candida-colonized ICU patients and healthy controls. Within candidemic patients, time-dependent elevation of IL-17A and kynurenine levels was detected. IL-17A areas under the curve for differentiation between patients with early candidemia and those without candidemia (ICU patients, including Candida-colonized patients, and healthy controls) were between 0.94 (95% confidence interval [CI], .89-.99) and 0.99 (95% CI, .99-1). CONCLUSIONS Candidemic patients had significantly higher IL-17A and kynurenine levels, compared with noncandidemic patients. The statistically significant association between IL-17A and kynurenine levels and candidemia suggests their potential as biomarkers for anticipation of invasive candidiasis. CLINICAL TRIALS REGISTRATION NCT00786903.