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Circulating fungal glycans in sera of ICU patients. Clinical relevance and development of physico-chemical methods of detection. J.POISSY 1-2, B.SENDID 2-3, S.DAMIENS 2, R.FAVORY 1, N.FRANCOIS 3, N.GHALEM 3, S.JAWHARA 2, T.JOUAULT 1, D.MATHIEU 1, Y.GUERARDEL 4, D.POULAIN 2-3 1: Pôle de Réanimation, CHRU Lille; 2: UMR Inserm U995 Eq 2, Lille 2; 3: Laboratoire de Parasitologie-Mycologie CHRU Lille; 4: UGSF, UMR 8576 CNRS, Lille 1. U995 Journées André Verbert 11 Sept 2012
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Morrell M et col. AAC. 2005 Adapted from Kumar A et col. ICAAC 2007. K 2174 All patientsPatients with septic shock U995 Journées André Verbert 11 Sept 2012 Candidemia in ICU patients: delay in initiation of antifungal treatment has a high impact on mortality. An early diagnosis is needed Prevalence : 7/1000. Mortality : 42.6%
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Schematic representation of yeast cell wall (Bennett JE. NEJM. 2006) Detection of cell wall molecules circulating in patients’ sera as biomarkers of invasion U995 Immunological detection of Mannans Platelia® ELISA tests. Based on immunocapture with a monoclonal antibody. Introduced in 2003 (Sendid et al). Biochemical detection of glucans Fungitell®test. Based on derivation of Limulus test enzymic cascade rendered specific for glucans. Recently introduced in France. Journées André Verbert 11 Sept 2012
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Aims of the study Evaluation of the clinical relevance of β-D-1,3- glucans detection in ICU and comparison with mannan detection (Diagnostic, theranostic) Development of methods for detection of circulating fungal glycans by Mass Spectrometry U995 Journées André Verbert 11 Sept 2012
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Patients and methods Selection of Patients from Clinical Mycology Laboratory registry – Patients with candidemia from ICU department, CHRU de Lille, from 2005 to 2010 (117 patients) – Sera available at least one week before and one week after blood culture : 43 selected patients, 363 sera. Controls: – Patients hospitalized in the same ward with no evidence of Candida infection (According to EORTC) : 135 patients and 324 sera U995 Journées André Verbert 11 Sept 2012
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Fungitell®: Sensitive but non specific test (cut-off=80 pg/mL) U995 Journées André Verbert 11 Sept 2012
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Receiver Operating Characteristics curve (ROC) U995 Journées André Verbert 11 Sept 2012 Area under the curve: 0.750 Sp=90% for BDG>1150 pg/mL Se/Sp=77/68% for a cut-off at 205 Median rate patients vs controls: 425 vs 119 Higher than cut-off recommanded by manufacturer
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Early presence but slow decrease of glucanemia (little value for treatment follow-up) N=8 N=34 N=32 N=18 N=16 N=13 N=9 N=6 p=0.0019 U995 Journées André Verbert 11 Sept 2012 Median delay of positivity 10 days before blood culture (Cut-off 80 pg/mL)
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Rapid evolution of clinical biology. Mass spectrometry: a new standard equipment in Medical Mycology Laboratories. Adaptation for detection of fungal biomarkers? U995 Journées André Verbert 11 Sept 2012
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Blood culture Incubation Mass spectrometry Spectral profile Culture Susceptibility to ATFs Isolation/identification
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Previous basic studies as a reference for seeking a Candida glucan signal by using MALDI TOF Jawhara S et al; Plos One, 2012 U995 Journées André Verbert 11 Sept 2012
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Development of an original extraction procedure* in order to reduce the signal/noise ratio EDTA+120°C Centrifugation Supernatent with less proteins, Hb, lipids C18 column preconditionned by H2O+acétonitrile After washing : Oligosaccharides, glucose and salts Solid phase extraction Activated coal After washing and elution : oligosaccharides * Patent CHRU/PRES Nord de France/CNRS U995 Journées André Verbert 11 Sept 2012
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Spiking of purified F2 in serum generates a 365 signal even for very low quantities U995 Journées André Verbert 11 Sept 2012 Nb: no correlation between MALDI-TOF and Fungitel test (different molecules detected)
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The 365 signal is present in sera from patients with Candidemia. With reference to peak 361 (Matrix) H 2 Trehalose (Positive internal spiked control) 365 361 365 361 375 U995 Journées André Verbert 11 Sept 2012
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365 MS fungal signature in clinical samples DiseasePositive samples365 vs 361 Healthy subjects0/15 (0%)None Candidemia12/12 (100%)+++ Aspergillosis5/5 (100%)+++ Pneumocystis pneumonia3/5 (60%)+++ U995 Journées André Verbert 11 Sept 2012
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Conclusion/Perspectives There is a « 365 signature » of candidemia in patients sera Explore the range and the nature of «glycans circulating molecular species »(Mannans, glucans, chitin) their diagnostic and pathophysiological significance Development of animal model (rabbit) to speed-up and complement these researches Connection between this R&D project and the ongoing constitution of a cohort to analyse genetic risks factors of candidemia (Promotor code: 2011_63) U995 Journées André Verbert 11 Sept 2012
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