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Value of rapid antigen detection tests (RADTs) for diagnosis of invasive group A Streptococci (GAS) 3-centre, retrospective study: N=192 miscellaneous.

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Presentation on theme: "Value of rapid antigen detection tests (RADTs) for diagnosis of invasive group A Streptococci (GAS) 3-centre, retrospective study: N=192 miscellaneous."— Presentation transcript:

1 Value of rapid antigen detection tests (RADTs) for diagnosis of invasive group A Streptococci (GAS) 3-centre, retrospective study: N=192 miscellaneous clinical samples (pleural and synovial fluids, subcutaneous, gynaecological/digestive abscesses,...): –GAS+ (by culture and/or 16S rRNA PCR): N=75 –GAS-: N=117 Compare diagnostic value of 3 RADTs with GAS culture and with the ‘gold standard’ GAS-specific real-time PCR (targeting ntpB gene encoding putative V-type Na + ATPase subunit B) Gazzano V. ECCMID 2014 abs. P0623 1 of 2 Data from poster

2 Value of rapid antigen detection tests (RADTs) for diagnosis of invasive group A Streptococci (GAS) The 3 RADTs showed a higher sensitivity than GAS culture, but were less sensitive than GAS-specific PCR. They may be used to speed up diagnosis when invasive GAS infections are suspected Gazzano V. ECCMID 2014 abs. P0623 2 of 2 Data from poster

3 Unique blood culture (UBC) vs multiple blood culture (MBC): diagnostic performance 1-yr, multi-centre, prospective study (France): N=826 pts ≥18 yr admitted to adult ICU with fever ≥38.5°C, hypothermia ≤36.0°C, chills or shock N=300 pts with positive BC (mean age: 67.3 yr): Pathogens: N=245 / Contaminants: N=55 Dargere S. ECCMID 2014 abs. P0484 1 of 2 Data from poster

4 Unique blood culture (UBC) vs multiple blood culture (MBC): diagnostic performance UBC may decrease the # of false positives and false negatives compared with MBC and may lead to significant cost savings 2 of 2 Data from poster Dargere S. ECCMID 2014 abs. P0484 Discrepancies: MBC vs UBC (1 centre): cost savings: 193,275 €/yr (materials, labour time)

5 Unique blood culture (UBC) vs multiple blood culture (MBC): diagnostic performance MBC vs UBC (1 centre): cost savings: 193,275 €/yr (materials, labour time) UBC may decrease the # of false positives and false negatives compared with MBC and may lead to significant cost savings 2 of 2 Data from poster Dargere S. ECCMID 2014 abs. P0484

6 MALDI-TOF for pathogen identification in blood cultures (BCs): improved methods Short-incubation (SI) MALDI-TOF for rapid pathogen identification 1 : 3-centre study (Finland): 50-100 ml blood from pos. BC bottle aspirated onto blood, chocolate and FAA agar plates → incubation 3-4h 37°C CO 2 atmosphere Sample from application area of each plate spread on a MALDI-TOF target plate, even if no visible growth + 1 µl matrix suspension added + air drying → samples analysed in MALDI-TOF instruments Comparison with conventional MALDI-TOF or other identification methods 1 Kalanti A. ECCMID 2014 abs. P0495 2 Østergaard C. ECCMID 2014 abs. P0494 1 of 2 Data from poster

7 MALDI-TOF for pathogen identification in blood cultures (BCs): improved methods MALDI-TOF-MS directly on positive BCs 2 : Single-centre study (2013-2014; Denmark): N=1,068 unique isolates 2 ml blood from pos. BC bottle centrifuged (1,000g; 2 min) to remove RBCs → supernatant centrifuged (14,000g; 10 min) → bacteria in pellet Sample from pellet transferred to MALDI-TOF target plate, without protein extraction + standard matrix added → analysed in MALDI-TOF instrument Comparison with conventional MALDI-TOF (samples cultured on 5% Danish blood or anaerobic agar plates) (cut-off score: 1.7) Short-incubation MALDI-TOF or MALDI-TOF directly on pos. BC bottles may simplify and fasten pathogen identification in BCs 1 Kalanti A. ECCMID 2014 abs. P0495 2 Østergaard C. ECCMID 2014 abs. P0494 2 of 2 Data from poster

8 MALDI-TOF + antimicrobial stewardship team (AST) intervention: impact on outcomes in pts with bloodstream infections (BSIs) Single-centre before-after study (USA): N=501 adult pts with BSI –Pre-intervention phase (Sep-Nov 2011): BSI identified by conventional methods –Intervention phase (Sep-Nov 2012): BSI identified via MALDI-TOF + real-time evidence-based antibiotic recommendations by AST Huang AM et al. Clin Infect Dis 2013;57:1237-45 1 of 2

9 Multivariate analysis for predictors of mortality: Acceptance of AST intervention: trend towards reduced mortality: OR=0.55; 95% CI:0.28-1.06; P=0.075 MALDI-TOF + antimicrobial stewardship team (AST) intervention: impact on outcomes in pts with bloodstream infections (BSIs) MALDI-TOF + AST intervention may decrease time to organism identification and time to effective and optimal antibiotic therapy Huang AM et al. Clin Infect Dis 2013;57:1237-45 2 of 2

10 1,3-β-D-glucan (BG) antigenaemia: accuracy for diagnosing intraabdominal candidiasis (IAC) Fungal Infection Network of Switzerland (FUNGINOS): 2-centre, prospective, observational cohort study (2007-2010): median FU: 19 days N=89 adult ICU pts (≥72h in ICU) with recurrent GI tract perforation (N=68) or acute necrotising pancreatitis (N=21); 920 sera analysed (9 sera/patient) Tissot F et al. Am J Respir Crit Care Med 2013;188:1100-9 1 of 3

11 Mortality/sepsis rate among pts with documented IAC (N=29): Time between microbiological diagnosis of IAC (day 0) and time of reaching value above the cut-off value (per diagnostic method): 1,3-β-D-glucan (BG) antigenaemia: accuracy for diagnosing intraabdominal candidiasis (IAC) Tissot F et al. Am J Respir Crit Care Med 2013;188:1100-9 2 of 3

12 Accuracy (N=29 pts with documented IAC; maximum value up to time of IAC diagnosis compared with day 7 after inclusion in pts without IAC) 1,3-β-D-glucan (BG) antigenaemia: accuracy for diagnosing intraabdominal candidiasis (IAC) In high-risk surgical ICU pts, BG antigenaemia was more accurate than CS and (C)CI and anticipated diagnosis of blood culture-neg. IAC Tissot F et al. Am J Respir Crit Care Med 2013;188:1100-9 3 of 3 *Accuracy=(true positives + true negatives)/ all results; † 2 consecutive BG measurements; (C)CI: (corrected) Candida colonisation index; CS: Candida score; NPV: neg. predictive value; PPV: pos. predictive value


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