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Eur J Clin Microbiol Infect Dis. 2018 Aug;37(8):1573-1583. doi: 10.1007/s10096-018-3287-6. Epub 2018 May 28.

Evaluation of the Accelerate Pheno™ system for rapid identification and antimicrobial susceptibility testing of Gram-negative bacteria in bloodstream infections.

Author information

1
Hospices Civils de Lyon, Groupement Hospitalier Nord, Microbiology Laboratory, Institute for Infectious Agents, Lyon, France. ghislaine.descours@univ-lyon1.fr.
2
Inserm, U1111, CNRS, UMR5308, École Normale Supérieure de Lyon, Université Lyon 1, Lyon, France. ghislaine.descours@univ-lyon1.fr.
3
Université Lyon 1, Lyon, France. ghislaine.descours@univ-lyon1.fr.
4
Hospices Civils de Lyon, Groupement Hospitalier Nord, Microbiology Laboratory, Institute for Infectious Agents, Lyon, France.
5
Department of Hygiene, Centre Léon Bérard, Lyon, France.
6
Inserm, U1111, CNRS, UMR5308, École Normale Supérieure de Lyon, Université Lyon 1, Lyon, France.
7
Université Lyon 1, Lyon, France.

Abstract

Identification and antimicrobial susceptibility testing (AST) are critical steps in the management of bloodstream infections. Our objective was to evaluate the performance of the Accelerate Pheno™ System, CE v1.2 software, for identification and AST of Gram-negative pathogens from positive blood culture bottles. A total of 104 bottles positive for Gram-negative bacteria collected from inpatients throughout our institution were randomly selected after Gram staining. The time-to-identification and AST results, and the raw AST results obtained by the Accelerate Pheno™ system and routine techniques (MALDI-TOF MS and VITEK®2, EUCAST guidelines) were compared. Any discrepant AST result was tested by microdilution. The Pheno™ significantly improved turn-around times for identification (5.3 versus 23.7 h; p < 0.0001) and AST (10.7 versus 35.1 h; p < 0.0001). Complete agreement between the Accelerate Pheno™ system and the MALDI-TOF MS for identification was observed for 96.2% of samples; it was 99% (98/99) for monomicrobial samples versus 40% (3/5) for polymicrobial ones. The overall categorical agreement for AST was 93.7%; it was notably decreased for beta-lactams (cefepime 84.4%, piperacillin-tazobactam 86.5%, ceftazidime 87.6%) or Pseudomonas aeruginosa (71.9%; with cefepime 33.3%, piperacillin-tazobactam 77.8%, ceftazidime 0%). Analysis of discrepant results found impaired performance of the Accelerate Pheno™ system for beta-lactams (except cefepime) in Enterobacteriales (six very major errors) and poor performance in P. aeruginosa. The Accelerate Pheno™ system significantly improved the turn-around times for bloodstream infection diagnosis. Nonetheless, improvements in the analysis of polymicrobial samples and in AST algorithms, notably beta-lactam testing in both P. aeruginosa and Enterobacteriales, are required for implementation in routine workflow.

KEYWORDS:

Accelerate Pheno™ system; Antimicrobial susceptibility testing; Bacteremia; Bloodstream infections; Gram-negative bacteria; Sepsis

PMID:
29808350
DOI:
10.1007/s10096-018-3287-6
[Indexed for MEDLINE]

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