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Performance of MALDI Biotyper for Species Identification of Carbapenem-Resistant Enterobacteriaceae by Media Types and Incubation Time
Journal of Laboratory Medicine and Quality Assurance ; : 155-160, 2018.
Artículo en Inglés | WPRIM | ID: wpr-716936
ABSTRACT

BACKGROUND:

This study was conducted to evaluate the impact of the media type used for direct identification of colonies on the surveillance culture of carbapenem-resistant Enterobacteriaceae (CRE) by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS).

METHODS:

CRE surveillance culture isolates were subjected to species identification using the MALDI Biotyper (Bruker Daltonics, Germany) for 2 months starting in March 2017. Four types of media were evaluated blood agar (BA), Mueller Hinton agar (MH), MacConkey agar (Mac), and MacConkey agar containing imipenem of 1 µg/mL (IMP-Mac). CRE-like colonies on IMP-Mac and their subculture colonies on the other media were tested after overnight incubation and extended incubation for one additional day. The percent identification and score value were analyzed for each media types and incubation time when the identification was correct at the genus level.

RESULTS:

A total of 117 isolates were identified as 84 Klebsiella pneumoniae, 12 Escherichia coli, 9 Enterobacter cloacae, 5 Klebsiella oxytoca, 4 Enterobacter aerogenes, and 2 Raoultella ornithinolytica. The successful identification rates (SIR) for BA and MH were 98.3% and 97.4% (P=0.9), respectively, while those for Mac and IMP-Mac were 82.1% (P < 0.001) and 70.9% (P < 0.001), respectively. After extended incubation, SIRs were decreased to 96.6%, 96.6% (P=1.0), 61.5% (P < 0.001), and 58.1% (P < 0.001) on BA, MH, Mac, and IMP-Mac, respectively. The average score values were significantly lower for Mac (2.017±0.22) and IMP-Mac (1.978±0.24) than for BA (2.213±0.16) (P < 0.001).

CONCLUSIONS:

The low performance of the MALDI Biotyper applied directly to the colonies grown on Mac or IMP-Mac indicates that subculture on BA or MH is preferable before identification by MALDI-TOF MS.
Asunto(s)

Texto completo: Disponible Índice: WPRIM (Pacífico Occidental) Asunto principal: Espectrometría de Masas / Imipenem / Enterobacter cloacae / Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción / Enterobacter aerogenes / Klebsiella oxytoca / Agar / Enterobacteriaceae / Escherichia coli / Klebsiella pneumoniae Tipo de estudio: Estudio diagnóstico / Estudio pronóstico Idioma: Inglés Revista: Journal of Laboratory Medicine and Quality Assurance Año: 2018 Tipo del documento: Artículo

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Texto completo: Disponible Índice: WPRIM (Pacífico Occidental) Asunto principal: Espectrometría de Masas / Imipenem / Enterobacter cloacae / Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción / Enterobacter aerogenes / Klebsiella oxytoca / Agar / Enterobacteriaceae / Escherichia coli / Klebsiella pneumoniae Tipo de estudio: Estudio diagnóstico / Estudio pronóstico Idioma: Inglés Revista: Journal of Laboratory Medicine and Quality Assurance Año: 2018 Tipo del documento: Artículo