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Park, Song, Kim, Kim, Kim, and Lee: Evaluation of the Vitek 2 AST-N055 Card for the Susceptibility Testing of Acinetobacter baumannii Isolates to Amikacin
Original Article

Korean J Clin Microbiol 2009;12(3):144-145.

Published online: 22 September 2009

DOI: https://doi.org/10.5145/KJCM.2009.12.3.144

Evaluation of the Vitek 2 AST-N055 Card for the Susceptibility Testing of Acinetobacter baumannii Isolates to Amikacin

Dong-Jin Park1, Wonkeun Song1, Taek-Kyung Kim2, Jae-Seok Kim1, Han-Sung Kim1, Kyu Man Lee1

1Department of Laboratory Medicine, Hallym University College of Medicine, Seoul, Korea

2Kangnam Sacred Heart Hospital, Seoul, Korea

Correspondence: Wonkeun Song, Department of Laboratory Medicine, Hallym University College of Medicine, 948-1, Daerim 1-dong, Youngdeungpo-gu, Seoul 150-950, Korea. (Tel) 82-2-829-5259, (Fax) 82-2-847-2403, (E-mail) swonkeun@hallym.or.kr

Received 12 May 200917 August 2009       Accepted 25 August 2009

Copyright © 2009 Korean Journal of Clinical Microbiology

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We collected 76 clinical isolates of Acinetobacter baumannii (amikacin MIC by Vitek 2 AST-N055 card: ≤2μg/mL, 11 isolates; 4μg/mL, 19 isolates; 8μg/ mL, 17 isolates; 16μg/mL, 27 isolates; and ≥64μg/ mL, 2 isolates) from a university hospital and evaluated the Vitek 2 AST-N055 card vs the broth microdilution as a reference method for testing susceptibility to amikacin. Vitek 2 AST-N055 card yielded very major errors in 15 isolates (19.7%) and minor errors in 26 isolates (34.2%). Of the 15 isolates shown very major errors, 14 had Vitek 2 MICs ranging from 8 to 16μg/mL. The results of our study suggest strongly that it is unreliable to test the amikacin susceptibility by Vitek 2 AST-N055 card of A. baumannii with the Vitek 2 MICs ranging from 8 to 16μg/mL. In those cases, another susceptibility test, such as broth microdilution (BMD), should be performed to confirm the results.

Keywords: Amikacin, Acinetobacter baumannii, Vitek 2

REFERENCES

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crossref

Table 1.
Comparison of broth microdilution method and Vitek 2 AST-N055 card for amikacin susceptibility testing of 76 A. baumannii isolates
Category (MIC, μg/mL) No. of isolates
Broth microdilution Vitek 2
R (≥512) S (16) 1
R (128) R (≥64) 2
R (128) S (16) 1
R (64) S (16) 7
R (64) S (8) 5
R (64) S (4) 1
I (32) S (16) 12
I (32) S (8) 7
I (32) S (4) 7
S (16) S (16) 6
S (16) S (8) 3
S (16) S (4) 10
S (8) S (8) 2
S (8) S (4) 1
S (8) S (≤2) 5
S (4) S (≤2) 6
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