Korean J Clin Microbiol.  2010 Dec;13(4):157-161. 10.5145/KJCM.2010.13.4.157.

Performance of the VITEK2 System for Detection of Inducible Clindamycin Resistance in Staphylococci

• Kim MK
• Hong JH
• Lee M

• KMID: 1461610
• DOI: http://doi.org/10.5145/KJCM.2010.13.4.157

Abstract

BACKGROUND
The Clinical and Laboratory Standards Institute (CLSI) recommends testing for inducible clindamycin resistance in clindamycin non-resistant and erythromycin resistant (CNR-ER) staphylococci by using a D-zone test. Recently, the VITEK2 system was developed to detect inducible clindamycin resistance in staphylococci. We evaluated the performance of the VITEK2 system by comparing it with a D-zone test.
METHODS
In detecting inducible clindamycin resistance, a total of 142 clinical isolates of staphylococci were tested by using the VITEK2 Antimicrobial Susceptibility Test (AST)-P601 card (bioMerieux, Marcy l'Etoile, France) and the D-zone test. Of the 142 isolates of staphylococci tested, 114 were CNR-ER staphylococci [40 coagulase-negative staphylococci (CoNS), 74 Staphylococcus aureus] and 28 were staphylococci, either resistant or susceptible to clindamycin and erythromycin (1 CoNS and 27 S. aureus).
RESULTS
Of the 114 CNR-ER staphylococci, 98.6% (73/74) of S. aureus and 32.5% (13/40) of CoNS were inducible clindamycin resistant according to the Dzone test. Overall sensitivity and specificity of the VITEK2 system were 98.8% (85/86) and 98.2% (55/56) respectively, and the agreement between the VITEK2 system and the D-zone test was 98.6% (140/142).
CONCLUSION
The VITEK2 system shows high concordance with a D-zone test. The inducible clindamycin resistance in staphylococci can be detected easily and conveniently by the VITEK2 system.

Keyword

Inducible clindamycin resistance; Staphylococcus aureus; VITEK2

MeSH Terms

Clindamycin
Erythromycin
Sensitivity and Specificity
Staphylococcus
Staphylococcus aureus
Clindamycin
Erythromycin

Figure

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  Fig. 1. Inducible clindamycin resistance positivity by the D-zone test. Arrow, blunting of inhibitory zone of clindamycin; C, clindamycin; E, erythromycin.

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