Annals of Clinical Microbiology, The official Journal of the Korean Society of Clinical Microbiology


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Indexed in KCI, KoreaMed, Synapse, DOAJ
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pISSN 2288-0585 eISSN 2288-6850

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

Original article

Annals of Clinical Microbiology (Ann Clin Microbiol) 2010 December, Volume 13, Issue 4, pages 157-161.

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

Mi Kyung Kim, Jong Hee Hong, Miae Lee

Department of Laboratory Medicine, Ewha Womans University School of Medicine, Seoul, Korea


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 (bioMérieux, 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 D- zone 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. (Korean J Clin Microbiol 2010;13:157-161)


 Inducible clindamycin resistance, Staphylococcus aureus, VITEK2