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


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Comparison of EASY 24 Plus, API 20E, and VITEK GNI+ for Identification of Enterobacteriaceae

Original article

Annals of Clinical Microbiology (Ann Clin Microbiol) 2001 December Volume 4, Issue 2, pages 96-101.

Comparison of EASY 24 Plus, API 20E, and VITEK GNI+ for Identification of Enterobacteriaceae

Mi Ae Lee, M.D., Hyang Sook Park, M.T., Sunjoo Kim, M.D.*, and Eui Chong Kim, M.D.**

Department of Clinical Pathology, College of Medicine, Ewha Womans University Mokdong Hospital, Seoul, Korea, Department of Clinical Pathology, Gyeongsang National Univeresity, Chinju, Korea*, and Department of Clinical Pathology, Seoul National University College of Medicine, Seoul, Korea**


Background:Several automated and nonautomated systems have been developed and are commercially available for the identification of gram-negative bacilli. EASY 24E+ kit was recently developed as Korean kit for identification of gram-negative bacilli. So we evaluated the accuracy and clinical utility of EASY 24E+ compared with API 20E and VITEK GNI+.

Methods:The 221 clinical isolates of Enterobacteriaceae, including 17 C. freundii, 20 E. cloacae, 31 E. coli, 6 E. aerogenes, 29 K. pneumoniae, 3 K. oxytoca, 11 M. morganii, 13 P. mirabilis, 16 Salmonella  spp., 20 S. marcescens, 9 Shigella spp.,22 S. sonnei, 16 S. typhi, 8 Y.  pseudotuberculosis and 10 control strains were identified by API 20E, EASY 24E+, and VITEK GNI+. Discrepant strains were performed repeat identifications and we evaluated overall accuracy.

Results:All of control strains were correctly identified by three systems. The overall correct results at species level and at the genus level for 221 clinical isolates, were 96.8% and 99.1% by the VITEK GNI+, 97.7% and 97.7% by the EASY 24+ and 99.1% and 100% by the API 20E. All of Salmonella spp., S. typhi and Shigella spp. were correctly identified by all three systems and the discrepant identifications of species were 2 Y. pseudotuberculosis, 3  K. pneumoniaeand 2 K. oxytoca by VITEK GNI+, 4 C. freundii and 1 P. mirabilis by EASY 24+, and 2 S. marcescens by API 20E.

Conclusions:All three identification systems are accurate methods for the identification of Enterobacteriaceae, and EASY 24+ is comparable with API 20E and VITEK GNI+. (Korean J Clin Microbiol 2001;4(2):96-101)


 Identification, Enterobacteriaceae, Salmonella spp., Shigella, EASY 24+