Evaluation of 10 Tube System for the Identification of Enterobacteriaceae

Uh, Young; Son, Jeong Seog; Hwang, Gyu Yel; Jang, In Ho; Yoon, Kap Jun; Seo, Dong Min

Abstract

BACKGROUND: The selection of identification (ID) system of Enterobacteriaceae depends mainly on accuracy of identification system, cost of operation and convenience of testing. Commercial ID kits are easy to use but too expensive. Therefore, we designed a computerized ID system based on 10 tubes which were composed of 14 conventional biochemical tests to identify the Enterobacteriaceae and Vibrionaceae. The purpose of this present study was to assess the clinical usefulness of 10 tube system as an identification system for Enterobacteriaceae in clinical microbiology laboratories.
METHODS
During the period of January 1998, 189 Enterobacteriaceae and 2 Aeromonas spp. consecutively isolated from clinical specimens were simultaneously identified by 10 tube system and the API rapid ID 32 E. Fourteen conventional biochemical tests used in 10 tube system were lactose, sucrose, and H2S in Kligler's iron agar media; motility, indole, and ornithine decarboxylase in motility-indole-ornithine decarboxylase agar media; citrate, urease, lysine decarboxylase, phenylalanine deaminase, arginine dihydrolase, arabinose, trehalose, and adonitol. Identification program used in 10 tube system were % ID method and ID score method.
RESULTS
Among the 191 isolates, agreement rate of identification between 10 tube system and API rapid ID 32 E were 96.0% to the species level and 99.4% to the genus level. And identification accuracy of 10 tube system was 90.6% to the species level and 93.2% to the genus level.
CONCLUSIONS
10 tube system has been shown to be an accurate, cost-effective alternative to the use of commercial kit systems for identification of Enterobacteriaceae.