Identification and Biochemical Reactions of Enterococci by a Simplified Identification System

Uh, Young; Jang, In Ho; Hwang, Gyu Yel; Yoon, Kap Jun; Lee, Hyung Hoan

Abstract

BACKGROUND: The accurate and rapid identification of enterococci can provide clinician's decision making of antimicrobial therapy because enterococci are usually multiresistant to commonly used antimicrobial agents and antimicrobial resistance patterns are different according to enterococcal species. Accuracy of identification system depends mainly on data base such as positive rate of biochemical reactions, relative frequency of occurrence of biotype, and isolation frequency of microorganisms. The purpose of this study was to analyze the isolation rate and biotype frequency of enterococci isolated from clinical specimens.
METHODS
We used a simplified identification system for the identification of the enterococci from clinical specimens during the period of June 1998 to November 1998. Biochemical phenotypes of 500 isolates of enterococci were also analyzed by a simplified identification system consisting of eight conventional biochemical tests.
RESULTS
Enterococci were isolated from urine (36.4%), wound (35.0%) and blood (7.2%) in order of decreasing frequency. Among the isolates, 67.8% were E. faecalis, 23.0% E. faecium, 2.2% E. hirae/durans, 2.0% E. casseliflavus, and 1.0% E. hirae. The simplified identification system of enterococci identified 93.6% of all isolates to species level. The system identified 98.5% of E. faecalis but only 89.6% of E. faecium.
CONCLUSIONS
Our simplified identification system based on eight biochemical tests offer a simple, reliable and economic method for the identification of clinical isolates of enterococci, but further studies are needed for the improvement of accuracy and identification rate.