Rapid identification of Enterobacteriaceae associated with bacteremia: a preliminary report

A preliminary report of a method to rapidly identify Enterobacteriaceae associated with bacteremia is described. When both bottles of a blood culture set revealed gram-negative rods on the Gram stain, an aliquot of the positive culture sample was repeatedly washed in sterile deionized water to remove RBCs and culture media. The concentrated suspension of organisms was used to inoculate API 20ETM identification strips which were generally read within 6-8 hr. Samples were also processed using conventional techniques. Ten episodes of bacteremia associated with Enterobacteriaceae were correctly identified using this rapid system. One Klebsiella pneumoniae with growth only in the aerobic bottle was excluded from the study, but was identified by conventional methods. Further advantages of this protocol are described.