Evaluation of the R-B System for the Identification of Enterobacteriaceae

Abstract

Four hundred fifteen clinical isolates of Enterobacteriaceae were identified by conventional methods and by the R-B system. There was complete agreement between the two methods with 412 (99%) of these isolates. There was also agreement with eleven stock cultures of Salmonella, Arizona, and Shigella. The times required to inoculate and identify the isolates with the two systems were similar. The motility reaction in the R-B system was not reliable, but false-negative reactions did not result in incorrect identification of the organisms. Occasional false-negative phenylalanine deaminase and indole tests were noted. The authors conclude that the R-B system is an acceptable alternative to the other methods employed in this study for identification of Enterobacteriaceae.