Enterosistem 18-R: description and comparative evaluation with conventional methods for identification of members of the family Enterobacteriaceae.

The efficiency and accuracy of Enterosistem 18-R (Liofilchem s.r.l., Roseto degli Abruzzi, Teramo, Italy) were compared with those of conventional biochemical methods to identify 360 members (38 species) of the family Enterobacteriaceae. Overall, 329 strains (91.3%) were correctly identified (percentage of identification, greater than or equal to 90.0), with 37 (11.2%) requiring additional tests for complete identification. For 11 isolates (3.1%), Enterosistem 18-R gave only genus identifications, and for 14 (3.9%), the strains did not correspond to any key in the codebook and could not be identified by the manufacturer's computer service. Only six isolates (1.7%) were misidentified. The new system accurately identified common and several newly described isolates of the family Enterobacteriaceae, such as Enterobacter gergoviae, Providencia rustigianii, Serratia odorifera, and Serratia rubidaea. The system is highly reproducible, simple to perform, easy to handle, and inexpensive. With adjustments in supplementary code numbers for some strains, Enterosistem 18-R is a suitable alternative for identification of members of the Enterobacteriaceae in clinical laboratories.