Evaluation of two BBL Crystal systems for identification of some clinically important gram-negative bacteria.
The BBL Crystal system (Becton Dickinson Microbiology Systems, Cockeysville, Md.) is a miniaturized bacterial identification method employing modified conventional and chromogenic substrates. Two products are currently available, the Rapid Stool/Enteric ID Kit and the Enteric/Nonfermenter ID Kit, each comprising thirty tests. We report an evaluation of both systems (using database version 1.1 for both) in the identification of 51 gram-negative taxa likely to be encountered commonly in the clinical laboratory. In all, 266 strains were tested in the Enteric/Nonfermenter ID Kit, and these represented 36 taxa of the family Enterobacteriaceae (188 strains), 5 oxidase-positive fermentative taxa (26 strains), and 10 nonfermentative taxa (52 strains). The majority of these same strains (203 of 266) were also tested in the Rapid Stool/Enteric ID Kit. The Enteric/Nonfermenter ID Kit performed as follows: Enterobacteriaceae, 93% correct, 6% not identified, and 1% incorrect; oxidase-positive fermenters, 88, 12, and 0%, respectively; and nonfermenters, 100% correct, although several only to the genus or group level. The Rapid Stool/Enteric ID Kit gave the following results: Enterobacteriaceae, 91% correct, 7% not identified, and 2% incorrect; oxidase-positive fermenters, 80, 13, and 7%, respectively (but results were based on only 15 strains); and nonfermenters, 100% correct (but results were based on only 11 strains). We found the systems extremely easy and rapid to use, and for the Enteric/Nonfermenter ID Kit an identification rate of 100% in 40 of 51 taxa was achieved, with corresponding figures of 29 of 39 taxa for the Rapid Stool/Enteric ID Kit.
Holmes
B
B
National Collection of Type Cultures, Central Public Health Laboratory, London, England.
Costas
M
M
Thaker
T
T
Stevens
M
M
D001431:Bacteriological Techniques / Q000295:instrumentation; D002863:Chromogenic Compounds; D004755:Enterobacteriaceae / Q000302:isolation & purification / Q000378:metabolism; D005069:Evaluation Studies as Topic; D005243:Feces / Q000382:microbiology; D005285:Fermentation; D006090:Gram-Negative Bacteria / Q000145:classification / Q000302:isolation & purification* / Q000378:metabolism; D006801:Humans; D009391:Nephelometry and Turbidimetry; D011933:Reagent Kits, Diagnostic; D013045:Species Specificity
D002863:Chromogenic Compounds; D011933:Reagent Kits, Diagnostic