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Chapter 4.7 : Commercial Kit Overnight Biochemical Systems for the Identification of Anaerobes
Biochemical systems for identification of an anaerobe rely on the metabolic break-down of substrates and the production of end products during the growth of the isolated organism. There are at least two commercially packaged kit systems that fit this method for the identification of commonly isolated anaerobic bacteria in the clinical microbiology laboratory when species identification is needed: the API 20A (bioMérieux, Inc.) and the AN Microplate (Biolog) ( 1 – 6 ) ( Table 4.7-1 ). Both rely on overnight incubation of the test card before reading. The API 20A is manually filled and read; the AN Microplate is automatically filled but manually (visually) read. The API 20A uses 16 carbohydrates; its indicator system is bromcresol purple that turns yellow at a pH of 6.8 when a positive reaction occurs. The AN Microplate has a database of 361 anaerobes that are exposed to 95 preselected carbon sources for specific identification. The Minitek (BD Biosciences) kit was described in the last two editions of this handbook, but there were no references on the BD website that indicated that these systems were being manufactured any longer. Procedure 4.8 describes the BD Crystal ANR ID, which had largely taken over the role of the older Minitek panels.