26 API-20E Tests
26.1 Using an API-20E test for the identification of Escherichia, Salmonella, and Shigella sp.
This diagnostic test uses 21 miniaturised biochemical tests and a database to identify an unknown microorganism that is suspected of being a member of the Enterobacteriaceae. Tests are grouped together in units of three and individual tests have a value of 1, 2 or 4 associated with them (Figure 26.1). By adding the values corresponding to positive reactions within each group, a 7-digit code (Analytical Profile Index) is generated that should reference a specific microorganism in the manufacturer’s database. The database also gives an indication of the confidence of the result.
Because of the long time between two laboratory sessions in this course (2 weeks), we are unable to perform the API-20E test during this lab (instead, this experiment has been performed for you and the results posted for you).
