Evaluation of a multitest microtechnique for yeast identification.

A new, multitest, microtechnique system, API 20C (Analytab Products Inc. Clinical Yeast System), was evaluated by comparing it to the U.S. Center for Disease Control (CDC) standard techniques for the identification of yeast. Forty-four yeast strains isolated from clinical specimens were tested by fermentation and assimilation. Six fermentation carbohydrates and ten assimilation carbohydrates were compared. API results were read after incubation of 24 and 48 hours while the standard CDC system was read after 48 hours and 14 days when needed. One hundred per cent agreement in identification was found between the two systems in the strains studied. Growth in the presence of actidione was tested by the API strip only and gave unreliable results with nine per cent of the strains tested. The API 20 Clinical Yeast System provides a reliable and rapid approach to yeast identification enabling the clinical laboratory to completely identify a yeast organism in 48 hours instead of the usual four to 14 days. A cost comparison showed the API system to be significantly more economical than the conventional method of identification.