Different reading time intervals of the API 20C AUX® system for identifying the yeasts of medical interest

Abstract

Bloodstream infections due to Candida genus are one of the leading cause of morbidity and mortality in immunocompromised patients. Candida albicans remains to be the yeast species which is the most commonly isolated in these infections. This species is easily and rapidly identified. However there are other species such as Candida parapsilosis, C. tropicalis, C. glabrata and C. krusei, which are of lower frequency and they take longer to be detected; and commercially available automated or semi-automated methodologies are needed for their identification. Hundred forty-six yeast strains were analyzed for evaluating the capability of the API 20C AUX® system (Biomerieux®, France) for correctly identifying the microorganism genus and specie in different reading periods of time, and to release the final results in less time. C. parapsilosis, C. guilliermondii, Candida pelliculosa, C. colliculosa, Rhodotorula mucilaginosa, Saccharomyces cerevisae, Trichosporon mucoides and T. asahii were the yeasts released in times of 96, 120 and 144 h. Eighty percent of C. glabrata and 69 % of C. tropicalis were also identified in periods beyond the established time. With the achieved results, it is feasible to anticipate the identification of the gender and of some yeast species.