Rapid differentiation of Candida albicans from non-albicans species by germ tube test directly from BacTAlert blood culture bottles

Authors


Jolanta Terlecka, Department of Microbiology, Alfred Hospital, Melbourne 3004, Vic., Australia.
Tel.: (03) 92763059. Fax: (03) 927 62227. E-mail: j.terlacka@alfred.org.au

Summary

Bloodstream infections (BSIs) caused by Candida species are increasing in incidence, and are associated with high mortality rates, which are due in part to a delay in the administration of appropriate antifungal therapy. Earlier identification of yeast isolates from blood cultures may improve clinical outcomes. Identification of a Candida as albicans or non-albicans species depends on the presence or absence of germ tubes. Conventionally, germ tube test (GTT) is performed on colonies grown on agar plate after 24–48 h of incubation. In the present study, the GTT was performed earlier on an aliquot taken from blood culture bottle, after yeast cells were seen in Gram stain and the results were compared with the GTT using the conventional method. Thirty-one consecutive bloodstream isolates of yeast were included in this prospective study over 10 months. There was 100% concordance between the two GTT methods. Final identification was confirmed by standard laboratory procedures. The performance of GTT directly from blood culture bottles has important implications for early, appropriate therapy in patients with candidaemia.

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