Detection of Candida albicans from Positive Blood Culture Bottles

Abstract

Objective: To determine the efficacy of direct germ tube method in early detections of candida albicans.
Introduction: Blood stream infections (BSIs) caused by Candida species are on the increase and associated
with high mortality rates, which are due in part to delay in the administration of appropriate antifungal
therapy. Earlier identification of yeast isolates from blood cultures may improve clinical outcomes.
Identification of Candida as albicans or non-albicans species depends on the presence or absence
of germ tubes. Rapid differentiation of C.albicans from non- albicans is made on its ability to produce
germ tubes after incubation in human serum.
Materials and Methods: Germ tube test (GTT) is performed on colonies grown on agar plate after 24–
48 h of incubation. In our study, we performed GTT directly on the aliquot taken from positive blood
culture bottles and yeast cells seen in Gram stain. The results were compared with GTT using the conventional
method.
Results: Out of 100 positive blood cultures with yeast like cells on gram stain only eight were positive
for Candida albicans by both the methods. There was 100 % concordance between the direct GTT and the
GTT performed from the subcultured organisms grown on solid media.
Conclusion: Early detection of species of Candida using the Direct Germ Tube method is of utmost
importance for early initiation of appropriate anti-fungal therapy in order to reduce morbidity and
mortality of patients with candidemia.