Evaluation of germ tube in Candida albicans identification by different media

Abstract

Background: Candida albicans is a common pathogenic, and the germ tube test is one of the identification techniques for this fungal species. Objectives: 1. To experiment with the germ tube test of C. albicans in various media according to the different testing time. 2. To evaluate capacity ofthe germ tube test in C. albicans identification in various media. Methods: This study was carried out with 36 C. albicans isolates and 10 C. tropicalis isolates stored at the Department of Parasitology. Germ tube test was performed using various media, including human sera, 1% peptone medium, BHI broth, egg white, egg yolk, and fetal bovine serum. These experiments were checked after two hours, three hours, and four hours of incubation. Results: The highest rate of germ tube formation of C.albicans was recognized after 3 hours of incubation. The germ tube rates on human serum, 1% peptone medium, egg white, egg yolk, and fetal bovine serum were 91.67%; 58.33%; 25%; 33.33%; 91.67%; and 100%, respectively. The sensitivity, specificity, positive predictive value, and negative predictive value of the germ tube test on serum and egg yolk medium were 91.67%, 100%, 100%, and 76.92%. Conclusions. The capacity to identify C. albicans of the germ tube test performed on fetal bovine serum, human serum and yolk egg could identify 100%, 91.67%, and 91.67%, respectively. It suggested that egg yolk could be used in diagnostic labs as well as mycology researches and training labs to perform germ tube test production to replace human serum since it is a simple and low cost procedure. Key words: Candida albicans, germ tube, fetal bovine serum, yolk egg