Species Identification of Candida Isolates from Critically Ill Patients by Rapid Commercial and Genotypic Methods

Abstract

Background: Rapid, reliable Candida species (spp.) identification is crucial because it enables prompt and effective antifungal treatment. Unfortunately this is difficult due to a lack of knowledge, adequate reagents, and equipments, particularly in countries with limited resources. Objectives: The aim of this study was to assess the effectiveness of rapid commercial methods in identifying Candida spp. isolated from critically ill patients. Methodology: Various clinical specimens were collected from critically ill patients admitted to the Intensive Care Units of Mansoura University Hospitals, and processed by numerous mycological techniques. Gram stained, and lactophenol cotton blue stained films, as well, germ tube test, and corn meal agar with 1% Tween 80 were used to identify the isolated Candida spp. Three commercial methods were used for spp. identification; CHROMagar TM Candida medium, API 20 C AUX and Vitek-2 Compact automated system. In addition, all Candida isolates were subjected to species-specific multiplex PCR as the reference method. Results: A total of 52 Candida strains were identified where C. albicans was the predominant spp. (53.8%) followed by C. parapsilolsis (17.3%), C. glabrata (13.5%), C. dubliniensis (5.8%), C. tropicalis (5.8%), C. auris (1.9%) and C. krusei (1.9%). Both CHROMagar TM Candida medium and Vitek-2 Compact automated system exhibited high sensitivity and specificity rates in identification of various Candida spp. as compared to multiplex PCR. Conclusion: This study demonstrated a good performance of both CHROMagar TM Candida medium and Vitek-2 Compact automated system; however, CHROMagar TM Candida medium may be an easier and more cost-effective choice to identify Candida spp., mainly in areas with restricted resources.