Species distribution and in-vitro antifungal susceptibility pattern of Candida clinical isolates

Abstract

BACKGROUND: An increase in incidence of Candida infections and isolation of resistant isolates were common occurrences in recent years due to increase in immunocompromised patients and advances in medical field. OBJECTIVES: To determine the Candida species isolated from various clinical specimens received at the Department of Mycology, Medical Research Institute from 08/08/14 - 25/10/14 and to determine their antifungal susceptibility pattern for commonly used antifungals in Sri Lanka. METHODS: Identification of 90 clinical isolates was done by using conventional methods of Candida identification and API kits. In-vitro antifungal susceptibility pattern of isolates to fluconazole, amphotericine B, ketoconazole, itraconazole, miconazole, nystatin, clotrimazole and voriconazole were determined according to CLSI M44A. RESULTS: Candida tropicalis (37.7%) was the most frequently isolated species, followed by C.albicans (36.6%), C.parapsilosis (24.4%) and C.krusei (1.1%). C.tropicalis was the predominant isolate from blood, sterile fluids and urine specimens. Majority of the isolates from scraping specimens were C.parapsilosis while C.albicans was the commonest in respiratory specimens. Variations in resistance were seen, depending on the species and the respective type of specimens. All Candida isolates were sensitive to amphotericin B. Twenty-three (24.44%) fluconazole resistant isolates were detected from blood, urine, pus, sterile fluids and respiratory and scraping specimens. Variable sensitivity patterns were observed for voriconazole, miconazole, itraconazole, ketoconazole, nystatin and clotrimazole. CONCLUSIONS: All clinical yeast isolates should be identified up to species level and antifungal susceptibility testing should be performed to prevent therapeutic failures. Resistance to fluconazole, is an alarming sign for emerging antifungal resistance in Sri Lanka.