Abstract:
Invasive infections caused by yeasts are associated with high mortality and morbidity, and resistance to antifungal agents is increasing. Candida
spp. has emerged as the leading cause of systemic nosocomial fungal infections. The aim of this study was to identify yeast isolates from sterile site
specimens to species level, and to determine their susceptibility to fluconazole and voriconazole, at the National Health Laboratory, Service Dr George
Mukhari Tertiary Laboratory from March to August 2007. Candida isolates were identified to species level using a germ tube test and/or Api® ID 32C
kits. Antifungal susceptibility testing to fluconazole and voriconazole was performed using the disc diffusion method in accordance with the Clinical
and Laboratory Standards Institute guidelines. All of the Candida isolates were from the neonatal intensive care unit (NICU), with the exception of two.
The distribution of yeast isolates was as follows: C. krusei (41.9%), C. albicans (32.3%), C. inconspicua (5.5%), C. parapsilosis (2%), C. tropicalis (1.5%),
C. sake (1.5%), C. lambica (1.5%), and C. valida (0.5%). Cryptococcus neoformans (11%), C. albidus (0.5%), Rhodotorula glutinis (1%), and C. humicola
(0.5%) were also isolated. Of the isolated C. albicans, 61% were susceptible to fluconazole. A possible C. krusei outbreak could have occurred in the
NICU during the study period. Voriconazole was the most susceptible antifungal agent to various yeast pathogens. The results of this study on azoles
susceptibility testing of yeasts show that voriconazole may prove to be a valuable alternative antifungal agent in this tertiary hospital for the treatment
of infections caused by yeasts, including Candida spp.
