Species distribution and antifungal susceptibility of Candida bloodstream isolates in Kuwait: a 10-year study

Abstract

Bloodstream infections due to Candida species are important complications in severely ill hospitalized patients. This study presents data on species distribution and antifungal susceptibility profiles of Candida bloodstream isolates obtained from Kuwait during a 10-year period. All the bloodstream isolates were identified to species level by the germ tube test and carbohydrate assimilation profile using the VITEK 2 yeast identification system. Using E-test strips for amphotericin B, fluconazole, 5-flucytosine and voriconazole, MICs were determined on RPMI agar supplemented with 2% glucose. The MIC breakpoints for resistance were based on Clinical and Laboratory Standards Institute criteria or those published by reference laboratories, and were as follows: amphotericin B, >1 microg ml-1; fluconazole, >or=64 microg ml-1; 5-flucytosine, >or=32 microg ml-1; and voriconazole, 4 microg ml-1. In all, 607 bloodstream yeast isolates were obtained over the past 10 years in Kuwait. Candida albicans was the predominant species (39.5%), followed by Candida parapsilosis (30.6%), Candida tropicalis (12.4%), Candida glabrata (5.6%) and Candida krusei (1.6%). All C. albicans, C. tropicalis and C. glabrata isolates were susceptible to amphotericin B. Of 186 isolates of C. parapsilosis tested, only four (2%) exhibited an MIC for amphotericin B of >1 microg ml-1. Resistance to fluconazole was observed in nine (3.8%) C. albicans isolates, two (5.8%) C. glabrata isolates and four (40%) C. krusei isolates. Resistance to 5-flucytosine was observed in two (0.8%) C. albicans isolates, seven (9.3%) C. tropicalis isolates, three (1.6%) C. parapsilosis isolates and all ten (100%) C. krusei isolates. All the isolates of C. albicans, C. tropicalis, C. parapsilosis, C. glabrata and C. krusei were susceptible to voriconazole, including those resistant to fluconazole. Although amphotericin B and fluconazole are widely used in clinical practice in Kuwait, resistance to these drugs remained low.