Species-Specific Differences in Rhodamine 6G Accumulation of Candida Isolates Detected by Flow Cytometric Analysis.
10.3343/kjlm.2009.29.2.127
- Author:
Chang Jin MOON
1
;
Jong Hee SHIN
;
Da Woon KIM
;
Seung Jung KEE
;
Soo Hyun KIM
;
Myung Geun SHIN
;
Soon Pal SUH
;
Dong Wook RYANG
Author Information
1. Department of Laboratory Medicine, Chonnam National University Medical School, Gwangju, Korea. shinjh@chonnam.ac.kr
- Publication Type:Original Article ; English Abstract
- Keywords:
Candida;
Flow cytometry;
Rhodamine 6G;
Azole resistance;
Mechanism
- MeSH:
Antifungal Agents/pharmacology;
Azoles/pharmacology;
Candida/chemistry/isolation & purification/*metabolism;
Candidiasis/drug therapy;
Drug Resistance, Fungal;
Flow Cytometry/*methods;
Fluconazole/pharmacology;
Fluorescent Dyes/*analysis;
Humans;
Microbial Sensitivity Tests;
Rhodamines/*analysis;
Species Specificity
- From:The Korean Journal of Laboratory Medicine
2009;29(2):127-134
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
BACKGROUND: Fluorescent dye Rhodamine 6G (R6G) is a substrate of multidrug resistance pumps and its accumulation is reduced in some azole-resistant Candida isolates with the upregulation of multidrug efflux transporter genes. Despite reports on species-specific differences in azole susceptibility in various Candida species, only a few studies have been reported on the R6G accumulation among clinical isolates of Candida species. In this study, we compared R6G accumulation between six different Candida species. METHODS: The intracellular accumulation of R6G and minimal inhibitory concentrations (MICs) of three triazole agents were investigated in 48 strains of six Candida species (14 C. albicans, 9 C. tropicalis, 8 C. glabrata, 8 C. krusei, 7 C. parapsilosis, and 2 C. haemulonii). R6G accumulation was measured by using flow cytometry and the geometric mean of the fluorescence intensity (GMF) was used to compare the accumulation between the Candida isolates. RESULTS: The GMF values for the C. tropicalis, C. albicans, C. krusei, C. parapsilosis, and C. glabrata isolates were 167.3+/-18.5, 126.9+/-6.6, 88.5+/-18.5, 50.8+/-7.0, and 38.1+/-3.9, respectively. C. glabrata had a significantly lower mean GMF than all the other Candida species (P<0.05). While some Candida strains with trailing growth phenomenon and increased fluconazole MIC did not have a reduced GMF, three Candida strains with increased MICs to all three triazole agents had a reduced GMF. CONCLUSIONS: This study found species-specific differences in R6G accumulation in Candida. In addition, the intracellular R6G accumulation can be used to investigate the drug efflux mechanism in azole-resistant Candida strains.
