[Function and gene expression of the active efflux transporters in drug-resistant Candida albicans].
OBJECTIVE
To investigate the function and gene expression of active efflux transporters in drug-resistant candida albicans.


METHODS
The broth microdilution method was performed to determined the minimal inhibitory concentration of 4 antifungal drugs to 20 candida albicans. We compared the efflux of Rhodamine 6G between sensitive and some of fluconazole-resistant candida albicans, and screened out the resistant strains with significantly increased efflux of Rhodamine 6G. Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to measure the mRNA levels of active efflux gene CDR1 and CDR2.


RESULTS
The efflux of Rhodamine 6G was significantly increased in some fluconazole-resistant strains when glucose was added, and the gene expressions of CDR1 and CDR2 were also obviously increased, compared with those in the sensitive strains.


CONCLUSIONS
The excessive expression of active efflux pump gene is related to the resistance to fluconazole in candida albicans. The measurement of Rhodamine 6G efflux is a useful method for the identification of drug-resistant strains induced by the excessive expression of active efflux pump.
Guo
Hui-Jun
HJ
Department of Microbiology, Xiangya School of Medicine, Central South University, Changsha 410078, China.
Xia
Zhong-di
ZD
Wu
Gao-Li
GL
Zhou
Hui
H
D000935:Antifungal Agents / Q000494:pharmacology; D001692:Biological Transport; D002176:Candida albicans / Q000235:genetics* / Q000502:physiology; D025141:Drug Resistance, Fungal / Q000235:genetics*; D015725:Fluconazole / Q000494:pharmacology; D005656:Fungal Proteins / Q000235:genetics* / Q000502:physiology; D015966:Gene Expression Regulation, Fungal; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000502:physiology; D008826:Microbial Sensitivity Tests; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012235:Rhodamines / Q000378:metabolism
D000935:Antifungal Agents; C094693:CDR1 protein, Candida albicans; D005656:Fungal Proteins; D026901:Membrane Transport Proteins; D012333:RNA, Messenger; D012235:Rhodamines; C026188:rhodamine 6G; D015725:Fluconazole