White-opaque Switching in Different Mating Type-like Locus Gene Types of ClinicalCandida albicansIsolates.
BACKGROUND
Candida albicans (C. albicans) can become a pathogen causing superficial as well as life-threatening systemic infections, especially in immunocompromised patients. Many phenotypic attributes contribute to its capacity to colonize human organs. In our study, 93 C. albicans isolates from patients of various candidiasis in a hospital of China were surveyed. We aimed to investigate the white-opaque (WO) switching competence, drug sensitivity, and virulence of mating type-like (MTL) a/α isolates.


METHODS
Internal transcribed spacer (ITS) gene and the MTL configuration were detected in all the isolates by reverse transcription-polymerase chain reaction. White/opaque phenotype and doubling time of cell growth were determined. The minimum inhibitory concentrations of antifungal agent were measured using broth microdilution method.


RESULTS
Sixty-four isolates (69.6%) were classified to serotype A, 19 (20.6%) to serotype B, and 9 (9.8%) to serotype C. Moreover, phylogenetic analysis showed that these isolates were divided into four different subgroups of ITS genotypes. Most of our clinical isolates were MTL a/α type, while 6.8% remained MTL a or MTLα type. The frequency of opaque phenotype was 71.0% (66 isolates). Following the guidelines of Clinical and Laboratory Standards Institute M27-A3, all isolates were susceptible to caspofungin and a few (0.6-3.2%) of them showed resistance against amphotericin B, flucytosine, fluconazole, itraconazole, and voriconazole.


CONCLUSIONS
From these analyses, there were comparatively more C. albicans strains classified into serotype B, and the frequency of opaque phase strains was significant in the clinical isolates from China. Genetic, phenotypic, or drug susceptibility patterns were not significantly different from previous studies. MTL a/α isolates could also undergo WO switching which facilitates their survival.
Department of Dermatology, Peking University People's Hospital, Beijing 100044, China.
Hou-Min
HM
Li
Medical Mycology Research Center, Chiba University, Chiba 260-8673, Japan, japan.
Yumi
Y
Shimizu-Imanishi
Medical Mycology Research Center, Chiba University, Chiba 260-8673, Japan, japan.
Reiko
R
Tanaka
Department of Dermatology, Peking University First Hospital, Beijing 100034, China.
Ruo-Yu
RY
Li
Medical Mycology Research Center, Chiba University, Chiba 260-8673, Japan, japan.
Takashi
T
Yaguchi
D000666:Amphotericin B / Q000494:pharmacology; D000935:Antifungal Agents / Q000494:pharmacology*; D002176:Candida albicans / Q000145:classification / Q000187:drug effects / Q000235:genetics*; D015725:Fluconazole / Q000494:pharmacology; D005838:Genotype; D006801:Humans; D008826:Microbial Sensitivity Tests; D010802:Phylogeny
D000935:Antifungal Agents; D000666:Amphotericin B; D015725:Fluconazole