Molecular epidemiology and antifungal susceptibility of Candida parapsilosis sensu stricto, Candida orthopsilosis, and Candida metapsilosis in Taiwan.
Candida parapsilosis was recently reclassified into 3 closely related species, C. parapsilosis sensu stricto, Candida orthopsilosis, and Candida metapsilosis. Variation in susceptibility characteristics and prevalence of the 3 genomic species could have therapeutic and epidemiologic implications. The aim of this study is to characterize the genetic and antifungal susceptibility profiles of 97 C. parapsilosis isolates from 71 patients. Among the 71 nonduplicate isolates, 85.9% (61/71) were identified as C. parapsilosis sensu stricto, 5.6% (4/71) as C. metapsilosis, and 8.5% (6/71) as C. orthopsilosis species based on sequences of the internal transcribed spacer (ITS) region. The delineation of these 3 species is concordant with that achieved by pulsed-field gel electrophoresis of BssHII restriction fragments at 75% similarity. Antifungal susceptibility tests showed that most isolates were susceptible to flucytosine, azoles, amphotericin B, and echinocandins, whereas 3 C. metapsilosis isolates from 1 patient showed resistance and susceptible-dose dependence to fluconazole. The C. metapsilosis isolates exhibited significantly higher MIC values to both fluconazole and voriconazole than those of C. parapsilosis sensu stricto and C. orthopsilosis. On the other hand, the C. metapsilosis isolates showed significantly lower MIC values on 24 h to caspofungin than those of C. parapsilosis sensu stricto and C. orthopsilosis. For micafungin, the isolates of C. parapsilosis sensu stricto had significantly higher MIC values on 24 h than those of C. orthopsilosis and C. metapsilosis. Compared to Candida albicans, mutations from proline to alanine were identified on the hot spot 1 of Fks1 in all these C. parapsilosis sensu lato isolates regardless of their MIC levels. Some of the C. orthopsilosis and C. metapsilosis isolates expressed the isoleucine to valine substitution on the hot spot 2 region. However, the amino acid variations in these isolates did not correlate to their MIC values of echinocandin.
Chen
Yee-Chun
YC
Division of Infectious Diseases, Departments of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
Lin
Yu-Hsin
YH
Chen
Kuo-Wei
KW
Lii
Joanne
J
Teng
Hwa-Jen
HJ
Li
Shu-Ying
SY
D000818:Animals; D000935:Antifungal Agents / Q000494:pharmacology*; D002175:Candida / Q000145:classification* / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D002177:Candidiasis / Q000453:epidemiology* / Q000382:microbiology*; D016000:Cluster Analysis; D016172:DNA Fingerprinting; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics; D005964:Glucosyltransferases / Q000235:genetics; D006801:Humans; D008826:Microbial Sensitivity Tests; D017720:Molecular Epidemiology; D016533:Mycological Typing Techniques; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D013624:Taiwan / Q000453:epidemiology
D000935:Antifungal Agents; D004271:DNA, Fungal; D021903:DNA, Ribosomal Spacer; D005656:Fungal Proteins; D005964:Glucosyltransferases