Candida nivariensis, an emerging pathogenic fungus with multidrug resistance to antifungal agents.
In 2005, Candida nivariensis, a yeast species genetically related to Candida glabrata, was described following its isolation from three patients in a single Spanish hospital. Between 2005 and 2006, 16 fungal isolates with phenotypic similarities to C. nivariensis were submitted to the United Kingdom Mycology Reference Laboratory for identification. The strains originated from various clinical specimens, including deep, usually sterile sites, from patients at 12 different hospitals in the United Kingdom. PCR amplification and sequencing of the D1D2 and internal transcribed spacer 1 (ITS1) regions of the nuclear ribosomal gene cassette confirmed that these isolates from the United Kingdom are genetically identical to C. nivariensis. Biochemically, C. glabrata and C. nivariensis are distinguished by their differential abilities to assimilate trehalose. However, in contrast to the original published findings, we found that C. glabrata isolates, but not C. nivariensis isolates, are capable of assimilating this substrate. Antifungal susceptibility tests revealed that C. nivariensis isolates are less susceptible than C. glabrata isolates to itraconazole, fluconazole, and voriconazole and to have significantly higher flucytosine MICs than C. glabrata strains. Finally, C. nivariensis could be rapidly distinguished from the other common pathogenic fungus species by pyrosequencing of the ITS2 region. In the light of these data, we believe that C. nivariensis should be regarded as a clinically important emerging pathogenic fungus.
Borman
Andrew M
AM
Mycology Reference Laboratory, HPA South-West Regional Laboratory, Myrtle Road, Bristol BS2 8EL, United Kingdom. Andy.Borman@ubht.nhs.uk
Petch
Rebecca
R
Linton
Christopher J
CJ
Palmer
Michael D
MD
Bridge
Paul D
PD
Johnson
Elizabeth M
EM
D000935:Antifungal Agents / Q000494:pharmacology*; D001393:Azoles / Q000494:pharmacology*; D001483:Base Sequence; D002175:Candida / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D002177:Candidiasis / Q000453:epidemiology / Q000382:microbiology; D021821:Communicable Diseases, Emerging / Q000453:epidemiology / Q000382:microbiology; D021903:DNA, Ribosomal Spacer / Q000032:analysis / Q000235:genetics; D026141:Drug Resistance, Multiple, Fungal; D006801:Humans; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D016533:Mycological Typing Techniques; D017422:Sequence Analysis, DNA / Q000379:methods; D006113:United Kingdom / Q000453:epidemiology
D000935:Antifungal Agents; D001393:Azoles; D021903:DNA, Ribosomal Spacer