Population structure and properties of Candida albicans, as determined by multilocus sequence typing.
We submitted a panel of 416 isolates of Candida albicans from separate sources to multilocus sequence typing (MLST). The data generated determined a population structure in which four major clades of closely related isolates were delineated, together with eight minor clades comprising five or more isolates. By Fisher's exact test, a statistically significant association was found between particular clades and the anatomical source, geographical source, ABC genotype, decade of isolation, and homozygosity versus heterozygosity at the mating type-like locus (MTL) of the isolates in the clade. However, these associations may have been influenced by confounding variables, since in a univariate analysis of variance, only the clade associations with ABC type and anatomical source emerged as statistically significant, providing the first indication of possible differences between C. albicans strain type clades and their propensity to infect or colonize different anatomical locations. There were no significant differences between clades with respect to distributions of isolates resistant to fluconazole, itraconazole, or flucytosine. However, the majority of flucytosine-resistant isolates belonged to clade 1, and these isolates, but not flucytosine-resistant isolates in other clades, bore a unique mutation in the FUR1 gene that probably accounts for their resistance. A significantly higher proportion of isolates resistant to fluconazole, itraconazole, and flucytosine were homozygous at the MTL, suggesting that antifungal pressure may trigger a common mechanism that leads both to resistance and to MTL homozygosity. The utility of MLST for determining clade assignments of clinical isolates will form the basis for strain selection for future research into C. albicans virulence.
Tavanti
Arianna
A
Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, United Kingdom.
Davidson
Amanda D
AD
Fordyce
Mark J
MJ
Gow
Neil A R
NA
Maiden
Martin C J
MC
Odds
Frank C
FC
D000704:Analysis of Variance; D000935:Antifungal Agents / Q000494:pharmacology; D001769:Blood / Q000382:microbiology; D002176:Candida albicans / Q000145:classification* / Q000187:drug effects / Q000235:genetics; D002177:Candidiasis / Q000382:microbiology*; D025141:Drug Resistance, Fungal / Q000235:genetics; D005060:Europe; D005260:Female; D005800:Genes, Fungal / Q000235:genetics; D006801:Humans; D016533:Mycological Typing Techniques; D009656:North America; D009960:Oropharynx / Q000382:microbiology; D010802:Phylogeny; D017421:Sequence Analysis; D013045:Species Specificity; D014621:Vagina / Q000382:microbiology
D000935:Antifungal Agents