Candida duobushaemulonii: An Old But Unreported Pathogen.

Irene Jurado-Martín,Elena Eraso,Esther Tamayo,Cristina Marcos-Arias,Guillermo Quindós,Piet W J De Groot,Andrea Guridi

doi:10.3390/jof6040374

Abstract

Candidiasis caused by species of the Candida haemulonii complex (Candida haemulonii and Candida duobushaemulonii) and closely related species, Candida auris and Candida pseudohaemulonii are increasing. These species often show reduced susceptibility to antifungal drugs, such as azoles and amphotericin B or, less frequently, echinocandins. However, conventional phenotypic identification methods are unable to accurately differentiate these species and, therefore, their prevalence may have been underestimated. In this study, 150 isolates that were probably misidentified were reanalyzed using two novel PCR approaches. We found that one isolate previously identified in 1996 as Candida intermedia was C. duobushaemulonii, being one of the oldest isolates of this species described to date. We also found that this isolate had reduced susceptibility to fluconazole, itraconazole, and amphotericin B.

Highlights

The genus Candida is demonstrated to be genetically heterogeneous
In the same year, as further studies revealed the heterogeneity in the DNA sequence of various genes, the complex was reclassified as two species (C. haemulonii sensu stricto and Candida duobushaemulonii) and one variety (C. haemulonii var. vulnera) [4]
As the quality control band of 5/8 C. rugosa, 7/8 C. lipolytica, 1/2 C. magnoliae, and 1/8 C. intermedia was absent, internal transcribed spacer (ITS) sequencing was performed for these isolates

Summary

Introduction

Many Candida species belong to a complex formed by various cryptic species that are phenotypically identical, and only molecular-based methods guarantee their accurate identification [1]. This is the case for Candida haemulonii, an opportunistic pathogen whose first clinical isolation, from a blood sample, was described in 1984 [2]. In the same year, as further studies revealed the heterogeneity in the DNA sequence of various genes, the complex was reclassified as two species (C. haemulonii sensu stricto and Candida duobushaemulonii) and one variety Two new species phylogenetically close to C. haemulonii complex, namely, Candida pseudohaemulonii and Candida auris, were described in 2006 and 2009, respectively [5,6]

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Conclusion