C. haemulonii complex: a human multi-resistant pathogenic yeast with a high genetic biodiversity

Ref ID: 17732

Author:

E. Cendejas-Bueno*, B. Theelen, A. Gómez-López, M. Cuenca-Estrella,
T. Boekhout

Author address:

Majadahonda, ES; Utrecht, NL)

Full conference title:

22nd European Congress of Clinical Microbiology and Infectious Diseases

Abstract:

Background: C. haemulonii is one of the rarest yeast species that can
be isolated from human clinical sources. Fungal infections due to this
yeast have been described in the literature, varying from superficial to
deep infections. Cases of catheter related fungemia, blood stream
infection, osteitis and outbreaks in intensive care units have been
reported recently.
The susceptibility profile of this C. haemulonii shows that is resistant to
Amphotericin B (AMB) and Fluconazole (FLC) with high Minimal
Inhibitory Concentrations (MIC) for both compounds, which can hinder
the management of patients with deep infections caused by this yeast.
This antifungal profile has often been associated with clinical failure.
Materials and methods: Thirty strains of the C. haemulonii complex
belonging to the Mycology Department of the National Centre for
Microbiology (CNM, Majadahonda, Spain) and the CBS Fungal
Biodiversity Centre (CBS-KNAW, Utrecht, The Netherlands)
collections were analyzed. The amplification and sequencing of the
ITS domain (ribosomal DNA), D1/D2 region and DNA Polimerase II
gen (RPB2) were done.
Results: From the 30 isolates of the C. haemulonii complex used in the
present study, 19 were assigned to the most commonly encountered
group (C. haemulonii group I), seven isolates were assigned to C.
haemulonii group II, and the other four Isolates were assigned to a new
cluster. Based on the ITS sequences analysis, three main clusters were
distinguished. The first one included 23 strains, four out of these 23
formed a subcluster of ’’atypical’’ strains which were positive distantly
from the other 19 C. haemulonii group I isolates. The third cluster
included strains that belong to the C. haemulonii group II. On the other
hand, the analysis of the RPB2 gene showed the same results as the
ones showed in the ITS analysis. Whereas the analysis of the D1-D2
26S rRNA gene fragment sequences only showed two different clusters.
The group formed by the four ’’atypical isolates’’ was included in the
same cluster as those of C. haemulonii.
Conclusions: (i) the molecular data of the RPB2, D1/D2 and ITS
regions demonstrate that the C. haemulonii complex has a high
genetic diversity. These data suggest that C. haemulonii complex is
composed by three different clusters. (ii) Due to the resistant
antifungal profile, more studies would be needed in order to
establish a relationship between the susceptibility profile and each
one of these three clusters.

Abstract Number: NULL

Conference Year: 2012

Link to conference website: NULL

New link: NULL

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