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Clonality and α-a recombination in the Australian Cryptococcus gattii VGII population--an emerging outbreak in Australia.

Carriconde F, Gilgado F, Arthur I, Ellis D, Malik R, van de Wiele N, Robert V, Currie BJ, Meyer W - PLoS ONE (2011)

Bottom Line: Despite the overall clonality observed, the presence of MATa VGII isolates in Australia was demonstrated for the first time in association with recombination in MATα-MATa populations.The detection of sexual recombination in MATα-MATa population in Australia is in accordance with the natural life cycle of C. gattii involving opposite mating types and presents an alternative to the same-sex mating strategy suggested elsewhere.The potential for an Australian wide outbreak highlights the crucial issue to develop active surveillance procedures.

View Article: PubMed Central - PubMed

Affiliation: Sydney Emerging Infections and Biosecurity Institute, The University of Sydney, Sydney, New South Wales, Australia.

ABSTRACT

Background: Cryptococcus gattii is a basidiomycetous yeast that causes life-threatening disease in humans and animals. Within C. gattii, four molecular types are recognized (VGI to VGIV). The Australian VGII population has been in the spotlight since 2005, when it was suggested as the possible origin for the ongoing outbreak at Vancouver Island (British Columbia, Canada), with same-sex mating being suggested as the driving force behind the emergence of this outbreak, and is nowadays hypothesized as a widespread phenomenon in C. gattii. However, an in-depth characterization of the Australian VGII population is still lacking. The present work aimed to define the genetic variability within the Australian VGII population and determine processes shaping its population structure.

Methodology/principal findings: A total of 54 clinical, veterinary and environmental VGII isolates from different parts of the Australian continent were studied. To place the Australian population in a global context, 17 isolates from North America, Europe, Asia and South America were included. Genetic variability was assessed using the newly adopted international consensus multi-locus sequence typing (MLST) scheme, including seven genetic loci: CAP59, GPD1, LAC1, PLB1, SOD1, URA5 and IGS1. Despite the overall clonality observed, the presence of MATa VGII isolates in Australia was demonstrated for the first time in association with recombination in MATα-MATa populations. Our results also support the hypothesis of a "smouldering" outbreak throughout the Australian continent, involving a limited number of VGII genotypes, which is possibly caused by a founder effect followed by a clonal expansion.

Conclusions/significance: The detection of sexual recombination in MATα-MATa population in Australia is in accordance with the natural life cycle of C. gattii involving opposite mating types and presents an alternative to the same-sex mating strategy suggested elsewhere. The potential for an Australian wide outbreak highlights the crucial issue to develop active surveillance procedures.

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Related in: MedlinePlus

Spatial distribution of the different sequence types delineated in the Australian C. gattii VGII population.Pie charts are proportional to the number of samples. The symbols n and nST corresponds to the number of samples and the number of sequence types observed, respectively.
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pone-0016936-g004: Spatial distribution of the different sequence types delineated in the Australian C. gattii VGII population.Pie charts are proportional to the number of samples. The symbols n and nST corresponds to the number of samples and the number of sequence types observed, respectively.

Mentions: Looking at the geographical regions within Australia, WA showed the highest genetic diversity, with five sequence types detected out of the six present throughout Australia (Figure 4). Among the five genotypes detected in this state three were so far unique to WA (ST5, ST38 and ST48) (Figure 1 and Figure 4). In the NT and NSW, two sequence types were observed, while only one was delineated in QLD.


Clonality and α-a recombination in the Australian Cryptococcus gattii VGII population--an emerging outbreak in Australia.

Carriconde F, Gilgado F, Arthur I, Ellis D, Malik R, van de Wiele N, Robert V, Currie BJ, Meyer W - PLoS ONE (2011)

Spatial distribution of the different sequence types delineated in the Australian C. gattii VGII population.Pie charts are proportional to the number of samples. The symbols n and nST corresponds to the number of samples and the number of sequence types observed, respectively.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3044715&req=5

pone-0016936-g004: Spatial distribution of the different sequence types delineated in the Australian C. gattii VGII population.Pie charts are proportional to the number of samples. The symbols n and nST corresponds to the number of samples and the number of sequence types observed, respectively.
Mentions: Looking at the geographical regions within Australia, WA showed the highest genetic diversity, with five sequence types detected out of the six present throughout Australia (Figure 4). Among the five genotypes detected in this state three were so far unique to WA (ST5, ST38 and ST48) (Figure 1 and Figure 4). In the NT and NSW, two sequence types were observed, while only one was delineated in QLD.

Bottom Line: Despite the overall clonality observed, the presence of MATa VGII isolates in Australia was demonstrated for the first time in association with recombination in MATα-MATa populations.The detection of sexual recombination in MATα-MATa population in Australia is in accordance with the natural life cycle of C. gattii involving opposite mating types and presents an alternative to the same-sex mating strategy suggested elsewhere.The potential for an Australian wide outbreak highlights the crucial issue to develop active surveillance procedures.

View Article: PubMed Central - PubMed

Affiliation: Sydney Emerging Infections and Biosecurity Institute, The University of Sydney, Sydney, New South Wales, Australia.

ABSTRACT

Background: Cryptococcus gattii is a basidiomycetous yeast that causes life-threatening disease in humans and animals. Within C. gattii, four molecular types are recognized (VGI to VGIV). The Australian VGII population has been in the spotlight since 2005, when it was suggested as the possible origin for the ongoing outbreak at Vancouver Island (British Columbia, Canada), with same-sex mating being suggested as the driving force behind the emergence of this outbreak, and is nowadays hypothesized as a widespread phenomenon in C. gattii. However, an in-depth characterization of the Australian VGII population is still lacking. The present work aimed to define the genetic variability within the Australian VGII population and determine processes shaping its population structure.

Methodology/principal findings: A total of 54 clinical, veterinary and environmental VGII isolates from different parts of the Australian continent were studied. To place the Australian population in a global context, 17 isolates from North America, Europe, Asia and South America were included. Genetic variability was assessed using the newly adopted international consensus multi-locus sequence typing (MLST) scheme, including seven genetic loci: CAP59, GPD1, LAC1, PLB1, SOD1, URA5 and IGS1. Despite the overall clonality observed, the presence of MATa VGII isolates in Australia was demonstrated for the first time in association with recombination in MATα-MATa populations. Our results also support the hypothesis of a "smouldering" outbreak throughout the Australian continent, involving a limited number of VGII genotypes, which is possibly caused by a founder effect followed by a clonal expansion.

Conclusions/significance: The detection of sexual recombination in MATα-MATa population in Australia is in accordance with the natural life cycle of C. gattii involving opposite mating types and presents an alternative to the same-sex mating strategy suggested elsewhere. The potential for an Australian wide outbreak highlights the crucial issue to develop active surveillance procedures.

Show MeSH
Related in: MedlinePlus