Genetic Structure of Typical and Atypical Populations of Candida albicans from Africa

Forche, Anja; Schönian, Gabriele; Gräser, Yvonne; Vilgalys, Rytas; Mitchell, Thomas G.

doi:10.1006/fgbi.1999.1164

Cited by 80 publications

(72 citation statements)

References 40 publications

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“…Similarly, Candida africana was initially described as an atypical, chlamydospore-negative variant of C. albicans (17,18) but was proposed as a new species on the basis of morphological, biochemical, and physiological differences (18,19). While subsequent molecular analyses supported a varietal distinction (C. albicans var.…”

Section: T He Incidence Of Invasive Fungal Infections Caused By Unusualmentioning

confidence: 99%

Epidemiology, Antifungal Susceptibility, and Pathogenicity of Candida africana Isolates from the United Kingdom

Borman¹,

Székely²,

Linton³

et al. 2013

J Clin Microbiol

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Candida africana was previously proposed as a new species within the Candida albicans species complex, together with C. albicans and C. dubliniensis, although further phylogenetic analyses better support its status as an unusual variant within C. albicans. Here we show that C. africana can be distinguished from C. albicans and C. dubliniensis by pyrosequencing of a short region of ITS2, and we have evaluated its occurrence in clinical samples by pyrosequencing all presumptive isolates of C. albicans submitted to the Mycology Reference Laboratory over a 9-month period. The C. albicans complex constituted 826/1,839 (44.9%) of yeast isolates received over the study period and included 783 isolates of C. albicans, 28 isolates of C. dubliniensis, and 15 isolates of C. africana. In agreement with previous reports, C. africana was isolated exclusively from genital specimens, in women in the 18-to-35-year age group. Indeed, C. africana constituted 15/251 (6%) of "C. albicans" isolates from female genital specimens during the study period. C. africana isolates were germ tube positive, grew significantly more slowly than C. albicans and C. dubliniensis on conventional mycological media, could be distinguished from the other members of the C. albicans complex by appearance on chromogenic agar, and were incapable of forming chlamydospores. Here we present the detailed evaluation of epidemiological, phenotypic, and clinical features and antifungal susceptibility profiles of United Kingdom isolates of C. africana. Furthermore, we demonstrate that C. africana is significantly less pathogenic than C. albicans and C. dubliniensis in the Galleria mellonella insect systemic infection model.

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Section: T He Incidence Of Invasive Fungal Infections Caused By Unusualmentioning

confidence: 99%

Epidemiology, Antifungal Susceptibility, and Pathogenicity of Candida africana Isolates from the United Kingdom

Borman¹,

Székely²,

Linton³

et al. 2013

J Clin Microbiol

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“…For example, the basidiomycete Schizophyllum commune, originally thought to be one cosmopolitan species (Raper et al 1958), is in fact made up of three species, each with a unique geographic distribution (James et al 1999). Other examples of cryptic species with distinct ranges include the ascomycetes Histoplasma capsulatum (Kasuga et al 2003), Coccidioides immitis (Koufopanou et al 1997;Fisher et al 2001), Candida albicans, (Forche et al 1999;Schonian et al 2000), Sclerotinia sclerotiorum (Carbone and Kohn 2001a,b), and Neurospora spp. (Dettman et al 2003a,b).…”

Section: Biogeographymentioning

confidence: 99%

“…For example, in the human pathogenic fungus Candida albicans, populations from France (Pujol et al 1993), North Carolina (Gräser et al 1996), Angola and Madagascar (Forche et al 1999;Schonian et al 2000) provide evidence for both clonality and recombination. In addition, mating typelike loci are found (Hull and Johnson 1999), and C. albicans has been experimentally mated both inside a mammalian host (Hull et al 2000) and in vitro (Magee and Magee 2000).…”

Section: Sexualitymentioning

confidence: 99%

“…Neither has any correlation between genotype and geography been found in another, study using a different collection of A. fumigatus individuals and different genetic markers (Rydholm et al 2003). All other fungi postulated to have global, hemispherical, or even continental populations have proved to have more narrowly endemic populations when population genetic data were collected (e.g., Koufopanou et al 1997;Geiser et al 1998a;Forche et al 1999;James et al 1999;Schonian et al 2000;Carbone and Kohn 2001a,b;Fisher et al 2001;Kasuga et al 2003;TranDinh 2003). Studies of animal species with large geographic ranges have also elucidated endemic populations.…”

Section: Biogeographymentioning

confidence: 99%

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Cryptic Speciation in the Cosmopolitan and Clonal Human Pathogenic Fungus Aspergillus Fumigatus

et al. 2005

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Abstract. Microbes and other organisms smaller than one to a few millimeters in size are hypothesized to have global populations, in contrast to the geographically restricted ranges of larger organisms. However, fungi, which routinely have reproductive propagules no larger than 10 micrometers, challenge the generality of this hypothesis because recent studies have shown that globally distributed morphological species embrace two or more geographically restricted phylogenetic species. We used the concordance of gene genealogies to recognize phylogenetic species in the globally distributed opportunistic human pathogenic fungus, Aspergillus fumigatus. Based on DNA sequence data of five loci for each of 63 individuals collected from five continents, we have delineated two phylogenetic species in this single morphological species. Unlike all other fungi examined to date, both genetically isolated groups showed a global distribution with no evidence of a correlation between genotype and geographic location. Sexual reproduction has never been observed in A. fumigatus, but when the same data were used to explore the association of alleles at the five loci for one of the phylogenetic species, evidence was found to support recombination. The discovery of a cryptic species is medically relevant because different species are likely to differ in virulence or drug resistance. The discovery of a globally distributed A. fumigatus species clade highlights the need for ecological studies of the fungus to either document global dispersal or propose alternative mechanisms by which it persists as single, global phylogenetic population.

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“…The complete genome sequence revealed high levels of heterozygosity ($4%) across the 16-Mb diploid genome ( Jones et al 2004;van het Hoog et al 2007), and population-level variation has been demonstrated in clinical populations from different continents, regions, hospitals, and families (Forche et al 1999;Pujol et al 2002;Bougnoux et al 2006). However, the genome and population processes underlying observed variation in host populations is not well understood.…”

mentioning

confidence: 99%

Evolution inCandida albicansPopulations During a Single Passage Through a Mouse Host

et al. 2009

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The mechanisms and rates by which genotypic and phenotypic variation is generated in opportunistic, eukaryotic pathogens during growth in hosts are not well understood. We evaluated genomewide genetic and phenotypic evolution in Candida albicans, an opportunistic fungal pathogen of humans, during passage through a mouse host (in vivo) and during propagation in liquid culture (in vitro). We found slower population growth and higher rates of chromosome-level genetic variation in populations passaged in vivo relative to those grown in vitro. Interestingly, the distribution of long-range loss of heterozygosity (LOH) and chromosome rearrangement events across the genome differed for the two growth environments, while rates of short-range LOH were comparable for in vivo and in vitro populations. Further, for the in vivo populations, there was a positive correlation of cells demonstrating genetic alterations and variation in colony growth and morphology. For in vitro populations, no variation in growth phenotypes was detected. Together, our results demonstrate that passage through a living host leads to slower growth and higher rates of genomic and phenotypic variation compared to in vitro populations. Results suggest that the dynamics of population growth and genomewide rearrangement contribute to the maintenance of a commensal and opportunistic life history of C. albicans.

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Genetic Structure of Typical and Atypical Populations of Candida albicans from Africa

Cited by 80 publications

References 40 publications

Epidemiology, Antifungal Susceptibility, and Pathogenicity of Candida africana Isolates from the United Kingdom

Epidemiology, Antifungal Susceptibility, and Pathogenicity of Candida africana Isolates from the United Kingdom

Cryptic Speciation in the Cosmopolitan and Clonal Human Pathogenic Fungus Aspergillus Fumigatus

Evolution inCandida albicansPopulations During a Single Passage Through a Mouse Host

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