title: Identification of novel hybrids between Cryptococcus neoformans var. grubii VNI and Cryptococcus gattii VGII.
abstract: Cryptococcus neoformans and Cryptococcus gattii are pathogenic yeasts causing meningoencephalitis in immunocompromised and immunocompetent hosts. The fungus is typically haploid, and sexual reproduction occurs normally between individuals with opposite mating types, α and a. C. neoformans var. grubii (serotype A) is comprised of molecular types VNI, VNII, and VNB, and C. neoformans var. neoformans (serotype D) contains the molecular type VNIV. Additionally, diploid or aneuploid AD hybrids (VNIII) have been reported. C. gattii contains the molecular types VGI, VGII, VGIII, and VGIV, which encompass both serotypes B and C. To identify possible hybrid strains, URA5-RFLP analysis was performed on 350 globally obtained clinical, environmental, and veterinary isolates. Four clinical isolates from cerebrospinal fluid showed combination patterns of C. neoformans var. grubii and C. gattii: Brazil (n = 2), Colombia (n = 1), and India (n = 1). These strains were monokaryotic and diploid or aneuploid. M13 PCR fingerprinting showed that they contained fragments of both proposed parental groups. Luminex IGS genotyping identified these isolates as hybrids with two different molecular type combinations: three VNI/VGII and one VNI/VGI. Blue color development on CGB agar was delayed in three isolates and absent in one. C. gattii-specific PCR confirmed the presence of C. gattii in the hybrids. CAP59 allele-specific PCR revealed that all the hybrids contained both serotype A and B alleles. Determination of mating-type allelic patterns by PCR revealed that the isolates were αA aB. This is the first study discovering novel natural hybrids between C. neoformans molecular type VNI and C. gattii molecular type VGII.
authors.affiliation: Molecular Mycology Research Laboratory, Westmead, Australia.
authors.forename: Mojgan
authors.initials: M
authors.lastname: Aminnejad
authors.forename: Mara
authors.initials: M
authors.lastname: Diaz
authors.forename: Michael
authors.initials: M
authors.lastname: Arabatzis
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Castañeda
authors.forename: Marcia
authors.initials: M
authors.lastname: Lazera
authors.forename: Aristea
authors.initials: A
authors.lastname: Velegraki
authors.forename: Deborah
authors.initials: D
authors.lastname: Marriott
authors.forename: Tania C
authors.initials: TC
authors.lastname: Sorrell
authors.forename: Wieland
authors.initials: W
authors.lastname: Meyer
mesh_terms: D000818:Animals; D001938:Brazil; D003105:Colombia; D003453:Cryptococcosis / Q000382:microbiology / Q000662:veterinary; D056285:Cryptococcus gattii / Q000235:genetics* / Q000302:isolation & purification; D003455:Cryptococcus neoformans / Q000235:genetics* / Q000302:isolation & purification; D004271:DNA, Fungal / Q000235:genetics; D004783:Environmental Microbiology; D049770:Genes, Mating Type, Fungal; D005838:Genotype; D006801:Humans; D007194:India; D059785:Karyotype; D058889:Molecular Typing; D016533:Mycological Typing Techniques; D016133:Polymerase Chain Reaction; D011995:Recombination, Genetic
chemical_list: D004271:DNA, Fungal
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