Comparative Gene Genealogies Indicate that Two Clonal Lineages ofCryptococcus gattiiin British Columbia ResembleStrains from Other Geographical Areas

Abstract

Cryptococcus gattii has recently emerged as a pathogen of humans and animals in the temperate climate of Vancouver Island, British Columbia (B.C.). The majority (ϳ95%) of the isolates from the island belong to the VGII molecular type, and the remainder belong to the VGI molecular type. The goals of this study were to compare patterns of molecular variation among C. gattii isolates from B.C. with those from different areas of the world and to investigate the population structure using a comparative gene genealogy approach. Our results indicate that the C. gattii population in B.C. comprises at least two divergent lineages, corresponding to previously identified VGI and VGII molecular types. The genealogical analysis of strains suggested a predominantly clonal population structure among B.C. isolates, while there was evidence for sexual recombination between different molecular types on a global scale. We found no geographic pattern of strain relationships, and nucleotide sequence comparisons revealed that genotypes among isolates from B.C. were also present among isolates from other areas of the world, indicating extensive strain dispersal. The nucleotide sequence diversity among isolates from B.C. was similar to that among isolates from other areas of the world.

The fatal fungal outbreak on Vancouver Island is characterized by enhanced intracellular parasitism driven by mitochondrial regulation

“…Previous amplified fragment length polymorphism (AFLP) and multilocus sequence typing (MLST) studies have demonstrated that the Vancouver Island outbreak (VIO) is mainly caused by a single, hypervirulent genotype of C. gattii (AFLP6A/molecular type VGIIa) (8). Intriguingly, this genotype is not restricted to Vancouver Island but is also shared by, for instance, the CBS6956 strain (also known as NIH444 or ATCC32609, isolated from a patient in Seattle in 1971) and CBS7750 (isolated from a Eucalyptus tree in San Francisco in 1992) (11,12), suggesting that a recent genetic change has occurred within the VIO lineage, potentially as a result of an unusual same-sex mating event (12). However, the underlying molecular cause for the hypervirulence of this lineage remains unknown.…”

First Contemporary Case of Human Infection with Cryptococcus gattii in Puget Sound: Evidence for Spread of the Vancouver Island Outbreak

“…Genotypic analysis revealed that virtually all environmental and clinical isolates belong to the VGII genotype of C. gattii (7). Studies using PCR fingerprinting, restriction fragment length polymorphism (RFLP) analysis, and amplified fragment length polymorphism (AFLP) analysis (7) identified two distinct genotypes among the isolates from Vancouver Island (VGIIa/AFLP6a and VGIIb/AFLP6B), which were later supported by multilocus sequence typing (MLST) (4,6). Given the close proximity, climatic and geographic similarities to Vancouver Island, and potential clinical importance, we have sought to determine whether this pathogenic microbe has spread to the Puget Sound area in the United States.…”

Correlation of Genotype and In Vitro Susceptibilities of Cryptococcus gattii Strains from the Pacific Northwest of the United States

“…The majority of cases in this outbreak were caused by C. gattii of the clonal subtype VGIIa, with a minority of isolates caused by the clonal subtype VGIIb (12,17,18), but other subtypes have also been isolated during this ongoing outbreak (17).…”