title: Molecular epidemiology reveals genetic diversity amongst isolates of the Cryptococcus neoformans/C. gattii species complex in Thailand.
abstract: To gain a more detailed picture of cryptococcosis in Thailand, a retrospective study of 498 C. neoformans and C. gattii isolates has been conducted. Among these, 386, 83 and 29 strains were from clinical, environmental and veterinary sources, respectively. A total of 485 C. neoformans and 13 C. gattii strains were studied. The majority of the strains (68.9%) were isolated from males (mean age of 37.97 years), 88.5% of C. neoformans and only 37.5% of C. gattii strains were from HIV patients. URA5-RFLP and/or M13 PCR-fingerprinting analysis revealed that the majority of the isolates were C. neoformans molecular type VNI regardless of their sources (94.8%; 94.6% of the clinical, 98.8% of the environmental and 86.2% of the veterinary isolates). In addition, the molecular types VNII (2.4%; 66.7% of the clinical and 33.3% of the veterinary isolates), VNIV (0.2%; 100% environmental isolate), VGI (0.2%; 100% clinical isolate) and VGII (2.4%; 100% clinical isolates) were found less frequently. Multilocus Sequence Type (MLST) analysis using the ISHAM consensus MLST scheme for the C. neoformans/C. gattii species complex identified a total of 20 sequence types (ST) in Thailand combining current and previous data. The Thai isolates are an integrated part of the global cryptococcal population genetic structure, with ST30 for C. gattii and ST82, ST83, ST137, ST141, ST172 and ST173 for C. neoformans being unique to Thailand. Most of the C. gattii isolates were ST7 = VGIIb, which is identical to the less virulent minor Vancouver island outbreak genotype, indicating Thailand as a stepping stone in the global spread of this outbreak strain. The current study revealed a greater genetic diversity and a wider range of major molecular types being present amongst Thai cryptococcal isolates than previously reported.
authors.affiliation: Mycology Laboratory, King Chulalongkorn Memorial Hospital, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Sirada
authors.initials: S
authors.lastname: Kaocharoen
authors.forename: Popchai
authors.initials: P
authors.lastname: Ngamskulrungroj
authors.forename: Carolina
authors.initials: C
authors.lastname: Firacative
authors.forename: Luciana
authors.initials: L
authors.lastname: Trilles
authors.forename: Dumrongdej
authors.initials: D
authors.lastname: Piyabongkarn
authors.forename: Wijit
authors.initials: W
authors.lastname: Banlunara
authors.forename: Natteewan
authors.initials: N
authors.lastname: Poonwan
authors.forename: Angkana
authors.initials: A
authors.lastname: Chaiprasert
authors.forename: Wieland
authors.initials: W
authors.lastname: Meyer
authors.forename: Ariya
authors.initials: A
authors.lastname: Chindamporn
mesh_terms: D000328:Adult; D000818:Animals; D016000:Cluster Analysis; D003453:Cryptococcosis / Q000453:epidemiology* / Q000382:microbiology / Q000662:veterinary*; D056285:Cryptococcus gattii / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D003455:Cryptococcus neoformans / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D004783:Environmental Microbiology; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D015658:HIV Infections / Q000150:complications; D006801:Humans; D008297:Male; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D058889:Molecular Typing; D016533:Mycological Typing Techniques; D012150:Polymorphism, Restriction Fragment Length; D012189:Retrospective Studies; D017422:Sequence Analysis, DNA; D013785:Thailand / Q000453:epidemiology
chemical_list: D004271:DNA, Fungal