Molecular epidemiology reveals genetic diversity amongst isolates of the Cryptococcus neoformans/C. gattii species complex in Thailand

PLoS Negl Trop Dis. 2013 Jul 4;7(7):e2297. doi: 10.1371/journal.pntd.0002297. Print 2013.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Animals
  • Cluster Analysis
  • Cryptococcosis / epidemiology*
  • Cryptococcosis / microbiology
  • Cryptococcosis / veterinary*
  • Cryptococcus gattii / classification*
  • Cryptococcus gattii / genetics
  • Cryptococcus gattii / isolation & purification
  • Cryptococcus neoformans / classification*
  • Cryptococcus neoformans / genetics
  • Cryptococcus neoformans / isolation & purification
  • DNA, Fungal / chemistry
  • DNA, Fungal / genetics
  • Environmental Microbiology*
  • Female
  • Genetic Variation*
  • Genotype
  • HIV Infections / complications
  • Humans
  • Male
  • Molecular Epidemiology
  • Molecular Sequence Data
  • Molecular Typing
  • Mycological Typing Techniques
  • Polymorphism, Restriction Fragment Length
  • Retrospective Studies
  • Sequence Analysis, DNA
  • Thailand / epidemiology

Substances

  • DNA, Fungal

Associated data

  • GENBANK/KC292381
  • GENBANK/KC292382
  • GENBANK/KC292383
  • GENBANK/KC292384
  • GENBANK/KC292385
  • GENBANK/KC292386
  • GENBANK/KC292387
  • GENBANK/KC292388
  • GENBANK/KC292389
  • GENBANK/KC292390
  • GENBANK/KC292391
  • GENBANK/KC292392
  • GENBANK/KC292393
  • GENBANK/KC292394
  • GENBANK/KC292395
  • GENBANK/KC292396
  • GENBANK/KC292397
  • GENBANK/KC292398
  • GENBANK/KC292399
  • GENBANK/KC292400
  • GENBANK/KC292401
  • GENBANK/KC292402
  • GENBANK/KC292403
  • GENBANK/KC292404
  • GENBANK/KC292405
  • GENBANK/KC292406
  • GENBANK/KC292407
  • GENBANK/KC292408
  • GENBANK/KC292409
  • GENBANK/KC292410
  • GENBANK/KC292411
  • GENBANK/KC292412
  • GENBANK/KC292413
  • GENBANK/KC292414
  • GENBANK/KC292415
  • GENBANK/KC292416
  • GENBANK/KC292417
  • GENBANK/KC292418
  • GENBANK/KC292419
  • GENBANK/KC292420
  • GENBANK/KC306863

Grant support

S. Kaocharoen was supported by Chulalongkorn University Graduate Scholarship to commemorate the 72nd Anniversary of His Majesty King Bhumibol Adulyadej. This work was also supported by the 90th Anniversary of Chulalongkorn University Fund (Ratchadaphiseksomphot Endowment Fund) #2/2551 to A. Chindamporn and S. Kaocharoen, a New Researcher Scholarship of CSTS, NSTDA Ministry of Science and Technology, to P. Ngamskulrungroj and an NH&MRC project grants #352303 and APP1031943 to W. Meyer. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.