Genotypic analysis of clinical and environmental Cryptococcus neoformans isolates from Brazil reveals the presence of VNB isolates and a correlation with biological factors

PLoS One. 2018 Mar 5;13(3):e0193237. doi: 10.1371/journal.pone.0193237. eCollection 2018.

Abstract

Cryptococcal infections are mainly caused by members of the Cryptococcus neoformans species complex (molecular types VNI, VNII, VNB, VNIV and the AD hybrid VNIII). PCR of the mating type loci and MLST typing using the ISHAM-MLST consensus scheme were used to evaluate the genetic relationship of 102 (63 clinical and 39 environmental) C. neoformans isolates from Uberaba, Brazil and to correlate the obtained genotypes with clinical, antifungal susceptibility and virulence factor data. All isolates were mating type alpha. MLST identified 12 known and five new sequence types (ST). Fourteen STs were identified within the VNI isolates, with ST93 (57/102, 56%) and ST77 (19/102, 19%) being the most prevalent. From the nine VNII isolates previously identify by URA5-RFLP only four (ST40) were confirmed by MLST. The remaining five grouped within the VNB clade in the phylogenetic analysis corresponding to the sequence type ST504. Other two environmental isolates also grouped within VNB clade with the new sequence type ST527. The four VNII/ST40 isolates were isolated from CSF. The two VNIV sequence types (ST11 and ST160) were isolated from blood cultures. Two of six patients evaluated with more than one isolates had mixed infections. Amongst the VNI isolates 4 populations were identified, which showed differences in their susceptibility profiles, clinical outcome and virulence factors. These results reinforce that ST93 is the most prevalent ST in HIV-infected patients in the Southeastern region of Brazil. The finding of the VNB molecular type amongst environmental Brazilian isolates highlights that this genotype is not restricted to the African continent.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Antifungal Agents / pharmacology
  • Bacterial Typing Techniques
  • Brazil
  • Cryptococcus neoformans / classification
  • Cryptococcus neoformans / drug effects
  • Cryptococcus neoformans / genetics*
  • Environment*
  • Female
  • Genes, Mating Type, Fungal / genetics
  • Genetic Variation
  • Genotype*
  • Humans
  • Male
  • Multilocus Sequence Typing
  • Phenotype

Substances

  • Antifungal Agents

Grants and funding

This work was supported by Grant Support Foundation of Minas Gerais (FAPEMIG) - Grant: #APQ71035 / 2010 to MLSV, and an NH & MRC grant #APP1031943 to WM. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.