Abstract Detail

Mycological Section

McDonald, Tami [1], Mukaremera, Liliane [2], Nielsen, Kirsten [2].

Analysis of the population structure and virulence of clinically isolated strains of Cryptococcus from localities in sub-Saharan Africa.

Meningitis caused by the fungus Cryptococcus neoformans is a major cause of mortality of patients with HIV/AIDS in sub-Saharan Africa. In this study, clinically isolated strains of C. neoformans including 562 isolates from Kampala, Uganda, 22 isolates from Mbarara, Uganda and 76 isolates from Cape Town, South Africa were genotyped at eight standard loci. Thirty-eight genotypes of Cryptococcus neoformans var. grubii (serotype A, both VNI and VNII), six hybrids between C. neoformans var. grubii and C. neoformans var. neoformans (A/D hybrids) and one C. gattii strain were recovered. Population structures differed between Uganda and South Africa. The population in Uganda is composed of one major clonal genotype, which is highly virulent, and several minor genotypes, including singleton genotypes and minor clonal clusters. The population in South Africa has more genotypes, including both minor clonal clusters and singleton genotypes, but no major clonal clusters. Multiple isolates of the genotypes from clonal clusters were used in a mouse model of cryptococcosis. There are differences in survival between groups of mice inoculated with different strains of C. neoformans. Analysis of cytokines in the lungs, brain and spleen of mice indicate that the mouse immune response to C. neoformans differs between strains of C. neoformans. Ultimately the genotype and mortality data can be used to select fungal strains for whole-genome sequencing to identify novel virulence factors that differ between high-mortality and low-mortality fungal genotypes.

1 - St. Catherine University, Biology, 2004 Randolph Ave, St. Paul, Minnesota, 55105, United States
2 - University of Minnesota, Department of Microbiology, 420 Delaware St. SE, Minneapolis, Minnesota, 55455, United States

Keywords:
Cryptococcus neoformans
Cryptococcus gatii
pathogenesis
virulence
mice
population
Uganda
South Africa
population structure
meningitis.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Hall D/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 5:30 PM
Number: PMY035
Abstract ID:676
Candidate for Awards:None