Analyses of pediatric isolates of Cryptococcus neoformans from South Africa.
Abstract
Compared to the incidence in adults, cryptococcosis is inexplicably rare among children,
even in sub-Saharan Africa, which has the highest prevalence of coinfection with HIV
and Cryptococcus neoformans. To explore any mycological basis for this age-related
difference in the incidence of cryptococcosis, we investigated isolates of C. neoformans
recovered from pediatric and adult patients during a 2-year period in South Africa.
From reports to the Group for Enteric, Respiratory, and Meningeal Disease Surveillance
in South Africa (GERMS-SA), we reviewed all cases of cryptococcosis in 2005 and 2006.
We analyzed one isolate of C. neoformans from each of 82 pediatric patients (<15 years
of age) and determined the multilocus sequence type (ST), mating type, ploidy, and
allelic profile. This sample included isolates of all three molecular types of serotype
A or C. neoformans var. grubii (molecular types VNI, VNII, and VNB) and one AD hybrid.
Seventy-seven (94%) of the strains possessed the MATα mating type allele, and five
were MATa. Seventy-five (91%) were haploid, and seven were diploid. A total of 24
different STs were identified. The ratios of each mating type and the proportion of
haploids were comparable to those for the isolates that were obtained from 86 adult
patients during the same period. Notably, the most prevalent pediatric ST was significantly
associated with male patients. Overall, these pediatric isolates exhibited high genotypic
diversity. They included a relatively large percentage of diploids and the rarely
reported MATa mating type.
Type
Journal articleSubject
AdolescentAdult
Alleles
Child
Child, Preschool
Cryptococcosis
Cryptococcus neoformans
DNA, Fungal
Female
Genes, Mating Type, Fungal
Genetic Variation
Genotype
Humans
Infant
Infant, Newborn
Male
Molecular Sequence Data
Multilocus Sequence Typing
Mycological Typing Techniques
Ploidies
Sequence Analysis, DNA
South Africa
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https://hdl.handle.net/10161/11069Published Version (Please cite this version)
10.1128/JCM.01277-10Publication Info
Miglia, Kathleen J; Govender, Nelesh P; Rossouw, Jenny; Meiring, Susan; Mitchell,
Thomas G; & Group for Enteric, Respiratory and Meningeal Disease Surveillance in South
Africa (2011). Analyses of pediatric isolates of Cryptococcus neoformans from South Africa. J Clin Microbiol, 49(1). pp. 307-314. 10.1128/JCM.01277-10. Retrieved from https://hdl.handle.net/10161/11069.This is constructed from limited available data and may be imprecise. To cite this
article, please review & use the official citation provided by the journal.
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Thomas Greenfield Mitchell
Associate Professor Emeritus in Molecular Genetics and Microbiology
Among patients with AIDS, leukemia or other cancers, organ or bone marrow transplants,
and similar immunocompromising risk factors, the incidence of opportunistic mycoses
and the number of different fungal pathogens are increasing dramatically. For many
of these fungi, the definition of a species and the recognition of pathogen are highly
problematic. Conventional methods of identification are based on morphological and
physiological characteristics and are often time-consuming, difficult to int

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