Genotypic and Phenotypic Diversity of Cryptococcus gattii VGII Clinical Isolates and Its Impact on Virulence

Barcellos, Vanessa Abreu; Martins, Liline Maria Soares; Fontes, Alide Caroline Lima; Reuwsaat, Júlia Catarina Vieira; Squizani, Eamim Daidrê; Araújo, Glaucy Rodrigues de; Frasés, Susana; Staats, Charley Christian; Schrank, Augusto; Kmetzsch, Lívia; Vainstein, Marilene Henning

doi:10.3389/fmicb.2018.00132

Cited by 17 publications

(17 citation statements)

References 70 publications

(103 reference statements)

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“…Our current study showed that C. gattii species complex infection in Guangxi, southern China were caused by both C. gattii s.s. (AFLP4/VGI) and C. deuterogattii (AFLP6/VGII), with different MLST genotypes and virulence factor characteristics. Similar pattern has also been reported in other countries such as Canada, Brazil, Australia and the USA [29][30][31]. Although C. deuterogattii in this study was genetically indistinguishable from the outbreak genotypes AFLP6A/VGIIa (R265) and AFLP6C/VGIIc (A6M-R38), they were related to other global C. https://doi.org/10.1371/journal.pntd.0008493.g003…”

Section: Discussionsupporting

confidence: 87%

“…Since certain strains were able to mate in vitro, we also studied and compared their virulence factors to the standard reference strain (R265). Melanin production, and capsule formation were evaluated using slightly modified protocols that were published previously [29][30][31]. Visual analysis of melanin production was performed on caffeic acid agar; strains were grown on agar plates incubated at 30˚C and 37˚C for 72 h and observed the appearance of brown yeast colonies.…”

Section: Mating Type Determination and Physiological Analysismentioning

confidence: 99%

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Emerging Cryptococcus gattii species complex infections in Guangxi, southern China

et al. 2020

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The emergence and spread of cryptococcosis caused by the Cryptococcus gattii species complex has become a major public concern worldwide. C. deuterogattii (VGIIa) outbreaks in the Pacific Northwest region demonstrate the expansion of this fungal infection to temperate climate regions. However, infections due to the C. gattii species complex in China have rarely been reported. In this study, we studied eleven clinical strains of the C. gattii species complex isolated from Guangxi, southern China. The genetic identity and variability of these isolates were analyzed via multi-locus sequence typing (MLST), and the phylogenetic relationships among these isolates and global isolates were evaluated. The mating type, physiological features and antifungal susceptibilities of these isolates were also characterized. Among the eleven isolates, six belonged to C. deuterogattii, while five belonged to C. gattii sensu stricto. The C. deuterogattii strains from Guangxi, southern China were genetically variable and clustered with different clinical isolates from Brazil. All strains were MATα, and three C. deuterogattii isolates (GX0104, GX0105 and GX0147) were able to undergo sexual reproduction. Moreover, most strains had capsule and were capable of melanin production when compared to the outbreak strain from Canada. Most isolates were susceptible to antifungal drugs; yet one of eleven immunocompetent patients died of cryptococcal meningitis caused by C. deuterogattii (GX0147). Our study indicated that the highly pathogenic C. deuterogattii may be emerging in southern China, and effective nationwide surveillance of C. gattii species complex infection is necessary.

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Section: Discussionsupporting

confidence: 87%

Section: Mating Type Determination and Physiological Analysismentioning

confidence: 99%

Emerging Cryptococcus gattii species complex infections in Guangxi, southern China

et al. 2020

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“…However, the main differences between both models is the duration of the experiments, with the Galleria model cutting down the time to less than two weeks, while the mouse model takes almost two months (Figure 3). Similarly, larval tissue damage was more evident in larvae inoculated with high-virulence strains, as seen previously in murine models, in which rodents inoculated with strains of higher virulence presented a higher fungal burden [31][32][33]. Skeletal damage at the tissue level and nodular lesions consist typically of an accumulation of yeast masses that can be observed causing tissue disorganization, which resembles the formation of granulomas or lesions in the brain parenchyma in pulmonary or meningeal cryptococcosis, respectively [45].…”

Section: Discussionsupporting

confidence: 67%

“…In addition, apart from studying the pathophysiology of different fungal species, more recently, this invertebrate model has been successfully used for testing the in vivo efficacy of conventional and novel antifungal drugs [27]. In the case of Cryptococcus neoformans and C. gattii, several approaches using mainly vertebrate but also invertebrate models have been used to study fungal pathogenicity [10,[28][29][30][31][32][33], recognize genes involved in pathogenicity, identify strain virulence, virulence factors (including capsule, melanin production and biofilm formation), and undertake antifungal susceptibility testing of existing and new compounds [34][35][36][37][38][39].…”

Section: Discussionmentioning

confidence: 99%

Rearing and Maintenance of Galleria mellonella and Its Application to Study Fungal Virulence

Firacative

Khan

Duan

et al. 2020

JoF

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Galleria mellonella larvae have been widely used as alternative non-mammalian models for the study of fungal virulence and pathogenesis. The larvae can be acquired in small volumes from worm farms, pet stores, or other independent suppliers commonly found in the United States and parts of Europe. However, in countries with no or limited commercial availability, the process of shipping these larvae can cause them stress, resulting in decreased or altered immunity. Furthermore, the conditions used to rear these larvae including diet, humidity, temperature, and maintenance procedures vary among the suppliers. Variation in these factors can affect the response of G. mellonella larvae to infection, thereby decreasing the reproducibility of fungal virulence experiments. There is a critical need for standardized procedures and incubation conditions for rearing G. mellonella to produce quality, unstressed larvae with the least genetic variability. In order to standardize these procedures, cost-effective protocols for the propagation and maintenance of G. mellonella larvae using an artificial diet, which has been successfully used in our own laboratory, requiring minimal equipment and expertise, are herein described. Examples for the application of this model in fungal pathogenicity and gene knockout studies as feasible alternatives for traditionally used animal models are also provided.

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“…There is considerable variation in virulence-associated traits and antifungal drug resistance both within and between Cryptococcus species (Barchiesi et al, 2005;Litvintseva and Mitchell, 2009;Mukaremera et al, 2019;Martinez et al, 2001;Sun et al, 2014;Small and Mitchell, 1989;Barcellos et al, 2018;Samarasinghe et al, 2018;Hagen et al, 2016;Matos et al, 2018). One of the most powerful approaches for dissecting the genetic basis of phenotypic variation is quantitative trait locus (QTL) mapping (Lander and Botstein, 1989;Lynch and Walsh, 1998).…”

Section: Introductionmentioning

confidence: 99%

Pleiotropy and epistasis within and between signaling pathways defines the genetic architecture of fungal virulence

Roth

Murray

Scott

et al. 2020

Preprint

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Cryptococcal disease is estimated to affect nearly a quarter of a million people annually. Environmental isolates of Cryptococcus deneoformans, which make up 15 to 30% of clinical infections in temperate climates such as Europe, vary in their pathogenicity, ranging from benign to hyper-virulent. Key traits that contribute to virulence, such as the production of the pigment melanin, an extracellular polysaccharide capsule, and the ability to grow at human body temperature have been identified, yet little is known about the genetic basis of variation in such traits. Here we investigate the genetic basis of melanization, capsule size, thermal tolerance, oxidative stress resistance, and antifungal drug sensitivity using quantitative trait locus (QTL) mapping in progeny derived from a cross between two divergent C. deneoformans strains. Using a "function-valued" QTL analysis framework that exploits both time-series information and growth differences across multiple environments, we identified QTL for each of these virulence traits and drug susceptibility. For three QTL we identified the underlying genes and nucleotide differences that govern variation in virulence traits. One of these genes, RIC8, which encodes a regulator of cAMP-PKA signaling, contributes to variation in four virulence traits: melanization, capsule size, thermal tolerance, and resistance to oxidative stress. Two major effect QTL for amphotericin B resistance map to the genes SSK1 and SSK2, which encode key components of the HOG pathway, a fungal-specific signal transduction network that orchestrates cellular responses to osmotic and other stresses. We also discovered complex epistatic interactions within and between genes in the HOG and cAMP-PKA pathways that regulate antifungal drug resistance and resistance to oxdiative stress. Our findings advance the understanding of virulence traits among diverse lineages of Cryptococcus, and highlight the role of genetic variation in key stress-responsive signaling pathways as a major contributor to phenotypic variation.

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Genotypic and Phenotypic Diversity of Cryptococcus gattii VGII Clinical Isolates and Its Impact on Virulence

Cited by 17 publications

References 70 publications

Emerging Cryptococcus gattii species complex infections in Guangxi, southern China

Emerging Cryptococcus gattii species complex infections in Guangxi, southern China

Rearing and Maintenance of Galleria mellonella and Its Application to Study Fungal Virulence

Pleiotropy and epistasis within and between signaling pathways defines the genetic architecture of fungal virulence

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