Browsing by Author "Bicanic, Tihana"
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Item Open Access AIDS-Related Mycoses: Current Progress in the Field and Future Priorities(Trends in Microbiology, 2017-06) Armstrong-James, Darius; Bicanic, Tihana; Brown, Gordon D; Hoving, Jennifer C; Meintjes, Graeme; Nielsen, KirstenItem Open Access Leave no one behind: response to new evidence and guidelines for the management of cryptococcal meningitis in low-income and middle-income countries.(The Lancet. Infectious Diseases, 2019-04) Loyse, Angela; Burry, Jessica; Cohn, Jennifer; Ford, Nathan; Chiller, Tom; Ribeiro, Isabela; Koulla-Shiro, Sinata; Mghamba, Janneth; Ramadhani, Angela; Nyirenda, Rose; Aliyu, Sani H; Wilson, Douglas; Le, Thuy; Oladele, Rita; Lesikari, Sokoine; Muzoora, Conrad; Kalata, Newton; Temfack, Elvis; Mapoure, Yacouba; Sini, Victor; Chanda, Duncan; Shimwela, Meshack; Lakhi, Shabir; Ngoma, Jonathon; Gondwe-Chunda, Lilian; Perfect, Chase; Shroufi, Amir; Andrieux-Meyer, Isabelle; Chan, Adrienne; Schutz, Charlotte; Hosseinipour, Mina; Van der Horst, Charles; Klausner, Jeffrey D; Boulware, David R; Heyderman, Robert; Lalloo, David; Day, Jeremy; Jarvis, Joseph N; Rodrigues, Marcio; Jaffar, Shabbar; Denning, David; Migone, Chantal; Doherty, Megan; Lortholary, Olivier; Dromer, Françoise; Stack, Muirgen; Molloy, Síle F; Bicanic, Tihana; van Oosterhout, Joep; Mwaba, Peter; Kanyama, Cecilia; Kouanfack, Charles; Mfinanga, Sayoki; Govender, Nelesh; Harrison, Thomas SIn 2018, WHO issued guidelines for the diagnosis, prevention, and management of HIV-related cryptococcal disease. Two strategies are recommended to reduce the high mortality associated with HIV-related cryptococcal meningitis in low-income and middle-income countries (LMICs): optimised combination therapies for confirmed meningitis cases and cryptococcal antigen screening programmes for ambulatory people living with HIV who access care. WHO's preferred therapy for the treatment of HIV-related cryptococcal meningitis in LMICs is 1 week of amphotericin B plus flucytosine, and the alternative therapy is 2 weeks of fluconazole plus flucytosine. In the ACTA trial, 1-week (short course) amphotericin B plus flucytosine resulted in a 10-week mortality of 24% (95% CI -16 to 32) and 2 weeks of fluconazole and flucytosine resulted in a 10-week mortality of 35% (95% CI -29 to 41). However, with widely used fluconazole monotherapy, mortality because of HIV-related cryptococcal meningitis is approximately 70% in many African LMIC settings. Therefore, the potential to transform the management of HIV-related cryptococcal meningitis in resource-limited settings is substantial. Sustainable access to essential medicines, including flucytosine and amphotericin B, in LMICs is paramount and the focus of this Personal View.Item Open Access The Cryptococcus neoformans transcriptome at the site of human meningitis(mBio, 2014-02-04) Chen, Yuan; Toffaletti, Dena L; Tenor, Jennifer L; Litvintseva, Anastasia P; Fang, Charles; Mitchell, Thomas G; McDonald, Tami R; Nielsen, Kirsten; Boulware, David R; Bicanic, Tihana; Perfect, John RCryptococcus neoformans is the leading cause of fungal meningitis worldwide. Previous studies have characterized the cryptococcal transcriptome under various stress conditions, but a comprehensive profile of the C. neoformans transcriptome in the human host has not been attempted. Here, we extracted RNA from yeast cells taken directly from the cerebrospinal fluid (CSF) of two AIDS patients with cryptococcal meningitis prior to antifungal therapy. The patients were infected with strains of C. neoformans var. grubii of molecular type VNI and VNII. Using RNA-seq, we compared the transcriptional profiles of these strains under three environmental conditions (in vivo CSF, ex vivo CSF, and yeast extract-peptone-dextrose [YPD]). Although we identified a number of differentially expressed genes, single nucleotide variants, and novel genes that were unique to each strain, the overall expression patterns of the two strains were similar under the same environmental conditions. Specifically, yeast cells obtained directly from each patient's CSF were more metabolically active than cells that were incubated ex vivo in CSF. Compared with growth in YPD, some genes were identified as significantly upregulated in both in vivo and ex vivo CSF, and they were associated with genes previously recognized for contributing to pathogenicity. For example, genes with known stress response functions, such as RIM101, ENA1, and CFO1, were regulated similarly in the two clinical strains. Conversely, many genes that were differentially regulated between the two strains appeared to be transporters. These findings establish a platform for further studies of how this yeast survives and produces disease. © 2014 Chen et al.Item Open Access Variation in chromosome copy number influences the virulence of Cryptococcus neoformans and occurs in isolates from AIDS patients.(BMC Genomics, 2011-10-27) Hu, Guanggan; Wang, Joyce; Choi, Jaehyuk; Jung, Won Hee; Liu, Iris; Litvintseva, Anastasia P; Bicanic, Tihana; Aurora, Rajeev; Mitchell, Thomas G; Perfect, John R; Kronstad, James WBACKGROUND: The adaptation of pathogenic fungi to the host environment via large-scale genomic changes is a poorly characterized phenomenon. Cryptococcus neoformans is the leading cause of fungal meningoencephalitis in HIV/AIDS patients, and we recently discovered clinical strains of the fungus that are disomic for chromosome 13. Here, we examined the genome plasticity and phenotypes of monosomic and disomic strains, and compared their virulence in a mouse model of cryptococcosis RESULTS: In an initial set of strains, melanin production was correlated with monosomy at chromosome 13, and disomic variants were less melanized and attenuated for virulence in mice. After growth in culture or passage through mice, subsequent strains were identified that varied in melanin formation and exhibited copy number changes for other chromosomes. The correlation between melanin and disomy at chromosome 13 was observed for some but not all strains. A survey of environmental and clinical isolates maintained in culture revealed few occurrences of disomic chromosomes. However, an examination of isolates that were freshly collected from the cerebrospinal fluid of AIDS patients and minimally cultured provided evidence for infections with multiple strains and copy number variation. CONCLUSIONS: Overall, these results suggest that the genome of C. neoformans exhibits a greater degree of plasticity than previously appreciated. Furthermore, the expression of an essential virulence factor and the severity of disease are associated with genome variation. The occurrence of chromosomal variation in isolates from AIDS patients, combined with the observed influence of disomy on virulence, indicates that genome plasticity may have clinical relevance.