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Cited by 365Fungal Infections and StudiesAntifungal resistance and susceptibilityBacterial Infections and Vaccines

Treatment strategies for cryptococcal infection: challenges, advances and future outlook

Open access
Iyer, Kali R., Revie, Nicole M., Fu, Ci, Robbins, Nicole, Cowen, Leah E.·2021·Nature Reviews Microbiology
DOI 10.1038/s41579-021-00511-0PMC PMC7868659
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Abstract

Cryptococcus spp., in particular Cryptococcus neoformans and Cryptococcus gattii, have an enormous impact on human health worldwide. The global burden of cryptococcal meningitis is almost a quarter of a million cases and 181,000 deaths annually, with mortality rates of 100% if infections remain untreated. Despite these alarming statistics, treatment options for cryptococcosis remain limited, with only three major classes of drugs approved for clinical use. Exacerbating the public health burden is the fact that the only new class of antifungal drugs developed in decades, the echinocandins, displays negligible antifungal activity against Cryptococcus spp., and the efficacy of the remaining therapeutics is hampered by host toxicity and pathogen resistance. Here, we describe the current arsenal of antifungal agents and the treatment strategies employed to manage cryptococcal disease. We further elaborate on the recent advances in our understanding of the intrinsic and adaptive resistance mechanisms that are utilized by Cryptococcus spp. to evade therapeutic treatments. Finally, we review potential therapeutic strategies, including combination therapy, the targeting of virulence traits, impairing stress response pathways and modulating host immunity, to effectively treat infections caused by Cryptococcus spp. Overall, understanding of the mechanisms that regulate anti-cryptococcal drug resistance, coupled with advances in genomics technologies and high-throughput screening methodologies, will catalyse innovation and accelerate antifungal drug discovery. Cryptococcosis is a serious fungal infection for which treatment options are limited. In this Review, Cowen and colleagues discuss the current antifungal treatments available for cryptococcal infections, the challenges in developing new treatments, and ongoing efforts to identify novel therapies.

AI snapshot

Written from the paper’s full text.

TL;DR

This review summarizes the limited current arsenal against cryptococcal infection, the intrinsic and adaptive resistance mechanisms used by *Cryptococcus* spp., and emerging therapeutic strategies. It highlights combination therapy, virulence-factor and stress-response targeting, drug repurposing, and immunotherapy/vaccine approaches as promising but still mostly preclinical or early-clinical directions.

Key findings

  • Cryptococcal meningitis causes an estimated 223,100 cases and 181,100 deaths annually, with 100% mortality if untreated; only three major antifungal classes are approved, and echinocandins have negligible activity against *Cryptococcus* spp.
  • Resistance involves genomic plasticity, including aneuploidy (most commonly chromosome 1 disomy involving *ERG11* and *AFR1*), hypermutator strains with ~200-fold higher mutation rates, and transposon movement; hypermutator *C. gattii* strains showed a 15% higher rate of flucytosine resistance.
  • Morphological changes contribute to resistance: thicker capsules and cell walls increase antifungal resistance, and titan cells are defined by >10 µm size, >4C ploidy, a thick cell wall, and a highly crosslinked capsule; ~20% of fungal cells in mouse lungs can become titan cells.
  • The phase III amphotericin B plus flucytosine regimen followed by fluconazole reduced 10-week mortality to 24%, compared with ~70% mortality in many low- and middle-income African countries; repurposed sertraline and tamoxifen failed to improve outcomes in later trials.

Methods

  • Narrative review synthesizing published literature on cryptococcal treatment, antifungal resistance mechanisms, drug discovery, and immunotherapy; no primary experimental data are reported.
  • Evidence discussed includes clinical trials, mouse infection models, genomic and chemical-genetic screens, and high-throughput compound screens, such as >300,000 compounds screened for fungicidal activity and ~3,600 bioactive compounds tested for synergy.
  • No systematic search strategy, inclusion criteria, or meta-analysis is described.

Limitations

  • Stated in the paper: treatment is limited by intrinsic echinocandin resistance, azole resistance, amphotericin B toxicity, flucytosine resistance and monotherapy limitations, and poor access/cost in resource-limited settings; several promising agents remain preclinical or have failed clinical trials, and 18B7 showed poor cerebrospinal fluid penetration.
  • Evident from the text: as a narrative review, it does not provide a systematic or quantitative synthesis, and its conclusions depend on the selected cited literature rather than a predefined review protocol.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1038/s41579-021-00511-0

Cites

161 of 161 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 203 cited sources checked · 0 supported · 0 flagged

  • Findingcitation

    A subset of Cryptococcus isolates have been identified as hypermutator strains, which contain mutations in core genes in the DNA mismatch repair pathway, most notably MSH2.

    “a subset of Cryptococcus isolates have been identified as hypermutator strains30,31, which contain mutations in core genes in the DNA mismatch repair pathway, most notably MSH2 (refs30,32,33)”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [30] Boyce, K. J. et al. Mismatch repair of DNA replication errors contributes to microevolution in the pathogenic fungus Cryptococcus neoformans. mBio 8, e00595-17 (2017). This report is one of the first of a hypermutator strain in clinical isolates, which has a fitness advantage owing to mutations in mismatch repair genes. source

      Not checked in the free run.

    • cites [31] Boyce, K. J., Cao, C., Xue, C. & Idnurm, A. A spontaneous mutation in DNA polymerase POL3 during in vitro passaging causes a hypermutator phenotype in Cryptococcus species. DNA Repair 86, 102751 (2020). source

      Not checked in the free run.

    • cites [32] Billmyre, R. B., Applen Clancey, S., Li, L. X., Doering, T. L. & Heitman, J. 5-Fluorocytosine resistance is associated with hypermutation and alterations in capsule biosynthesis in Cryptococcus. Nat. Commun. 11, 127 (2020). source

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  • Findingcitation

    A mutation in the proofreading domain of POL3 was shown to confer the hypermutator phenotype.

    “a mutation in the proofreading domain of POL3 (encoding the catalytic subunit of DNA polymerase δ) was also shown to confer the hypermutator phenotype31.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [31] Boyce, K. J., Cao, C., Xue, C. & Idnurm, A. A spontaneous mutation in DNA polymerase POL3 during in vitro passaging causes a hypermutator phenotype in Cryptococcus species. DNA Repair 86, 102751 (2020). source

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  • Findingcitation

    Laboratory studies have shown that selection for resistance to environmental agrochemicals, primarily through upregulation of ERG11 and drug efflux pumps, can lead to cross-resistance to clinically deployed antifungals.

    “Laboratory studies have shown that selection for resistance to environmental agrochemicals, primarily through the upregulation of the azole target gene ERG11 and drug efflux pumps, can lead to cross-resistance to clinically deployed antifungals19,20.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [19] Bastos, R. W. et al. From the environment to the host: how non-azole agrochemical exposure affects the antifungal susceptibility and virulence of Cryptococcus gattii. Sci. Total Environ. 681, 516–523 (2019). source

      Not checked in the free run.

    • cites [20] Bastos, R. W. et al. Environmental triazole induces cross-resistance to clinical drugs and affects morphophysiology and virulence of Cryptococcus gattii and C. neoformans. Antimicrob. Agents Chemother. 62, e01179-17 (2018). source

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  • Findingcitation

    Disomy of chromosome 1, which contains ERG11 and the predominant efflux pump gene AFR1, is the most common aneuploidy conferring azole heteroresistance.

    “most commonly involving disomy of chromosome 1, which contains ERG11 and the predominant efflux pump gene AFR1 (ref.17).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [17] Sionov, E., Lee, H., Chang, Y. C. & Kwon-Chung, K. J. Cryptococcus neoformans overcomes stress of azole drugs by formation of disomy in specific multiple chromosomes. PLoS Pathog. 6, e1000848 (2010). source

      Not checked in the free run.

  • Findingcitation

    Heteroresistance was first described in 1999, when researchers observed that a subset of Cryptococcus cells were able to grow at azole concentrations well above the inhibitory concentration in vitro.

    “This phenomenon was first described in 1999, when researchers observed that a subset of Cryptococcus cells were able to grow at azole concentrations well above the inhibitory concentration in vitro21.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [21] Mondon, P. et al. Heteroresistance to fluconazole and voriconazole in Cryptococcus neoformans. Antimicrob. Agents Chemother. 43, 1856–1861 (1999). source

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  • Classified as probably not a substantial claim. 5
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    Findingcitation

    Aneuploidy has been reported for chromosomes 6, 10, 11 and 14, although the specific genetic elements responsible for the selective advantage remain unclear.

    “Aneuploidy has been reported for other chromosomes, including chromosomes 6, 10, 11 and 14, although the specific genetic elements responsible for the selective advantage remain unclear17,22,25,26.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [17] Sionov, E., Lee, H., Chang, Y. C. & Kwon-Chung, K. J. Cryptococcus neoformans overcomes stress of azole drugs by formation of disomy in specific multiple chromosomes. PLoS Pathog. 6, e1000848 (2010). source

      Not checked in the free run.

    • cites [22] Stone, N. R. et al. Dynamic ploidy changes drive fluconazole resistance in human cryptococcal meningitis. J. Clin. Invest. 129, 999–1014 (2019). This paper presents the first clinical samples to demonstrate fluconazole heteroresistance due to aneuploidy, achieved through increased efflux levels. source

      Not checked in the free run.

    • cites [25] Ngamskulrungroj, P. et al. Characterization of the chromosome 4 genes that affect fluconazole-induced disomy formation in Cryptococcus neoformans. PLoS ONE 7, e33022 (2012).

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    Findingcitation

    Encochleated oral amphotericin B (CAmB) is effectively delivered to the central nervous system and displays antifungal efficacy in a mouse model.

    “A new form of encochleated oral amphotericin B (CAmB), where amphotericin B is encapsulated in a lipid-containing crystal nanoparticle, is effectively delivered to the central nervous system and displays antifungal efficacy in a mouse model11.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [11] Lu, R. et al. Efficacy of oral encochleated amphotericin B in a mouse model of cryptococcal meningoencephalitis. mBio 10, e00724-19 (2019).

      Not checked in the free run.

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    Findingcitation

    A phase III trial reported 10-week mortality of 24% for the combination regimen, a considerable improvement compared with the current ~70% mortality rate in many low- and middle-income countries in Africa.

    “The phase III trial reported 10-week mortality of 24%, which is a considerable improvement compared with the current ~70% mortality rate in many low- and middle-income countries in Africa6,14.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [6] Rajasingham, R. et al. Global burden of disease of HIV-associated cryptococcal meningitis: an updated analysis. Lancet Infect. Dis. 17, 873–881 (2017). source

      Not checked in the free run.

    • cites [14] Molloy, S. F. et al. Antifungal combinations for treatment of cryptococcal meningitis in Africa. N. Engl. J. Med. 378, 1004–1017 (2018). This seminal study provides guidelines adopted by the WHO for combatting cryptococcal infections. source

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    Findingcitation

    A clinical trial in HIV-positive patients with cryptococcal meningitis showed that combination of amphotericin B with flucytosine, followed by fluconazole, improved survival rates compared with amphotericin B alone and minimized toxic effects.

    “a clinical trial with patients who are HIV-positive and suffering from cryptococcal meningitis showed that the combination of amphotericin B with the fluorinated pyrimidine analogue flucytosine, followed by the triazole fluconazole, improved survival rates compared with amphotericin B alone and minimized toxic effects13.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [13] Day, J. N. et al. Combination antifungal therapy for cryptococcal meningitis. N. Engl. J. Med. 368, 1291–1302 (2013). This important clinical trial shows that the combination of amphotericin B and flucytosine improves survival of patients with cryptococcal meningitis. source

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  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingcitation

    An estimated 223,100 cases of cryptococcal meningitis occur globally each year, leading to 181,100 deaths.

    “An estimated 223,100 cases of cryptococcal meningitis occur globally each year, leading to 181,100 deaths6.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [6] Rajasingham, R. et al. Global burden of disease of HIV-associated cryptococcal meningitis: an updated analysis. Lancet Infect. Dis. 17, 873–881 (2017). source

      Not checked in the free run.

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    Findingcitation

    These mutations result in an ~200-fold higher mutation rate than in standard laboratory strains and preferentially affect genes containing homopolymer runs.

    “These mutations result in an ~200-fold higher mutation rate than in standard laboratory strains30 and preferentially affect genes containing homopolymer runs33.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [30] Boyce, K. J. et al. Mismatch repair of DNA replication errors contributes to microevolution in the pathogenic fungus Cryptococcus neoformans. mBio 8, e00595-17 (2017). This report is one of the first of a hypermutator strain in clinical isolates, which has a fitness advantage owing to mutations in mismatch repair genes. source

      Not checked in the free run.

    • cites [33] Billmyre, R. B., Clancey, S. A. & Heitman, J. Natural mismatch repair mutations mediate phenotypic diversity and drug resistance in Cryptococcus deuterogattii. eLife 6, e28802 (2017). source

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    Findingcitation

    The increase in chitin induces a T helper 2-type allergic response and cytokine release, rather than a protective T helper 1-type response, which leads to increased mortality in infected mice.

    “This increase in chitin induces a T helper 2-type allergic response and cytokine release, rather than a protective T helper 1-type response, which leads to increased mortality in infected mice152.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [152] Wiesner, D. L. et al. Chitin recognition via chitotriosidase promotes pathologic type-2 helper T cell responses to cryptococcal infection. PLoS Pathog. 11, e1004701 (2015). source

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    Findingcitation

    C. neoformans cells with thicker capsules exhibit amphotericin B resistance and enhanced virulence.

    “C. neoformans cells with thicker capsules exhibit amphotericin B resistance and enhanced virulence40,41”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [40] Cordoba, S., Afeltra, J. & Vitale, R. G. Evaluation of the in vitro activity of amphotericin B by time-kill curve methodology against large and small capsulate C. neoformans isolates. Diagn. Microbiol. Infect. Dis. 71, 260–262 (2011). source

      Not checked in the free run.

    • cites [41] Park, Y. D. et al. A role for LHC1 in higher order structure and complement binding of the Cryptococcus neoformans capsule. PLoS Pathog. 10, e1004037 (2014).

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    Findingcitation

    A genetic screen of more than 10,000 C. neoformans mutants identified CDC50 as integral to echinocandin resistance and demonstrated its involvement in maintaining lipid asymmetry of the phospholipid membrane.

    “A genetic screen of more than 10,000 C. neoformans mutants provided insight into this inherent resistance46. This screen identified CDC50 (encoding the β-subunit of a lipid flippase enzyme) as integral to echinocandin resistance and further demonstrated its involvement in maintaining lipid asymmetry of the phospholipid membrane46.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [46] Huang, W. et al. Lipid flippase subunit Cdc50 mediates drug resistance and virulence in Cryptococcus neoformans. mBio 7, e00478-16 (2016). This paper provides foundational genetic insights into the intrinsic echinocandin resistance of Cryptococcus. source

      Not checked in the free run.

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    Findingcitation

    The transition to titan cells can be triggered by muramyl dipeptide in serum and is regulated by USV101, STE3a and GPR5, which converge on the cAMP-PKA pathway.

    “This transition can be triggered by the bacterial peptidoglycan subunit muramyl dipeptide in serum and is regulated by USV101 (ref.149) as well as STE3a and GPR5 (ref.150), which converge on the cAMP–PKA pathway149,150.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [149] Dambuza, I. M. et al. The Cryptococcus neoformans titan cell is an inducible and regulated morphotype underlying pathogenesis. PLoS Pathog. 14, e1006978 (2018). source

      Not checked in the free run.

    • cites [150] Okagaki, L. H. et al. Cryptococcal titan cell formation is regulated by G-protein signaling in response to multiple stimuli. Eukaryot. Cell 10, 1306–1316 (2011). source

      Not checked in the free run.

  • May combine two claims.

    Findingcitation

    On titan cell formation, the polysaccharide capsule becomes condensed and highly crosslinked; the cell wall can increase in thickness from 50-100 nm to 2-3 μm; and cell wall composition is altered through an increase in chitin content and a decrease in glucan.

    “On titan cell formation, the polysaccharide capsule surrounding Cryptococcus cells becomes condensed and highly crosslinked151; the cell wall can increase in thickness from 50–100 nm to 2–3 µm (ref.147), and the cell wall composition is altered through an increase in chitin content and a decrease in glucan152.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [147] Zaragoza, O. et al. Fungal cell gigantism during mammalian infection. PLoS Pathog. 6, e1000945 (2010). source

      Not checked in the free run.

    • cites [151] Mukaremera, L. et al. Titan cell production in Cryptococcus neoformans reshapes the cell wall and capsule composition during infection. Cell Surf. 1, 15–24 (2018). source

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    • cites [152] Wiesner, D. L. et al. Chitin recognition via chitotriosidase promotes pathologic type-2 helper T cell responses to cryptococcal infection. PLoS Pathog. 11, e1004701 (2015). source

      Not checked in the free run.

  • May combine two claims.

    Findingcitation

    Cdc50 directly interacts with Crm1 and negatively regulates its expression.

    “Cdc50 directly interacts with Crm1 and negatively regulates its expression47.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [47] Cao, C., Wang, Y., Husain, S., Soteropoulos, P. & Xue, C. A mechanosensitive channel governs lipid flippase-mediated echinocandin resistance in Cryptococcus neoformans. mBio 10, e01952-19 (2019).

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  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    Treatment options for cryptococcosis remain limited, with only three major classes of drugs approved for clinical use.

    “Despite these alarming statistics, treatment options for cryptococcosis remain limited, with only three major classes of drugs approved for clinical use.”
    Quote in the paperNot a substantial claim

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    Premisecitation

    The traits of genomic plasticity and physiological adaptability can be inherited and are often transient, such that they are lost when the stress is removed.

    “These traits can be inherited, and are often transient, such that they are lost when the stress is removed17,18.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [17] Sionov, E., Lee, H., Chang, Y. C. & Kwon-Chung, K. J. Cryptococcus neoformans overcomes stress of azole drugs by formation of disomy in specific multiple chromosomes. PLoS Pathog. 6, e1000848 (2010). source

      Not checked in the free run.

    • cites [18] Sionov, E., Chang, Y. C., Garraffo, H. M. & Kwon-Chung, K. J. Heteroresistance to fluconazole in Cryptococcus neoformans is intrinsic and associated with virulence. Antimicrob. Agents Chemother. 53, 2804–2815 (2009). source

      Not checked in the free run.

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    Interpretationcitation

    Scarcity of flucytosine and amphotericin B has resulted in widespread use of the much less effective fluconazole monotherapy, which explains the dramatically high mortality rate in low- and middle-income African countries.

    “Scarcity of these two drugs has resulted in the widespread use of the much less effective fluconazole monotherapy, which explains the dramatically high mortality rate in these low- and middle-income African countries4,7.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [4] Perfect, J. R. et al. Clinical practice guidelines for the management of cryptococcal disease: 2010 update by the Infectious Diseases Society of America. Clin. Infect. Dis. 50, 291–322 (2010). source

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    • cites [7] Loyse, A. et al. Leave no one behind: response to new evidence and guidelines for the management of cryptococcal meningitis in low-income and middle-income countries. Lancet Infect. Dis. 19, e143–e147 (2019). source

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  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Immunocompromised individuals are most vulnerable to cryptococcal infection, but cryptococcal infections also occur in immunocompetent hosts.

    “immunocompromised individuals are most vulnerable, but there are also reports of cryptococcal infections in immunocompetent hosts4,5”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [4] Perfect, J. R. et al. Clinical practice guidelines for the management of cryptococcal disease: 2010 update by the Infectious Diseases Society of America. Clin. Infect. Dis. 50, 291–322 (2010). source

      Not checked in the free run.

    • cites [5] Kwon-Chung, K. J. et al. Cryptococcus neoformans and Cryptococcus gattii, the etiologic agents of cryptococcosis. Cold Spring Harb. Perspect. Med. 4, a019760 (2014). source

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    Premisecitation

    Cryptococcus spp. are intrinsically resistant to echinocandins and employ defences that enable resistance to azoles.

    “Treatment options for invasive cryptococcal infection are limited, given that Cryptococcus spp. are intrinsically resistant to echinocandins and that they employ an arsenal of defences that enable resistance to azoles2,8.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [2] Lee, Y., Puumala, E., Robbins, N. & Cowen, L. E. Antifungal drug resistance: molecular mechanisms in Candida albicans and beyond. Chem. Rev. https://doi.org/10.1021/acs.chemrev.0c00199 (2020). source

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    • cites [8] Denning, D. W. Echinocandin antifungal drugs. Lancet 362, 1142–1151 (2003). source

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    Premisecitation

    In low- and middle-income countries, flucytosine is not available owing to market failure and lack of in-country registration, and access to amphotericin B and its liposomal form is limited due to high cost and lack of safe intravenous administration.

    “In low- and middle-income countries, flucytosine is not available owing to market failure and lack of in-country registration, whereas access to amphotericin B and its liposomal form is limited due to the high cost and lack of safe intravenous administration7.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [7] Loyse, A. et al. Leave no one behind: response to new evidence and guidelines for the management of cryptococcal meningitis in low-income and middle-income countries. Lancet Infect. Dis. 19, e143–e147 (2019). source

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  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisenone given

    Cryptococcus neoformans and Cryptococcus gattii are the major species responsible for life-threatening cryptococcal meningitis.

    “C. neoformans and Cryptoccocus gattii are the major species responsible for life-threatening cryptococcal meningitis”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationcitation

    Heteroresistance has major clinical implications, as the proportion of resistant cells increases over the course of therapy, making this mechanism a major contributor to relapse during azole maintenance therapy.

    “Heteroresistance has major clinical implications, as the proportion of resistant cells increases over the course of therapy, making this mechanism a major contributor to relapse during azole maintenance therapy22,23.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [22] Stone, N. R. et al. Dynamic ploidy changes drive fluconazole resistance in human cryptococcal meningitis. J. Clin. Invest. 129, 999–1014 (2019). This paper presents the first clinical samples to demonstrate fluconazole heteroresistance due to aneuploidy, achieved through increased efflux levels. source

      Not checked in the free run.

    • cites [23] Rhodes, J. et al. A population genomics approach to assessing the genetic basis of within-host microevolution underlying recurrent cryptococcal meningitis infection. G3 7, 1165–1176 (2017). source

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    Premisecitation

    Amphotericin B has been the primary treatment for cryptococcal infection for more than half a century, despite causing substantial toxicity and limited availability due to economic and logistical constraints.

    “the polyene amphotericin B has been the primary treatment for cryptococcal infection for more than half a century, despite the fact that it causes substantial toxicity and that its availability is limited by economic and logistical constraints2,4”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [2] Lee, Y., Puumala, E., Robbins, N. & Cowen, L. E. Antifungal drug resistance: molecular mechanisms in Candida albicans and beyond. Chem. Rev. https://doi.org/10.1021/acs.chemrev.0c00199 (2020). source

      Not checked in the free run.

    • cites [4] Perfect, J. R. et al. Clinical practice guidelines for the management of cryptococcal disease: 2010 update by the Infectious Diseases Society of America. Clin. Infect. Dis. 50, 291–322 (2010). source

      Not checked in the free run.

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    Premisecitation

    The Cryptococcus polysaccharide capsule modulates immune responses, enhances pathogenicity and confers protection against oxidative stress.

    “The Cryptococcus polysaccharide capsule modulates immune responses, enhances pathogenicity and confers protection against oxidative stress55,56.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [55] Zaragoza, O. Basic principles of the virulence of Cryptococcus. Virulence 10, 490–501 (2019). source

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    • cites [56] McFadden, D., Zaragoza, O. & Casadevall, A. The capsular dynamics of Cryptococcus neoformans. Trends Microbiol. 14, 497–505 (2006). source

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  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationcitation

    Rapid genome alteration resulting in aneuploid cells has been proposed as an alternative mechanism of heteroresistance.

    “this rapid genome alteration resulting in aneuploid cells has been proposed as an alternative mechanism of heteroresistance43.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [43] Zafar, H., Altamirano, S., Ballou, E. R. & Nielsen, K. A titanic drug resistance threat in Cryptococcus neoformans. Curr. Opin. Microbiol. 52, 158–164 (2019). This seminal review summarizes the current understanding of the mechanisms underlying antifungal resistance of the Cryptococcus titan cell. source

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    Interpretationcitation

    Transposon-driven mutagenesis was enhanced in multiple strains at 37 °C compared with 30 °C, suggesting that the body temperature of a mammalian host may amplify this phenomenon.

    “transposon-driven mutagenesis was enhanced in multiple strains at 37 °C compared with that at 30 °C, suggesting that the body temperature of a mammalian host may amplify this phenomenon38.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [38] Gusa, A. et al. Transposon mobilization in the human fungal pathogen Cryptococcus is mutagenic during infection and promotes drug resistance in vitro. Proc. Natl Acad. Sci. USA 117, 9973–9980 (2020). This paper is the first description of transposon-mediated antifungal resistance in Cryptococcus spp. source

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    Premisecitation

    APX879, an FK506 analogue with an acetohydrazine substitution of the C22 carbonyl, has 70-fold lower immunosuppressive effects than FK506 while retaining antifungal activity.

    “enabling the design of APX879, an FK506 analogue with an acetohydrazine substitution of the C22 carbonyl, which has 70-fold lower immunosuppressive effects than FK506 while retaining antifungal activity77”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [77] Juvvadi, P. R. et al. Harnessing calcineurin–FK506–FKBP12 crystal structures from invasive fungal pathogens to develop antifungal agents. Nat. Commun. 10, 4275 (2019). This paper presents an excellent example of successful structure-guided drug design to develop fungal-specific calcineurin inhibitors. source

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    Premisecitation

    Melanin is produced by laccases, which are upregulated in C. neoformans clinical and environmental isolates.

    “Melanin is produced by laccases, which are upregulated in C. neoformans clinical and environmental isolates66”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [66] Lahiri, S. et al. In vitro expression of vital virulent genes of clinical and environmental isolates of Cryptococcus neoformans/gattii in endothelial cells of human blood–brain barrier. J. Mycol. Med. 29, 239–244 (2019). source

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    Premisecitation

    The fungal cell wall is important for cell integrity and for modulating the host immune response.

    “The fungal cell wall is a dynamic structure that is important not only for cell integrity but also for modulating the host immune response39.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [39] Garcia-Rubio, R., de Oliveira, H. C., Rivera, J. & Trevijano-Contador, N. The fungal cell wall: Candida, Cryptococcus, and Aspergillus species. Front. Microbiol. 10, 2993 (2019). source

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  • May combine two claims.

    Premisecitation

    Deletion of the gene encoding either Cxt1 or Lhc1 impairs capsule linkage and reduces the fungal burden in infections in mice.

    “Deletion of the gene encoding either of these enzymes impairs capsule linkage and reduces the fungal burden in infections in mice41,57.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [41] Park, Y. D. et al. A role for LHC1 in higher order structure and complement binding of the Cryptococcus neoformans capsule. PLoS Pathog. 10, e1004037 (2014).

      Not checked in the free run.

    • cites [57] Klutts, J. S. & Doering, T. L. Cryptococcal xylosyltransferase 1 (Cxt1p) from Cryptococcus neoformans plays a direct role in the synthesis of capsule polysaccharides. J. Biol. Chem. 283, 14327–14334 (2008). source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Phospholipase B1 (PLB1) facilitates Cryptococcus adherence to and invasion of the host cell, contributes to fungal cell wall integrity and degrades host cell membranes, thereby providing nutrients that support fungal survival.

    “For example, phospholipase B1 (encoded by PLB1) facilitates Cryptococcus adherence to and invasion of the host cell, contributes to fungal cell wall integrity and degrades host cell membranes, thereby providing nutrients that support fungal survival69,70.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [69] Wright, L. C. et al. Cryptococcal lipid metabolism: phospholipase B1 is implicated in transcellular metabolism of macrophage-derived lipids. Eukaryot. Cell 6, 37–47 (2007). source

      Not checked in the free run.

    • cites [70] Siafakas, A. R. et al. Cell wall-linked cryptococcal phospholipase B1 is a source of secreted enzyme and a determinant of cell wall integrity. J. Biol. Chem. 282, 37508–37514 (2007). source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The C. neoformans homologue of mTOR kinase, Tor1, is essential for Cryptococcus stress response signalling, virulence and fluconazole tolerance.

    “The C. neoformans homologue of mTOR kinase, Tor1, is essential for Cryptococcus stress response signalling, virulence84,85 and fluconazole tolerance (that is, the ability of a drug-susceptible organism to grow in the presence of an antifungal drug at concentrations above the minimum inhibitory concentration)86.”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [84] Lee, H., Khanal Lamichhane, A., Garraffo, H. M., Kwon-Chung, K. J. & Chang, Y. C. Involvement of PDK1, PKC and TOR signalling pathways in basal fluconazole tolerance in Cryptococcus neoformans. Mol. Microbiol. 84, 130–146 (2012). source

      Not checked in the free run.

    • cites [85] So, Y. S., Lee, D. G., Idnurm, A., Ianiri, G. & Bahn, Y. S. The TOR pathway pays pleiotropic roles in growth and stress responses of the fungal pathogen Cryptococcus neoformans. Genetics 212, 1241–1258 (2019). source

      Not checked in the free run.

    • cites [86] Berman, J. & Krysan, D. J. Drug resistance and tolerance in fungi. Nat. Rev. Microbiol. 18, 319–331 (2020). source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    An inhibitor of Hsp90 with 25-fold greater selectivity for Candida albicans Hsp90 than human HSP90 and aminopyrazole-substituted resorcylate amides with more than 30-fold greater selectivity for C. neoformans Hsp90 than human HSP90 have been identified.

    “An inhibitor of Hsp90 with 25-fold greater selectivity for Candida albicans Hsp90 than for human HSP90 (ref.81) and aminopyrazole-substituted resorcylate amides with more than 30-fold greater selectivity for C. neoformans Hsp90 than for human HSP90 (ref.82) have been identified”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites ref.81

      Not checked in the free run.

    • cites ref.82

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The secreted peptide Qsp1 is an important virulence determinant that acts as an autoregulatory signalling molecule and is transported into the fungal cell through Opt1 to initiate a diverse transcriptional response, including production of proteases and activation of cell wall integrity.

    “Finally, the secreted peptide Qsp1 is an important virulence determinant that acts as an autoregulatory signalling molecule and is transported into the fungal cell through Opt1 to initiate a diverse transcriptional response, including the production of proteases and activation of cell wall integrity72,73.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [72] Lee, H., Chang, Y. C., Nardone, G. & Kwon-Chung, K. J. TUP1 disruption in Cryptococcus neoformans uncovers a peptide-mediated density-dependent growth phenomenon that mimics quorum sensing. Mol. Microbiol. 64, 591–601 (2007). source

      Not checked in the free run.

    • cites [73] Homer, C. M. et al. Intracellular action of a secreted peptide required for fungal virulence. Cell Host Microbe 19, 849–864 (2016). source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Melanin is a major virulence factor that protects fungal cells from oxidative damage, antifungal assault and high temperature, and also modulates host immune responses.

    “In particular, melanin is a major virulence factor that protects fungal cells from oxidative damage, antifungal assault and high temperature, and also modulates host immune responses39.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [39] Garcia-Rubio, R., de Oliveira, H. C., Rivera, J. & Trevijano-Contador, N. The fungal cell wall: Candida, Cryptococcus, and Aspergillus species. Front. Microbiol. 10, 2993 (2019). source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Hsp90 inhibition impairs C. neoformans virulence traits, such as capsule assembly, and increases susceptibility to antifungal agents.

    “Hsp90 inhibition has been shown to impair C. neoformans virulence traits, such as capsule assembly, and increase susceptibility to antifungal agents79,80.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [79] Chatterjee, S. & Tatu, U. Heat shock protein 90 localizes to the surface and augments virulence factors of Cryptococcus neoformans. PLoS Negl. Trop. Dis. 11, e0005836 (2017). source

      Not checked in the free run.

    • cites [80] Cordeiro, R. A. et al. Inhibition of heat-shock protein 90 enhances the susceptibility to antifungals and reduces the virulence of Cryptococcus neoformans/Cryptococcus gattii species complex. Microbiology 162, 309–317 (2016). source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Deletion of CAP10, CAP60 and PXB1 blocks capsule production and leads to attenuated virulence.

    “Deletion of CAP10, CAP60 and PXB1 not only blocks capsule production but also leads to attenuated virulence52,58.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [52] Liu, O. W. et al. Systematic genetic analysis of virulence in the human fungal pathogen Cryptococcus neoformans. Cell 135, 174–188 (2008). source

      Not checked in the free run.

    • cites [58] Almeida, F., Wolf, J. M. & Casadevall, A. Virulence-associated enzymes of Cryptococcus neoformans. Eukaryot. Cell 14, 1173–1185 (2015). source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Mefloquine derivatives have improved in vitro antifungal activity and impede C. neoformans capsule formation and melanization.

    “but mefloquine derivatives have been identified that have improved in vitro antifungal activity and that impede C. neoformans capsule formation and melanization104.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [104] Montoya, M. C., Beattie, S., Alden, K. M. & Krysan, D. J. Derivatives of the antimalarial drug mefloquine are broad-spectrum antifungal molecules with activity against drug-resistant clinical isolates. Antimicrob. Agents Chemother. 64, e02331-19 (2020). source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Macrolides reduce capsule formation in C. gattii, impairing this key virulence trait and resulting in enhanced phagocytosis and inflammatory cytokine production by macrophages in culture.

    “Another example is the macrolides, commonly used antibiotics that target protein synthesis, which reduce capsule formation in C. gattii, impairing this key virulence trait and resulting in enhanced phagocytosis and inflammatory cytokine production by macrophages in culture59.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [59] Nakamura, S. et al. Macrolides inhibit capsule formation of highly virulent Cryptococcus gattii and promote innate immune susceptibility. Antimicrob. Agents Chemother. 63, e02364-18 (2019).

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Clinical trials with APX001 for the treatment of cryptococcosis are starting imminently, and phase II trials for invasive infections caused by Aspergillus spp. and Candida spp. are currently underway.

    “Clinical trials with APX001 for the treatment of cryptococcosis are starting imminently, and phase II trials for the treatment of invasive infections caused by Aspergillus spp. and Candida spp. are currently underway (NCT02957929, NCT02956499 and NCT04240886)”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites NCT02957929

      Not checked in the free run.

    • cites NCT02956499

      Not checked in the free run.

    • cites NCT04240886

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Gwt1 is an important virulence factor and the enzyme responsible for catalysing an early step in glycosylphosphatidylinositol (GPI)-anchor biosynthesis.

    “Gwt1, an important virulence factor and the enzyme responsible for catalysing an early step in glycosylphosphatidylinositol (GPI)-anchor biosynthesis96, has also emerged as a promising antifungal target.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [96] Zhao, Q. et al. GWT1 encoding an inositol acyltransferase homolog is required for laccase repression and stress resistance in the basidiomycete Cryptococcus neoformans. FEMS Yeast Res. 15, fov086 (2015). source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Tamoxifen displayed potent anti-cryptococcal activity in vitro and in a mouse model of disseminated cryptococcosis.

    “Similarly, tamoxifen, an oestrogen receptor modulator that is used to treat and prevent breast cancer and osteoporosis, also displayed potent anti-cryptococcal activity in vitro106 and in a mouse model of disseminated cryptococcosis107.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [106] Dolan, K. et al. Antifungal activity of tamoxifen: in vitro and in vivo activities and mechanistic characterization. Antimicrob. Agents Chemother. 53, 3337–3346 (2009). source

      Not checked in the free run.

    • cites [107] Butts, A. et al. Estrogen receptor antagonists are anti-cryptococcal agents that directly bind EF hand proteins and synergize with fluconazole in vivo. mBio 5, e00765-13 (2014). source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Of the 31 molecules with fungilytic activity, the largest class of inhibitors identified were antipsychotic agents, with general antiseptic agents following close behind.

    “Of these 31 molecules, the largest class of inhibitors identified were antipsychotic agents, with general antiseptic agents following close behind111.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [111] Butts, A. et al. A repurposing approach identifies off-patent drugs with fungicidal cryptococcal activity, a common structural chemotype, and pharmacological properties relevant to the treatment of cryptococcosis. Eukaryot. Cell 12, 278–287 (2013). source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    VT-1598 displays broad-spectrum activity against diverse fungi, including strong therapeutic potential in a mouse model of cryptococcal meningitis.

    “Similar to other clinically approved azoles, VT-1598 displays broad-spectrum activity against diverse fungi, including a strong therapeutic potential in a mouse model of cryptococcal meningitis101.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [101] Garvey, E. P., Sharp, A. D., Warn, P. A., Yates, C. M. & Schotzinger, R. J. The novel fungal CYP51 inhibitor VT-1598 is efficacious alone and in combination with liposomal amphotericin B in a murine model of cryptococcal meningitis. J. Antimicrob. Chemother. 73, 2815–2822 (2018). source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Fenbendazole displays potent in vitro activity against C. neoformans and C. gattii, as well as in vivo activity in a mouse model of cryptococcosis.

    “Fenbendazole displays potent in vitro activity against C. neoformans and C. gattii, as well as in vivo activity in a mouse model of cryptococcosis103.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [103] de Oliveira, H. C. et al. Fenbendazole controls in vitro growth, virulence potential, and animal infection in the Cryptococcus model. Antimicrob. Agents Chemother. 64, e00286-20 (2020). source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    A high-throughput screen of more than 300,000 compounds from the US NIH Molecular Libraries Program identified agents with fungicidal activity against C. neoformans, with secondary assays prioritizing compounds that interfered with fungal cell wall integrity.

    “A high-throughput screen of >300,000 compounds from the US National Institutes of Health (NIH) Molecular Libraries Program was undertaken to identify agents with fungicidal activity against C. neoformans, where secondary assays prioritized compounds that interfered with fungal cell wall integrity91.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [91] Hartland, K. et al. High-throughput screen in Cryptococcus neoformans identifies a novel molecular scaffold that inhibits cell wall integrity pathway signaling. ACS Infect. Dis. 2, 93–102 (2016). source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Systematic analysis of dark chemical matter revealed that these compounds are not biologically inert and identified a potent inhibitor of C. neoformans growth in vitro.

    “Systematic analysis of these apparently inactive compounds revealed that they are not biologically inert, and even identified a potent inhibitor of C. neoformans growth in vitro87.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [87] Wassermann, A. M. et al. Dark chemical matter as a promising starting point for drug lead discovery. Nat. Chem. Biol. 11, 958–966 (2015). This paper reaffirms that dark chemical matter compounds can be attractive lead compounds and demonstrates the potential for anti-cryptococcal drug discovery. source

      Not checked in the free run.

    • Rests on an assumption: Most compound libraries have been designed to maximize drug-like properties with respect to mammalian targets and physiology, whereas antifungal drugs require unique physicochemical properties.

  • May combine two claims.

    Premisecitation

    The efficacy of fenbendazole was attributed to its growth-inhibitory properties, its inhibition of Cryptococcus virulence determinants and its inhibition of fungal proliferation inside macrophages.

    “The efficacy of fenbendazole was attributed to its growth-inhibitory properties, its inhibition of Cryptococcus virulence determinants and its inhibition of fungal proliferation inside macrophages103.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [103] de Oliveira, H. C. et al. Fenbendazole controls in vitro growth, virulence potential, and animal infection in the Cryptococcus model. Antimicrob. Agents Chemother. 64, e00286-20 (2020). source

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    Combination therapy has the potential to confer enhanced efficacy and fungal selectivity while reducing vulnerability to the evolution of resistance.

    “Combination therapy has the potential to confer enhanced efficacy and fungal selectivity while reducing vulnerability to the evolution of resistance2.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [2] Lee, Y., Puumala, E., Robbins, N. & Cowen, L. E. Antifungal drug resistance: molecular mechanisms in Candida albicans and beyond. Chem. Rev. https://doi.org/10.1021/acs.chemrev.0c00199 (2020). source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The amphipathic nature of this motif permits crossing of biological membranes, a property important for traversing the blood-brain barrier and accessing cryptococcal cells that reside within the lysosome or phagolysosome of host cells.

    “The amphipathic nature of this motif permits the crossing of biological membranes, a property that is important for traversing the blood–brain barrier and accessing cryptococcal cells that reside within the lysosome or phagolysosome of host cells114.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [114] Banks, W. A. Characteristics of compounds that cross the blood–brain barrier. BMC Neurol. 9, S3 (2009). source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Heat-killed mutant strains induce strong T helper 1 cell responses, resulting in full protection against C. neoformans challenge.

    “Heat-killed mutant strains have also been reported to induce strong T helper 1 cell responses, resulting in full protection against C. neoformans challenge65,136.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [65] Upadhya, R. et al. Induction of protective immunity to cryptococcal infection in mice by a heat-killed, chitosan-deficient strain of Cryptococcus neoformans. mBio 7, e00547-16 (2016). source

      Not checked in the free run.

    • cites [136] Zhai, B. et al. Development of protective inflammation and cell-mediated immunity against Cryptococcus neoformans after exposure to hyphal mutants. mBio 6, e01433-15 (2015). source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Mice vaccinated with glucan particles containing cryptococcal antigens mounted antigen-specific T cell responses and sustained protection against cryptococcosis.

    “Specifically, mice vaccinated with glucan particles containing cryptococcal antigens mounted antigen-specific T cell responses and sustained protection against cryptococcosis138.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [138] Specht, C. A. et al. Vaccination withrecombinant Cryptococcus proteins in glucan particles protects mice against cryptococcosis in a manner dependent upon mouse atrain and cryptococcal species. mBio 8, e01872-17 (2017). source

      Not checked in the free run.

  • The quote only partly states this claim.

    Premisecitation

    An avirulent but live mutant strain of C. neoformans lacking sterylglucosidase (sglΔ) induced protective effects similar to H99γ.

    “Similar protective effects were seen with an avirulent but live mutant strain of C. neoformans lacking sterylglucosidase (sglΔ)134,135.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [134] Wormley, F. L. Jr., Perfect, J. R., Steele, C. & Cox, G. M. Protection against cryptococcosis by using a murine γ interferon-producing Cryptococcus neoformans strain. Infect. Immun. 75, 1453–1462 (2007). source

      Not checked in the free run.

    • cites [135] Rella, A. et al. Role of sterylglucosidase 1 (Sgl1) on the pathogenicity of Cryptococcus neoformans: potential applications for vaccine development. Front. Microbiol. 6, 836 (2015). source

      Not checked in the free run.

51 of 51

  • The paper relies on this without support.

    Virulence factors are not required for the growth of the pathogen but are crucial for causing disease.

    “Targeting virulence factors, which are not required for the growth of the pathogen but, instead, are crucial for causing disease, opens up a plethora of new targets for drug development.”

  • The paper relies on this without support.

    The fungal cell wall is absent from mammalian cells.

    “This structure is absent from mammalian cells, and therefore great efforts have been made to develop antifungal agents that target this unique structure directly or that impair its biosynthesis.”

  • The paper relies on this without support.

    Most compound libraries have been designed to maximize drug-like properties with respect to mammalian targets and physiology, whereas antifungal drugs require unique physicochemical properties.

    “The development of new antifungal molecules remains a considerable challenge, as most compound libraries have been designed to maximize their ‘drug-like’ properties with respect to mammalian targets and physiology, whereas antifungal drugs require unique physicochemical properties, owing in part to the need for these molecules to transverse the fungal cell wall.”

  • The paper relies on this without support.

    Antifungal molecules need good central nervous system penetration and should be able to be administered orally to ensure widespread access within developing countries with limited resources.

    “Furthermore, because of the unique neurological features of cryptococcal disease, antifungal molecules are needed that have good central nervous system penetration, and they should be able to be administered orally to ensure widespread access within developing countries with limited resources.”
4 of 4

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • 18B7's development stage conflicts with its reported clinical trial

    Minor

    Table 1 lists monoclonal antibody 18B7 at the basic-research stage, but the text says it was evaluated in a phase I/II trial.

  • Serotype A is assigned to two different varieties

    Minor

    The paper first assigns serotype A to C. neoformans var. grubii, then assigns serotype A isolates to var. neoformans.

2 of 2

Cites

Flagged first, then by citations

Research works printed but not linked: 1

  1. Chen, Y. et al. Microevolution of serial clinical isolates of Cryptococcus neoformans var. grubii and C. gattii. mBio 8, e00166-17 (2017).

Cited by

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Related

Authors
Iyer, K. R., Revie, N. M., Fu, C., Robbins, N., & Cowen, L. E.
Affiliations
University of Toronto (CA)
Corresponding author
Cowen, Leah E.
ORCID
Venue
Nature Reviews Microbiology
Publisher
Springer Science and Business Media LLC
Published
2021-02-08
Volume
19
Issue
7
Pages
454-466
ISSN
  • 1740-1526 (ISSN-L)
  • 1740-1534
DOI
10.1038/s41579-021-00511-0
PMC
PMC7868659
OpenAlex
W3127236674
Semantic Scholar
b3debc518effc79a3f7043a7e5e11118b45e854d
Cited by
363
References
161
Citations by year
2026: 50 · 2025: 84 · 2024: 82 · 2023: 55 · 2022: 55 · 2021: 35 · 2020: 1
FWCI
8.75
Type
journal article
Language
en
Open access
Licence
Locations
  • Nature Reviews Microbiology (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • Canadian Institute for Advanced Research
  • National Institutes of Health (NIAID R21)
  • Canadian Institutes of Health Research (FDN154288)
  • National Institute of Allergy and Infectious Diseases (R01AI127375, R21AI141080, R01AI120958)
Topics
  • Health Sciences › Medicine › Epidemiology › Fungal Infections and Studies
  • Health Sciences › Medicine › Infectious Diseases › Antifungal resistance and susceptibility
  • Life Sciences › Immunology and Microbiology › Microbiology › Bacterial Infections and Vaccines
Keywords
cryptococcosis, cryptococcal meningitis, Cryptococcus neoformans, Cryptococcus gattii, antifungal resistance, echinocandins, combination therapy, stress response pathways, antifungal drug discovery, host-pathogen interaction
MeSH terms
Antifungal Agents, Cell Wall, Cryptococcosis, Cryptococcus, Drug Resistance, Fungal, Virulence Factors, Echinocandins, Fungal Capsules, Fungal Polysaccharides

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Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-09.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-09.

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