Drug resistance and tolerance in fungi.

In the paper

“For example, the 90-day mortality rate for recipients of solid organ transplants who develop candidemia [G] is between 22%-44%, depending on the Candida species4.”

What the sources say

• Partly supported

  Section 3.2 reports 90-day mortality of 22.6%–44% by Candida species among organ transplant recipients with invasive candidiasis. The cohort includes infection sites other than the bloodstream, so these figures are not established specifically for recipients with candidemia. (LLM, conf=0.88)

  cites [4] Andes, D. R. et al. The epidemiology and outcomes of invasive Candida infections among organ transplant recipients in the United States: results of the Transplant-Associated Infection Surveillance Network (TRANSNET). Transpl. Infect. Dis. 18, 921–931 (2016). sourceExperimental — accuracy not yet measured

In the paper

“Although relatively low levels of resistance for most Candida species have been described, the outcomes for candidemia remain poor, as high levels of mortality (15%-50%) have been associated with candida infections7.”

What the sources say

• Partly supported

  The introductory passage following the Abstract’s Conclusions says antifungal-resistant Candida isolates remain uncommon and invasive fungal infections are associated with high mortality. It does not give a 15%–50% mortality range or state a mortality rate specifically for candidemia; searches for that range and for candidemia mortality found no supporting passage. (LLM, conf=0.87)

  cites [7] Pfaller, M. A., Diekema, D. J., Turnidge, J. D., Castanheira, M. & Jones, R. N. Twenty years of the SENTRY antifungal surveillance program: results for Candida species from 1997–2016. Open Forum Infect. Dis. 6, S79–S94 (2019). sourceExperimental — accuracy not yet measured

In the paper

“Subpopulations of tolerant cells grow slowly in drug concentrations above the MIC, which is usually visually evident after time periods longer than the standard 24 h for MIC measurements.”

What the sources say

• Supported

  The Results section defines the standard MIC measurement at 24 h and says tolerance is commonly monitored at 48 h, when the authors measured growth above the MIC. The Subpopulation growth dynamics section confirms that only a proportion of cells grow at supra-MIC concentrations and that their growth slows in the presence of fluconazole. Page numbers are unavailable in our copy. (LLM, conf=0.91)

  cites [9] Rosenberg, A. et al. Antifungal tolerance is a subpopulation effect distinct from resistance and is associated with persistent candidemia. Nat. Commun. 9, 2470 (2018). This article provides a quantitative characterization of fluconazole tolerance in C. albicans, distinguishing it from resistance and highlighting its phenotypic heterogeneity and association with subpopulation growth, and sensitivity to adjuvant drugs. source

In the paper

“C. auris appears to rapidly acquire resistance or tolerance to echinocandins as well polyenes1,42, leaving few, if any, treatment options.”

What the sources say

• ?Not checked — no full text of the sourcecites [1] Arendrup, M. C. & Patterson, T. F. Multidrug-resistant Candida: epidemiology, molecular mechanisms, and treatment. J. Infect. Dis. 216, S445–S451 (2017). source
• ?Could not verify

  The Results and Discussion (page unavailable) describe antifungal susceptibility for a single C. auris isolate, but do not report resistance developing over time. Table 1 (page unavailable) lists susceptibility results for other drug classes, not echinocandins or polyenes. Searches for rapid acquisition of resistance, echinocandins, polyenes, and treatment options found no passage supporting the claim. (LLM, conf=0.76)

  cites [42] Satoh, K. et al. Candida auris sp. nov., a novel ascomycetous yeast isolated from the external ear canal of an inpatient in a Japanese hospital. Microbiol. Immunol. 53, 41–44 (2009). sourceExperimental — accuracy not yet measured

In the paper

“Many ERG11 mutations seem to interfere with drug binding and to decrease susceptibility in an additive manner36.”

What the sources say

• Partly supported

  The introduction states that ERG11 point mutations reduce azole binding to their target, supporting the drug-binding part of the claim. The Discussion describes lower azole susceptibility with two mutant UPC2 alleles than with one, but does not say that ERG11 mutations reduce susceptibility additively. Page numbers were not available in our copy. (LLM, conf=0.86)

  cites [36] Flowers, S. A. et al. Gain-of-function mutations in UPC2 are a frequent cause of ERG11 upregulation in azole-resistant clinical isolates of Candida albicans. Eukaryot. Cell 11, 1289–1299 (2012). This study establishes that gain-of-function mutations in UPC2, the key regulator of ergosterol biosynthesis gene expression, are a source of clinically important fluconazole resistance. Previously, only transcriptional regulators of efflux pump expression were known to do so. sourceExperimental — accuracy not yet measured

In the paper

“Antifungal drug resistance rates in Candida species are dynamic and variable between medical institutions and countries7.”

What the sources say

• Partly supported

  The Results section reports changes in fluconazole resistance over time for several Candida species and different resistance rates across geographic regions (Tables 3 and 4; page not provided). It does not report resistance rates by individual medical institution or country, so those specific comparisons are not established by this source. (LLM, conf=0.86)

  cites [7] Pfaller, M. A., Diekema, D. J., Turnidge, J. D., Castanheira, M. & Jones, R. N. Twenty years of the SENTRY antifungal surveillance program: results for Candida species from 1997–2016. Open Forum Infect. Dis. 6, S79–S94 (2019). sourceExperimental — accuracy not yet measured

In the paper

“Mutations in ERG11 have also been observed in Candida spp. and over 100 different ERG11 alleles have been described35.”

What the sources say

• Partly supported

  The Results section (“Conservation of known drug resistance and virulence related genes”; page unavailable) reports ERG11 mutations in Candida auris isolates and identifies a mutation also found in C. pseudohaemulonii. It does not report more than 100 distinct ERG11 alleles; searches for that number and for ERG11 allele counts found no supporting passage. (LLM, conf=0.88)

  cites [35] Munoz, J. F. et al. Genomic insights into multidrug-resistance, mating and virulence in Candida auris and related emerging species. Nat. Commun. 9, 5346 (2018). sourceExperimental — accuracy not yet measured

In the paper

“Like tolerance, trailing growth is sensitive to growth conditions17–19; the degree of sensitivity to these conditions differs for different clinical isolates9,(reviewed in 20), and leads to considerable laboratory-to-laboratory variation in the estimation of trailing growth.”

What the sources say

• ?Not checked — no full text of the sourcecites [17] Coenye, T., De Vos, M., Vandenbosch, D. & Nelis, H. Factors influencing the trailing endpoint observed in Candida albicans susceptibility testing using the CLSI procedure. Clin. Microbiol. Infect. 14, 495–497 (2008). source
• ?Not checked — no full text of the sourcecites [18] Agrawal, D., Patterson, T. F., Rinaldi, M. G. & Revankar, S. G. Trailing end-point phenotype of Candida spp. in antifungal susceptibility testing to fluconazole is eliminated by altering incubation temperature. J. Med. Microbiol. 56, 1003–1004 (2007). source
• ?Not checked — no full text of the sourcecites [19] Marr, K. A., Rustad, T. R., Rex, J. H. & White, T. C. The trailing end point phenotype in antifungal susceptibility testing is pH dependent. Antimicrob. Agents Chemother. 43, 1383–1386 (1999). source
• Supported

  The Results (page unavailable) report that pH, temperature, and growth medium affect measures of trailing growth, and that strains differ in their sensitivity to medium changes. The paper says consistent assay conditions are needed for reproducible results. The citing sentence's laboratory-to-laboratory variation is an inference from those findings, rather than a variation measured directly in the source. (LLM, conf=0.88)

  cites [9] Rosenberg, A. et al. Antifungal tolerance is a subpopulation effect distinct from resistance and is associated with persistent candidemia. Nat. Commun. 9, 2470 (2018). This article provides a quantitative characterization of fluconazole tolerance in C. albicans, distinguishing it from resistance and highlighting its phenotypic heterogeneity and association with subpopulation growth, and sensitivity to adjuvant drugs. source
• Partly supported

  Section 6 reports trailing growth at neutral pH but not low pH, supporting sensitivity to growth conditions, while cautioning that the media also differed. Section 4 describes different degrees of trailing growth among C. albicans isolates. Neither passage establishes that isolates differ in their sensitivity to growth conditions or that this causes laboratory-to-laboratory variation in trailing-growth measurements; page numbers were not available in our copy. (LLM, conf=0.82)

  cites [20] Delarze, E. & Sanglard, D. Defining the frontiers between antifungal resistance, tolerance and the concept of persistence. Drug Resist. Updat. 23, 12–19 (2015). sourceExperimental — accuracy not yet measured

In the paper

“Furthermore, higher tolerance in bacterial isolates is associated with longer lag phase length, whereas fungal isolates with higher tolerance levels have shorter lag phase length (measured as time required for colonies to become visible13) relative to those with lower tolerance levels9.”

What the sources say

• Supported

  Citation 13 is attached to the parenthetical definition of the measurement, not the bacterial–fungal tolerance comparison, which is cited to source 9. In Representative Results (Figure 5; page unavailable), ScanLag defines a colony’s “appearance time” as the time when it is detected, supporting the cited definition of time until colonies become visible. (LLM, conf=0.93)

  cites [13] Levin-Reisman, I., Fridman, O. & Balaban, N. Q. ScanLag: high-throughput quantification of colony growth and lag time. J. Vis. Exp. https://doi.org/10.3791/51456 (2014). source
• Partly supported

  The Discussion says antibacterial tolerance generally involves a longer lag phase. In Subpopulation growth dynamics, highly tolerant fungal isolates had shorter lag times in liquid assays with drug and a shorter drug-induced delay in colony appearance. The claim omits the drug condition and implies that colony appearance time itself was shorter; the paper says lag-phase duration did not correlate with tolerance in growth measurements without drug. (LLM, conf=0.85)

  cites [9] Rosenberg, A. et al. Antifungal tolerance is a subpopulation effect distinct from resistance and is associated with persistent candidemia. Nat. Commun. 9, 2470 (2018). This article provides a quantitative characterization of fluconazole tolerance in C. albicans, distinguishing it from resistance and highlighting its phenotypic heterogeneity and association with subpopulation growth, and sensitivity to adjuvant drugs. sourceExperimental — accuracy not yet measured

In the paper

“Whereas tolerance is generally due to substantial subpopulations of cells (5-90%) that grow in drug, antifungal heteroresistance or persistence involve rare cells (generally <<1%) that transiently survive high concentrations of antifungal drugs14.”

What the sources say

• Partly supported

  The Introduction describes persisters as a small, nongrowing subpopulation that survives high antifungal doses, supporting that part of the claim. It defines tolerance as survival after transient exposure, not growth in drug, and attributes growth in drug to resistant isolates. The cited passages give neither the 5–90% nor the generally <<1% range, and do not address heteroresistance; the section on in vivo persistence reports persister frequencies of up to 9% in some strains. (LLM, conf=0.88)

  cites [14] Wuyts, J., Van Dijck, P. & Holtappels, M. Fungal persister cells: the basis for recalcitrant infections? PLoS Pathog. 14, e1007301 (2018). sourceExperimental — accuracy not yet measured

In the paper

“First, tolerance of an isolate is relatively reproducible, with differences in tolerance levels between isolates presumed to be affected by intrinsic genetic differences between those isolates. (Fig. 1A).”

What the sources say

• Supported

  The Results passage says tolerance measurements were reproducible and stable for a given isolate. The Discussion says the size of the tolerant subpopulation is a heritable feature of a strain and predicts that tolerance differs between genetic backgrounds and growth conditions. The supplied passages do not give page numbers. (LLM, conf=0.90)

  cites [9] Rosenberg, A. et al. Antifungal tolerance is a subpopulation effect distinct from resistance and is associated with persistent candidemia. Nat. Commun. 9, 2470 (2018). This article provides a quantitative characterization of fluconazole tolerance in C. albicans, distinguishing it from resistance and highlighting its phenotypic heterogeneity and association with subpopulation growth, and sensitivity to adjuvant drugs. source

In the paper

“The degree of tolerance correlates with the size of the subpopulation of cells that grow above the MIC, and the rate at which such cells form visible colonies at supra-MIC concentrations9.”

What the sources say

• Supported

  In “Subpopulation growth dynamics” (Fig. 2a), the proportion of cells forming colonies above the MIC correlates with tolerance measured as FoG. The same section (Fig. 2f–g) reports that high-FoG isolates have a shorter delay before colonies appear on fluconazole and that this delay correlates with FoG levels. Page numbers are unavailable in our copy. (LLM, conf=0.93)

  cites [9] Rosenberg, A. et al. Antifungal tolerance is a subpopulation effect distinct from resistance and is associated with persistent candidemia. Nat. Commun. 9, 2470 (2018). This article provides a quantitative characterization of fluconazole tolerance in C. albicans, distinguishing it from resistance and highlighting its phenotypic heterogeneity and association with subpopulation growth, and sensitivity to adjuvant drugs. source

In the paper

“Upon exposure to fluconazole, all cells undergo 1-3 rounds of division before growth arrest9,58; tolerant cells in the population resume growth several hours later, whereas non-tolerant cells arrest for considerably longer and only resume division in the absence of the drug.”

What the sources say

• Partly supported

  Split into 2 atoms — 0 confirmed, 2 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

  cites [9] Rosenberg, A. et al. Antifungal tolerance is a subpopulation effect distinct from resistance and is associated with persistent candidemia. Nat. Commun. 9, 2470 (2018). This article provides a quantitative characterization of fluconazole tolerance in C. albicans, distinguishing it from resistance and highlighting its phenotypic heterogeneity and association with subpopulation growth, and sensitivity to adjuvant drugs. sourceExperimental — accuracy not yet measured
• ?Could not verify

  Split into 2 atoms — 0 confirmed, 0 partially supported, 0 disputed, 0 misattributed, 2 unverifiable. Expand the claim to see per-atom verdicts.

  cites [58] Forche, A. et al. The parasexual cycle in Candida albicans provides an alternative pathway to meiosis for the formation of recombinant strains. PLoS Biol. 6, e110 (2008). sourceExperimental — accuracy not yet measured

In the paper

“Adjuvant [G] drugs and mutations that affect several stress-responsive pathways often reduce tolerance9 (Box 5); and adjuvants reduce tolerance to similar baseline levels irrespective of the tolerance level of the isolate9.”

What the sources say

• Supported

  In the Results section on adjuvant fluconazole combinations (page not available), the paper reports that most adjuvants significantly reduced tolerance and that the combinations cleared tolerance across the clinical isolates tested. The same section reports that genes in several stress-response pathways primarily affected tolerance; together with the across-isolate result, this supports the paraphrase. (LLM, conf=0.87)

  cites [9] Rosenberg, A. et al. Antifungal tolerance is a subpopulation effect distinct from resistance and is associated with persistent candidemia. Nat. Commun. 9, 2470 (2018). This article provides a quantitative characterization of fluconazole tolerance in C. albicans, distinguishing it from resistance and highlighting its phenotypic heterogeneity and association with subpopulation growth, and sensitivity to adjuvant drugs. source

In the paper

“Homozygosis of this ERG11 allele was persistent (retained in the infecting population for more than 8 months55), consistent with the notion that mutations in ERG11 promote pathogen survival under drug selection56.”

What the sources say

• Supported

  The citation to this paper is attached to the idea that ERG11 mutations may aid survival under drug selection, not to the preceding eight-month duration. The Results section (‘LOH events are commonly associated with increased resistance’; page unavailable) describes a persistent homozygous ERG11 change and identifies ERG11 as a fluconazole drug target. The Discussion (page unavailable) reports ERG11 mutation LOH in three patients, while leaving its independent effect on resistance unresolved; this supports the citing sentence’s cautious wording. (LLM, conf=0.88)

  cites [55] Ford, C. B. et al. The evolution of drug resistance in clinical isolates of Candida albicans. eLife 4, e00662 (2015). source
• Partly supported

  The paper’s opening passage says alterations in the azole target enzyme can contribute to resistance, which supports the general link between target-enzyme changes and drug resistance. Our copy does not report that this ERG11 allele became homozygous or persisted for more than eight months, nor does it establish that the mutation promoted survival under drug selection. (LLM, conf=0.75)

  cites [56] White, T. C. Increased mRNA levels of ERG16, CDR, and MDR1 correlate with increases in azole resistance in Candida albicans isolates from a patient infected with human immunodeficiency virus. Antimicrob. Agents Chemother. 41, 1482–1487 (1997). This article presents the first detailed study of the molecular mechanisms underlying the development of fluconazole resistance over time in patients. It is a landmark study because of its patient-based approach and because it yielded strains that are still under study today. sourceExperimental — accuracy not yet measured

In the paper

“Phenotypic differences between clinical isolates involves many thousands, to tens of thousands of SNPs, and is also evident with phenotypes such as biofilm formation and its dependence upon specific transcription factors72.”

What the sources say

• Partly supported

  The Results and Discussion report an average of 65,629 heterozygous SNPs per isolate and describe phenotypic differences among isolates. That count is within isolates, not a measure of SNP differences between isolates. The paper links transcription factors to fitness and morphogenesis, but the passages found do not establish differences in biofilm formation or its dependence on particular transcription factors (Results and Discussion; page unavailable). (LLM, conf=0.85)

  cites [72] Ropars, J. et al. Gene flow contributes to diversification of the major fungal pathogen Candida albicans. Nat. Commun. 9, 2253 (2018). sourceExperimental — accuracy not yet measured

In the paper

“Furthermore, both LOH and aneuploidy occur at much higher frequency (2-4-fold) than point mutations59, and are readily detected following a single passage through the bloodstream or oral cavity of a mouse61–63.”

What the sources say

• ?Could not verify

  The citation to this paper is attached to detection after a single mouse passage, not to the 2–4-fold comparison, which cites reference 59. The Results section, “Trimeras Form During Exposure to FLC Within the Host” (page unavailable), reports trimera-like cells in fluconazole-treated mouse ear tissue after 48 hours; it does not report detecting LOH or aneuploidy after passage through the bloodstream or oral cavity. Searches for those routes and for mouse-passage detection found no supporting passage. (LLM, conf=0.76)

  cites [59] Harrison, B. D. et al. A tetraploid intermediate precedes aneuploid formation in yeasts exposed to fluconazole. PLoS Biol. 12, e1001815 (2014). sourceExperimental — accuracy not yet measured
• Partly supported

  The Genome Architecture and Environmental Pressures section says LOH was more frequent during bloodstream passage and oral-cavity infection than in vitro. The paper also reports aneuploidy after mouse gastrointestinal passage, but does not establish that both changes were readily detected after a single passage through the bloodstream or oral cavity. The 2–4-fold comparison is attached to a different citation (59). (LLM, conf=0.85)

  cites [61] Ene, I. V. et al. Global analysis of mutations driving microevolution of a heterozygous diploid fungal pathogen. Proc. Natl Acad. Sci. USA 115, E8688–E8697 (2018). sourceExperimental — accuracy not yet measured
• Supported

  The citation to this source concerns detection after mouse passage, not the 2–4-fold comparison, which the sentence cites separately. The Abstract (page not available) reports LOH and aneuploidy after passage through the mouse oral cavity and describes earlier findings of both after passage in a mouse bloodstream-infection model. (LLM, conf=0.90)

  cites [62] Forche, A. et al. Rapid phenotypic and genotypic diversification after exposure to the oral host niche in Candida albicans. Genetics 209, 725–741 (2018). source
• Partly supported

  Materials and Methods describes isolates obtained after passage through mice in a model of bloodstream-disseminated infection, and Results and Discussion reports LOH and chromosome-size changes in those isolates. The paper does not establish aneuploidy or examine passage through the oral cavity. The 2–4-fold comparison is attached to a different citation in the citing sentence, so it is not assessed here. (LLM, conf=0.86)

  cites [63] Forche, A., May, G. & Magee, P. T. Demonstration of loss of heterozygosity by single-nucleotide polymorphism microarray analysis and alterations in strain morphology in Candida albicans strains during infection. Eukaryot. Cell 4, 156–165 (2005). sourceExperimental — accuracy not yet measured

In the paper

“it leaves the polyene amphotericin B, which is toxic8, as the only treatment option for these infections.”

What the sources say

• ?Not checked — no full text of the sourcecites [8] Lepak, A. J. & Andes, D. R. Antifungal pharmacokinetics and pharmacodynamics. Cold Spring Harb. Perspect. Med. 5, a019653 (2014). source
• ?Could not verify

  Citation 8 is attached specifically to the assertion that amphotericin B is toxic. The Introduction (page unavailable) discusses multidrug-resistant C. glabrata infections but does not address amphotericin B or its toxicity; searches for amphotericin B and toxicity found no supporting passage. The Introduction instead says there are no treatment options for these infections, rather than identifying amphotericin B as the only option. (LLM, conf=0.76)

  cites [71] Shor, E., Schuyler, J. & Perlin, D. S. A novel, drug resistance-independent, fluorescence-based approach to measure mutation rates in microbial pathogens. mBio 10, e00120–19 (2019). sourceExperimental — accuracy not yet measured

In the paper

“Echinocandin resistance is less prevalent than azole resistance (less than 1% of C. albicans infections7, but up to 10% of C. glabrata infections)66.”

What the sources say

• Partly supported

  In the Results section on echinocandin resistance (page unavailable), the paper reports 1.7%–3.5% resistance among C. glabrata isolates overall and cites earlier findings of 8%–9% specifically among fluconazole-resistant bloodstream isolates. Thus, “up to 10%” is plausible for that restricted subgroup, but the citing sentence omits the qualifier and presents it as a rate for C. glabrata infections generally. (LLM, conf=0.86)

  cites [7] Pfaller, M. A., Diekema, D. J., Turnidge, J. D., Castanheira, M. & Jones, R. N. Twenty years of the SENTRY antifungal surveillance program: results for Candida species from 1997–2016. Open Forum Infect. Dis. 6, S79–S94 (2019). sourceExperimental — accuracy not yet measured
• Supported

  The Echinocandin Resistance section reports caspofungin resistance in 10.3% of C. glabrata isolates from cancer patients; the Azole Resistance section reports fluconazole resistance in 20.5%. That supports the approximate 10% figure and the comparison. The C. albicans figure is attached to a different citation in the citing sentence. (LLM, conf=0.88)

  cites [66] Farmakiotis, D., Tarrand, J. J. & Kontoyiannis, D. P. Drug-resistant Candida glabrata infection in cancer patients. Emerg. Infect. Dis. 20, 1833–1840 (2014). source

In the paper

“tolerant cell growth is slower and more time-dependent than resistant cell growth, and is less dependent on drug concentration9.”

What the sources say

• Partly supported

  The Results describe tolerant growth at supra-MIC fluconazole concentrations becoming evident at 48 hours while MIC remains unchanged, supporting a time-dependent distinction from resistance. Subpopulation growth dynamics reports delayed colony appearance with drug except in a resistant strain, but does not establish a general slower growth rate for tolerant versus resistant cells. The passages do not establish that tolerant growth is less dependent on drug concentration than resistant growth. (LLM, conf=0.82)

  cites [9] Rosenberg, A. et al. Antifungal tolerance is a subpopulation effect distinct from resistance and is associated with persistent candidemia. Nat. Commun. 9, 2470 (2018). This article provides a quantitative characterization of fluconazole tolerance in C. albicans, distinguishing it from resistance and highlighting its phenotypic heterogeneity and association with subpopulation growth, and sensitivity to adjuvant drugs. sourceExperimental — accuracy not yet measured

In the paper

“Furthermore, intracellular drug concentrations vary among cells within a given isolate, with the more tolerant isolates (those that grow slowly) having a larger population of cells with moderate amounts of drug per cell.”

What the sources say

• Supported

  The “Decreased intracellular drug levels underlie increased tolerance” section reports variation in drug levels among cells and a positive correlation between tolerance (FoG) and the proportion of cells with mid-level intracellular FLC-Cy5 (Fig. 3d–e). The “No adjuvant” section describes tolerant cells as growing slowly in the presence of FLC. Page numbers are not provided in our copy. (LLM, conf=0.94)

  cites [9] Rosenberg, A. et al. Antifungal tolerance is a subpopulation effect distinct from resistance and is associated with persistent candidemia. Nat. Commun. 9, 2470 (2018). This article provides a quantitative characterization of fluconazole tolerance in C. albicans, distinguishing it from resistance and highlighting its phenotypic heterogeneity and association with subpopulation growth, and sensitivity to adjuvant drugs. source

In the paper

“In Saccharomyces cerevisiae several genes involved in retrograde trafficking modulate tolerance and/or trailing growth, including VPS2127,51, VPS15 and VPS5194; Rim101 may influence tolerance via its ability to regulate the transcription of key components of the vacuolar trafficking pathway95.”

What the sources say

• ?Not checked — no full text of the sourcecites [27] Sanglard, D., Ischer, F., Marchetti, O., Entenza, J. & Bille, J. Calcineurin A of Candida albicans: involvement in antifungal tolerance, cell morphogenesis and virulence. Mol. Microbiol. 48, 959–976 (2003). source
• ?Could not verify

  Split into 2 atoms — 0 confirmed, 0 partially supported, 0 disputed, 0 misattributed, 2 unverifiable. Expand the claim to see per-atom verdicts.

  cites [51] Selmecki, A. M., Dulmage, K., Cowen, L. E., Anderson, J. B. & Berman, J. Acquisition of aneuploidy provides increased fitness during the evolution of antifungal drug resistance. PLoS Genet. 5, e1000705 (2009). sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [94] Roemer, T. & Krysan, D. J. Antifungal drug development: challenges, unmet clinical needs, and new approaches. Cold Spring Harb. Perspect. Med. 4, a019703 (2014). source
• ?Not checked — no full text of the sourcecites [95] Cornet, M. et al. Deletions of endocytic components VPS28 and VPS32 affect growth at alkaline pH and virulence through both RIM101-dependent and RIM101-independent pathways in Candida albicans. Infect. Immun. 73, 7977–7987 (2005). source

In the paper

“In part, this argument is based on the observation that inhibition of Hsp90 in the presence of fluconazole not only eliminates tolerance9 but also renders fluconazole fungicidal87.”

What the sources say

• Supported

  The ‘Adjuvant FLC combinations clear tolerance’ section reports that geldanamycin and radicicol inhibit Hsp90 and that fluconazole–adjuvant combinations cleared tolerance in the tested isolates. Figure 4 and its accompanying text also report that the tested combinations rendered fluconazole cidal, although the citing sentence attaches a separate citation to that point. (LLM, conf=0.93)

  cites [9] Rosenberg, A. et al. Antifungal tolerance is a subpopulation effect distinct from resistance and is associated with persistent candidemia. Nat. Commun. 9, 2470 (2018). This article provides a quantitative characterization of fluconazole tolerance in C. albicans, distinguishing it from resistance and highlighting its phenotypic heterogeneity and association with subpopulation growth, and sensitivity to adjuvant drugs. source
• Supported

  The Results section, “Inhibition of Hsp90 Function Converts the Fungistatic Activity of FL into a Fungicidal Combination,” reports that fluconazole (FL) combined with Hsp90 inhibition dramatically reduced viability in a C. albicans clinical isolate. Citation 87 is attached to the fungicidal claim; the separate tolerance claim is attributed to citation 9. (LLM, conf=0.94)

  cites [87] Cowen, L. E. et al. Harnessing Hsp90 function as a powerful, broadly effective therapeutic strategy for fungal infectious disease. Proc. Natl Acad. Sci. USA 106, 2818–2823 (2009). source

In the paper

“However, a more nuanced understanding of the fungal response to drugs may help explain the poor outcomes for infections caused by apparently susceptible isolates (that is, isolates that have a susceptible MIC at 24h, the standard endpoint for MIC measurements for Candida species).”

In the paper

“Resistant strains have MICs above the breakpoint and are more likely to cause a therapeutic failure than susceptible strains with MICs below the breakpoint.”

In the paper

“In the same isogenic population, a second subpopulation of cells does not grow in the drug or its extremely slow growth is not detectable following 48 h in the drug.”

In the paper

“Thus, one antifungal drug class becoming ineffective in treating a fungal infection owing to resistance reduces the therapeutic options by at least 33%, and frequently by 50% because azoles and echinocandins are not active against all fungi.”

In the paper

“Noteworthy, tolerant or trailing cells, when re-tested, have a similar MIC and a similar slow/partial growth in the presence of drugs at concentrations above the MIC (Fig. 1A).”

In the paper

“Although resistance is emerging in non-Candida species such as Aspergillus spp.,29 the general molecular mechanisms of resistance are conserved; therefore, we will focus primarily on Candida spp., the most prevalent species and the most common cause of both life-threatening invasive disease and clinically important mucosal diseases, such as vulvovaginal candidiasis, thrush and esophagitis.”

In the paper

“Furthermore, because of the overlapping functions of different efflux pumps, mutations such as loss-of-function of a single gene encoding an efflux pump, or gain-of-function of less efficient efflux pumps, have only modest effects on bona fide resistance and the most dramatic effects are from overexpression combined with homozygosis (loss of heterozygosity) of hyperactive transcription factor alle”

What the sources say

• ?Not checked — no full text of the sourcecites [33] Sasse, C. et al. The stepwise acquisition of fluconazole resistance mutations causes a gradual loss of fitness in Candida albicans. Mol. Microbiol. 86, 539–556 (2012). This article shows that when a strain accumulates multiple resistance mutations that affect different transcription factors, the effects are independent and additive. In addition, these effects, generated by engineered deletion mutations, are associated with reduced fitness in the absence of drug stress. As many resistant isolates do not have obvious fitness defects, it is assumed that they must have acquired compensatory mechan source
• ?Not checked — no full text of the sourcecites [37] Xiang, M. J. et al. Erg11 mutations associated with azole resistance in clinical isolates of Candida albicans. FEMS Yeast Res. 13, 386–393 (2013). source

In the paper

“Trailing growth is often estimated as the percent of growth at different drug concentrations relative to growth in the absence of drug16, a measure similar to the ‘supra-MIC growth’ (SMG) parameter used to measure tolerance (Fig. 1B).”

What the sources say

• ?Not checked — no full text of the sourcecites [16] Marcos-Zambrano, L. J., Escribano, P., Sanchez-Carrillo, C., Bouza, E. & Guinea, J. Scope and frequency of fluconazole trailing assessed using EUCAST in invasive Candida spp. isolates. Med. Mycol. 54, 733–739 (2016). source

In the paper

“Clinical breakpoints provide guidance regarding the likelihood that a given isolate will respond to therapy.”

In the paper

“Increased ERG11 expression is also seen in intrinsically resistant non-C. albicans species; however, the underlying mechanism is unknown.”

In the paper

“Specifically, many published reports refer to resistance as an increase in the MIC relative to a reference strain, particularly in the setting of work focused on elucidating the mechanisms of resistance.”

In the paper

“The response to hydroxyurea was shown to be dependent on two of the 1087 different genes located on chromosome 2: RNR1 and RNR21; the genes responsible for survival in the presence of caspofungin are distinct from these RNR genes and have not yet been identified47.”

What the sources say

• ?Not checked — no full text of the sourcecites [47] Yang, F., Kravets, A., Bethlendy, G., Welle, S. & Rustchenko, E. Chromosome 5 monosomy of Candida albicans controls susceptibility to various toxic agents, including major antifungals. Antimicrob. Agents Chemother. 57, 5026–5036 (2013). source

In the paper

“The degree of tolerance varies across different isolates, presumably owing to the intrinsic allele diversity of each isolate.”

In the paper

“Recent guidelines of the Infectious Disease Society of America recommend that an echinocandin, rather than azoles, be used as initial therapy for most invasive Candida spp. infections64.”

What the sources say

• ?Not checked — no full text of the sourcecites [64] Forche, A., Magee, P. T., Selmecki, A., Berman, J. & May, G. Evolution in Candida albicans populations during a single passage through a mouse host. Genetics 182, 799–811 (2009). source

In the paper

“This is tolerance, rather than resistance, because the MIC remained susceptible and the increased growth was detected after incubation for more than the 24 h in standard MIC assays.”

In the paper

“By contrast, for a single isolate, the phenotypic heterogeneity that drives some cells to grow slowly, and others to arrest growth, must be due to physiological or metabolic shifts that differ between isogenic cells in the population.”

In the paper

“Thus, tolerance is likely to be due to physiological responses that emerge heterogeneously among the cell population, where the proportion of cells exhibiting such responses is a function of the genetic potential of the specific isolate.”

In the paper

“By contrast, tolerance is a feature of susceptible (non-resistant) isolates that relies upon several central stress response pathways; it is a consequence of phenotypic heterogeneity, in which some cells in the population grow, albeit slowly, in drug.”

In the paper

“Nonetheless, because a highly tolerant strain will divide more frequently in the presence of fluconazole than a strain with low tolerance levels, it will also have a higher population size and a higher likelihood of acquiring new mutations.”

In the paper

“We posit that inter-isolate heterogeneity in tolerance is a composite phenotype that emerges from variations at multiple loci; that is, different stress response pathways probably contribute to tolerance to a different degree in different isolates.”

In the paper

“Transcription factors can regulate multiple targets, and therefore the downstream effects of mutations in those transcription factors on resistance and tolerance could be independent of one another.”

In the paper

“Resistance is due to genetic changes that directly affect either the drug target and/or intracellular drug concentrations and cause a heritable effect on the entire population of cells in a given isolate.”

In the paper

“Cell-to-cell phenotypic heterogeneity occurs at a frequency that is far too high (10-90% of cells) to be due to the genetic acquisition of mutations, implying that it is due to non-genetic differences between the cells.”

In the paper

“Thus, tolerance has a genetic component that varies between isolates, and a non-genetic component that is influenced by growth conditions and cell physiology.”

In the paper

“It appears that most, or all, of these fluconazole-associated stress response pathways affect tolerance, because inhibiting these pathways does not affect MIC levels (Box 5).”

In the paper

“Thus, no colonies grow when fluconazole and an Hsp90 inhibitor are combined, because dead cells cannot evolve.”

In the paper

“Thus, although resistance and tolerance are different (as described above), they may share the same processes (albeit to different degrees) to promote growth in the presence of antifungal drugs.”