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Czajka KM, Venkataraman K, Brabant-Kirwan D, Santi SA, Verschoor C, Appanna VD, Singh R, Saunders DP, Tharmalingam S. Molecular Mechanisms Associated with Antifungal Resistance in Pathogenic Candida Species. Cells 2023; 12:2655. [PMID: 37998390 PMCID: PMC10670235 DOI: 10.3390/cells12222655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 11/14/2023] [Accepted: 11/17/2023] [Indexed: 11/25/2023] Open
Abstract
Candidiasis is a highly pervasive infection posing major health risks, especially for immunocompromised populations. Pathogenic Candida species have evolved intrinsic and acquired resistance to a variety of antifungal medications. The primary goal of this literature review is to summarize the molecular mechanisms associated with antifungal resistance in Candida species. Resistance can be conferred via gain-of-function mutations in target pathway genes or their transcriptional regulators. Therefore, an overview of the known gene mutations is presented for the following antifungals: azoles (fluconazole, voriconazole, posaconazole and itraconazole), echinocandins (caspofungin, anidulafungin and micafungin), polyenes (amphotericin B and nystatin) and 5-fluorocytosine (5-FC). The following mutation hot spots were identified: (1) ergosterol biosynthesis pathway mutations (ERG11 and UPC2), resulting in azole resistance; (2) overexpression of the efflux pumps, promoting azole resistance (transcription factor genes: tac1 and mrr1; transporter genes: CDR1, CDR2, MDR1, PDR16 and SNQ2); (3) cell wall biosynthesis mutations (FKS1, FKS2 and PDR1), conferring resistance to echinocandins; (4) mutations of nucleic acid synthesis/repair genes (FCY1, FCY2 and FUR1), resulting in 5-FC resistance; and (5) biofilm production, promoting general antifungal resistance. This review also provides a summary of standardized inhibitory breakpoints obtained from international guidelines for prominent Candida species. Notably, N. glabrata, P. kudriavzevii and C. auris demonstrate fluconazole resistance.
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Affiliation(s)
- Karolina M. Czajka
- Medical Sciences Division, NOSM University, 935 Ramsey Lake Rd., Sudbury, ON P3E 2C6, Canada; (K.M.C.); (K.V.); (C.V.); (R.S.); (D.P.S.)
| | - Krishnan Venkataraman
- Medical Sciences Division, NOSM University, 935 Ramsey Lake Rd., Sudbury, ON P3E 2C6, Canada; (K.M.C.); (K.V.); (C.V.); (R.S.); (D.P.S.)
- School of Natural Sciences, Laurentian University, Sudbury, ON P3E 2C6, Canada;
| | | | - Stacey A. Santi
- Health Sciences North Research Institute, Sudbury, ON P3E 2H2, Canada; (D.B.-K.); (S.A.S.)
| | - Chris Verschoor
- Medical Sciences Division, NOSM University, 935 Ramsey Lake Rd., Sudbury, ON P3E 2C6, Canada; (K.M.C.); (K.V.); (C.V.); (R.S.); (D.P.S.)
- School of Natural Sciences, Laurentian University, Sudbury, ON P3E 2C6, Canada;
- Health Sciences North Research Institute, Sudbury, ON P3E 2H2, Canada; (D.B.-K.); (S.A.S.)
| | - Vasu D. Appanna
- School of Natural Sciences, Laurentian University, Sudbury, ON P3E 2C6, Canada;
| | - Ravi Singh
- Medical Sciences Division, NOSM University, 935 Ramsey Lake Rd., Sudbury, ON P3E 2C6, Canada; (K.M.C.); (K.V.); (C.V.); (R.S.); (D.P.S.)
- Health Sciences North Research Institute, Sudbury, ON P3E 2H2, Canada; (D.B.-K.); (S.A.S.)
| | - Deborah P. Saunders
- Medical Sciences Division, NOSM University, 935 Ramsey Lake Rd., Sudbury, ON P3E 2C6, Canada; (K.M.C.); (K.V.); (C.V.); (R.S.); (D.P.S.)
- Health Sciences North Research Institute, Sudbury, ON P3E 2H2, Canada; (D.B.-K.); (S.A.S.)
| | - Sujeenthar Tharmalingam
- Medical Sciences Division, NOSM University, 935 Ramsey Lake Rd., Sudbury, ON P3E 2C6, Canada; (K.M.C.); (K.V.); (C.V.); (R.S.); (D.P.S.)
- School of Natural Sciences, Laurentian University, Sudbury, ON P3E 2C6, Canada;
- Health Sciences North Research Institute, Sudbury, ON P3E 2H2, Canada; (D.B.-K.); (S.A.S.)
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Tian Y, Zhuang Y, Chen Z, Mao Y, Zhang J, Lu R, Guo L. A gain-of-function mutation in PDR1 of Candida glabrata decreases EPA1 expression and attenuates adherence to epithelial cells through enhancing recruitment of the Mediator subunit Gal11A. Microbiol Res 2020; 239:126519. [PMID: 32563123 DOI: 10.1016/j.micres.2020.126519] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 02/26/2020] [Accepted: 05/23/2020] [Indexed: 12/28/2022]
Abstract
Genetic studies have revealed critical roles of transcription factor Pdr1 and the Mediator subunit Gal11A in regulating azole resistance in Candida glabrata. Recently, PDR1 gain-of-function (GOF) mutations have been shown to not only increase azole resistance but also enhance adherence during C. glabrata infection. However, mechanism of how Pdr1 regulates adherence, especially the implication of PDR1 GOF mutations in the regulation of the major adhesin gene EPA1, remains uncharacterized. Initially, we unexpectedly observed that expression of PDR1 harbouring GOF mutation G346D down-regulated EPA1 transcription and attenuated adherence to epithelial cells in different strain backgrounds. Given that PDR1 GOF mutations have been previously regarded as stimulators for adherence of this species, these findings prompted us to explore the regulation of EPA1 by wild-type Pdr1 and Pdr1 harbouring G346D mutation. Epitope tagged version of Pdr1 and Gal11A were utilized to determine the association of Pdr1 and Gal11A with EPA1 promoter. A combination of approaches including deletion, molecular, and biochemical assays showed that EPA1 is a direct target of Pdr1, and demonstrated for the first time that PDR1 G346D mutation decreases EPA1 expression and attenuates adherence to epithelial cells via enhancing recruitment of Gal11A. Taken together, our data propose a critical role of Gal11A in Pdr1-regulated EPA1 expression and adherence to epithelial cells, which could be utilized a novel therapeutic target for the treatment of hyper-adherent C. glabrata infection.
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Affiliation(s)
- Yuan Tian
- Department of Clinical Laboratory, Fudan University Shanghai Cancer Center, Shanghai, China; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.
| | - Yihui Zhuang
- Department of Clinical Laboratory, Fudan University Shanghai Cancer Center, Shanghai, China; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.
| | - Zhujun Chen
- Department of Clinical Laboratory, Fudan University Shanghai Cancer Center, Shanghai, China; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.
| | - Yinhe Mao
- Unit of Pathogenic Fungal Infection and Host Immunity, Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai 200031, China.
| | - Jing Zhang
- Department of Clinical Laboratory, Fudan University Shanghai Cancer Center, Shanghai, China; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.
| | - Renquan Lu
- Department of Clinical Laboratory, Fudan University Shanghai Cancer Center, Shanghai, China; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.
| | - Lin Guo
- Department of Clinical Laboratory, Fudan University Shanghai Cancer Center, Shanghai, China; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China.
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Gabaldón T, Gómez-Molero E, Bader O. Molecular Typing of Candida glabrata. Mycopathologia 2019; 185:755-764. [PMID: 31617105 DOI: 10.1007/s11046-019-00388-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 09/21/2019] [Indexed: 12/17/2022]
Abstract
The yeast Candida glabrata has emerged, second only to Candida albicans, to be one of the most frequently isolated fungi in clinical specimen from human. Its frequent resistance towards azole antifungal drugs and the high capacity to form biofilms on indwelling catheters of individual isolates render it an often difficult to treat pathogen. Hence, there is a notably increasing scientific and clinical interest in this species. This has led to the development of a variety of molecular tools for genetic modification, strain collections, and last but not least different approaches to analyse the population structure among isolates of different geographical and clinical contexts. Often, these are used to study correlations (or the absence thereof) with different pathogenicity, virulence, or drug resistance traits. Three molecular methods have been used to type within the C. glabrata population on a genetic level by multiple studies: multi-locus sequence typing, microsatellite length polymorphisms, and clustering of whole-genome sequencing data, and these are subject of this review.
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Affiliation(s)
- Toni Gabaldón
- Comparative Genomics Group, Life Science Programme, Barcelona Supercomputing Centre (BSC-CNS), Barcelona, Spain
- Institute of Research in Biomedicine (IRB), Barcelona, Spain
- Institució Catalana de Recerca I Estudis Avançats (ICREA), Barcelona, Spain
| | - Emilia Gómez-Molero
- Institute for Medical Microbiology, University Medical Center Göttingen, Kreuzbergring 57, 37075, Göttingen, Germany
| | - Oliver Bader
- Institute for Medical Microbiology, University Medical Center Göttingen, Kreuzbergring 57, 37075, Göttingen, Germany.
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Novel Zinc-Attenuating Compounds as Potent Broad-Spectrum Antifungal Agents with In Vitro and In Vivo Efficacy. Antimicrob Agents Chemother 2018; 62:AAC.02024-17. [PMID: 29439980 PMCID: PMC5923171 DOI: 10.1128/aac.02024-17] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 02/04/2018] [Indexed: 12/23/2022] Open
Abstract
An increase in the incidence of rare but hard-to-treat invasive fungal pathogens as well as resistance to the currently available antifungal drugs calls for new broad-spectrum antifungals with a novel mechanism of action. Here we report the identification and characterization of two novel zinc-attenuating compounds, ZAC307 and ZAC989, which exhibit broad-spectrum in vitro antifungal activity and in vivo efficacy in a fungal kidney burden candidiasis model. The compounds were identified serendipitously as part of a drug discovery process aimed at finding novel inhibitors of the fungal plasma membrane proton ATPase Pma1. Based on their structure, we hypothesized that they might act as zinc chelators. Indeed, both fluorescence-based affinity determination and potentiometric assays revealed these compounds, subsequently termed zinc-attenuating compounds (ZACs), to have strong affinity for zinc, and their growth inhibitory effects on Candida albicans and Aspergillus fumigatus could be inactivated by the addition of exogenous zinc to fungal growth media. We determined the ZACs to be fungistatic, with a low propensity for resistance development. Gene expression analysis suggested that the ZACs interfere negatively with the expression of genes encoding the major components of the A. fumigatus zinc uptake system, thus supporting perturbance of zinc homeostasis as the likely mode of action. With demonstrated in vitro and in vivo antifungal activity, low propensity for resistance development, and a novel mode of action, the ZACs represent a promising new class of antifungal compounds, and their advancement in a drug development program is therefore warranted.
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Bublitz M, Kjellerup L, Cohrt KO, Gordon S, Mortensen AL, Clausen JD, Pallin TD, Hansen JB, Fuglsang AT, Dalby-Brown W, Winther AML. Tetrahydrocarbazoles are a novel class of potent P-type ATPase inhibitors with antifungal activity. PLoS One 2018; 13:e0188620. [PMID: 29293507 PMCID: PMC5749684 DOI: 10.1371/journal.pone.0188620] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 11/10/2017] [Indexed: 11/19/2022] Open
Abstract
We have identified a series of tetrahydrocarbazoles as novel P-type ATPase inhibitors. Using a set of rationally designed analogues, we have analyzed their structure-activity relationship using functional assays, crystallographic data and computational modeling. We found that tetrahydrocarbazoles inhibit adenosine triphosphate (ATP) hydrolysis of the fungal H+-ATPase, depolarize the fungal plasma membrane and exhibit broad-spectrum antifungal activity. Comparative inhibition studies indicate that many tetrahydrocarbazoles also inhibit the mammalian Ca2+-ATPase (SERCA) and Na+,K+-ATPase with an even higher potency than Pma1. We have located the binding site for this compound class by crystallographic structure determination of a SERCA-tetrahydrocarbazole complex to 3.0 Å resolution, finding that the compound binds to a region above the ion inlet channel of the ATPase. A homology model of the Candida albicans H+-ATPase based on this crystal structure, indicates that the compounds could bind to the same pocket and identifies pocket extensions that could be exploited for selectivity enhancement. The results of this study will aid further optimization towards selective H+-ATPase inhibitors as a new class of antifungal agents.
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Affiliation(s)
- Maike Bublitz
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Lasse Kjellerup
- Pcovery, Copenhagen N, Denmark
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | | | | | | | | | | | | | - Anja Thoe Fuglsang
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
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Clausen JD, Kjellerup L, Cohrt KO, Hansen JB, Dalby-Brown W, Winther AML. Elucidation of antimicrobial activity and mechanism of action by N-substituted carbazole derivatives. Bioorg Med Chem Lett 2017; 27:4564-4570. [PMID: 28893470 PMCID: PMC5609566 DOI: 10.1016/j.bmcl.2017.08.067] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 08/20/2017] [Accepted: 08/25/2017] [Indexed: 11/15/2022]
Abstract
Compounds belonging to a carbazole series have been identified as potent fungal plasma membrane proton adenosine triphophatase (H+-ATPase) inhibitors with a broad spectrum of antifungal activity. The carbazole compounds inhibit the adenosine triphosphate (ATP) hydrolysis activity of the essential fungal H+-ATPase, thereby functionally inhibiting the extrusion of protons and extracellular acidification, processes that are responsible for maintaining high plasma membrane potential. The compound class binds to and inhibits the H+-ATPase within minutes, leading to fungal death after 1-3h of compound exposure in vitro. The tested compounds are not selective for the fungal H+-ATPase, exhibiting an overlap of inhibitory activity with the mammalian protein family of P-type ATPases; the sarco(endo)plasmic reticulum calcium ATPase (Ca2+-ATPase) and the sodium potassium ATPase (Na+,K+-ATPase). The ion transport in the P-type ATPases is energized by the conversion of ATP to adenosine diphosphate (ADP) and phosphate and a general inhibitory mechanism mediated by the carbazole derivative could therefore be blocking of the active site. However, biochemical studies show that increased concentrations of ATP do not change the inhibitory activity of the carbazoles suggesting they act as allosteric inhibitors. Furthermore decreased levels of intracellular ATP would suggest that the compounds inhibit the H+-ATPase indirectly, but Candida albicans cells exposed to potent H+-ATPase-inhibitory carbazoles result in increased levels of intracellular ATP, indicating direct inhibition of H+-ATPase.
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Affiliation(s)
| | - Lasse Kjellerup
- Pcovery ApS, Ole Maaløes Vej 3, 2200 Copenhagen N, Denmark; Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg, Denmark
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Heteroresistance to Fluconazole Is a Continuously Distributed Phenotype among Candida glabrata Clinical Strains Associated with In Vivo Persistence. mBio 2016; 7:mBio.00655-16. [PMID: 27486188 PMCID: PMC4981708 DOI: 10.1128/mbio.00655-16] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Candida glabrata causes persistent infections in patients treated with fluconazole and often acquires resistance following exposure to the drug. Here we found that clinical strains of C. glabrata exhibit cell-to-cell variation in drug response (heteroresistance). We used population analysis profiling (PAP) to assess fluconazole heteroresistance (FLCHR) and to ask if it is a binary trait or a continuous phenotype. Thirty (57.6%) of 52 fluconazole-sensitive clinical C. glabrata isolates met accepted dichotomous criteria for FLCHR. However, quantitative grading of FLCHR by using the area under the PAP curve (AUC) revealed a continuous distribution across a wide range of values, suggesting that all isolates exhibit some degree of heteroresistance. The AUC correlated with rhodamine 6G efflux and was associated with upregulation of the CDR1 and PDH1 genes, encoding ATP-binding cassette (ABC) transmembrane transporters, implying that HetR populations exhibit higher levels of drug efflux. Highly FLCHRC. glabrata was recovered more frequently than nonheteroresistant C. glabrata from hematogenously infected immunocompetent mice following treatment with high-dose fluconazole (45.8% versus 15%, P = 0.029). Phylogenetic analysis revealed some phenotypic clustering but also variations in FLCHR within clonal groups, suggesting both genetic and epigenetic determinants of heteroresistance. Collectively, these results establish heteroresistance to fluconazole as a graded phenotype associated with ABC transporter upregulation and fluconazole efflux. Heteroresistance may explain the propensity of C. glabrata for persistent infection and the emergence of breakthrough resistance to fluconazole. Heteroresistance refers to variability in the response to a drug within a clonal cell population. This phenomenon may have crucial importance for the way we look at antimicrobial resistance, as heteroresistant strains are not detected by standard laboratory susceptibility testing and may be associated with failure of antimicrobial therapy. We describe for the first time heteroresistance to fluconazole in C. glabrata, a finding that may explain the propensity of this pathogen to acquire resistance following exposure to fluconazole and to persist despite treatment. We found that, rather than being a binary all-or-none trait, heteroresistance was a continuously distributed phenotype associated with increased expression of genes that encode energy-dependent drug efflux transporters. Moreover, we show that heteroresistance is associated with failure of fluconazole to clear infection with C. glabrata. Together, these findings provide an empirical framework for determining and quantifying heteroresistance in C. glabrata.
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Katiyar S, Shiffrin E, Shelton C, Healey K, Vermitsky JP, Edlind T. Evaluation of Polymorphic Locus Sequence Typing for Candida glabrata Epidemiology. J Clin Microbiol 2016; 54:1042-50. [PMID: 26842706 PMCID: PMC4809956 DOI: 10.1128/jcm.03106-15] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 01/29/2016] [Indexed: 11/20/2022] Open
Abstract
The opportunistic yeast Candida glabratais increasingly refractory to antifungal treatment or prophylaxis and relatedly is increasingly implicated in health care-associated infections. To elucidate the epidemiology of these infections, strain typing is required. Sequence-based typing provides multiple advantages over length-based methods, such as pulsed-field gel electrophoresis (PFGE); however, conventional multilocus sequence typing (targeting 6 conserved loci) and whole-genome sequencing are impractical for routine use. A commercial sequence-based typing service for C. glabratathat targets polymorphic tandem repeat-containing loci has recently been developed. These CgMT-J and CgMT-M services were evaluated with 56 epidemiologically unrelated isolates, 4 to 7 fluconazole-susceptible or fluconazole-resistant isolates from each of 5 center A patients, 5 matched pairs of fluconazole-susceptible/resistant isolates from center B patients, and 7 isolates from a center C patient who responded to then failed caspofungin therapy. CgMT-J and CgMT-M generated congruent results, resolving isolates into 24 and 20 alleles, respectively. Isolates from all but one of the center A patients shared the same otherwise rare alleles, suggesting nosocomial transmission. Unexpectedly, Pdr1 sequencing showed that resistance arose independently in each patient. Similarly, most isolates from center B also clustered together; however, this may reflect a dominant clone since their alleles were shared by multiple unrelated isolates. Although distinguishable by their echinocandin susceptibilities, all isolates from the center C patient shared alleles, in agreement with the previously reported relatedness of these isolates based on PFGE. Finally, we show how phylogenetic clusters can be used to provide surrogate parents to analyze the mutational basis for antifungal resistance.
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Affiliation(s)
- Santosh Katiyar
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Eric Shiffrin
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Celeste Shelton
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Kelley Healey
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - John-Paul Vermitsky
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Tom Edlind
- MicrobiType LLC, Plymouth Meeting, Pennsylvania, USA
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Silva DBDS, Rodrigues LMC, Almeida AAD, Oliveira KMPD, Grisolia AB. Novel point mutations in the ERG11 gene in clinical isolates of azole resistant Candida species. Mem Inst Oswaldo Cruz 2016; 111:192-9. [PMID: 26982177 PMCID: PMC4804502 DOI: 10.1590/0074-02760150400] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 02/15/2016] [Indexed: 11/22/2022] Open
Abstract
The azoles are the class of medications most commonly used to fight infections caused
by Candida sp. Typically, resistance can be attributed to mutations
in ERG11 gene (CYP51) which encodes the cytochrome P450
14α-demethylase, the primary target for the activity of azoles. The objective of this
study was to identify mutations in the coding region of theERG11
gene in clinical isolates of Candidaspecies known to be resistant to
azoles. We identified three new synonymous mutations in the ERG11
gene in the isolates of Candida glabrata (C108G, C423T and A1581G)
and two new nonsynonymous mutations in the isolates of Candida
krusei - A497C (Y166S) and G1570A (G524R). The functional consequence of
these nonsynonymous mutations was predicted using evolutionary conservation scores.
The G524R mutation did not have effect on 14α-demethylase functionality, while the
Y166S mutation was found to affect the enzyme. This observation suggests a possible
link between the mutation and dose-dependent sensitivity to voriconazole in the
clinical isolate of C. krusei. Although the presence of the Y166S in
phenotype of reduced azole sensitivity observed in isolate C.
kruseidemands investigation, it might contribute to the search of new
therapeutic agents against resistant Candida isolates.
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Szweda P, Gucwa K, Romanowska E, Dzierz Anowska-Fangrat K, Naumiuk Ł, Brillowska-Da Browska A, Wojciechowska-Koszko I, Milewski S. Mechanisms of azole resistance among clinical isolates of Candida glabrata in Poland. J Med Microbiol 2015; 64:610-619. [PMID: 25818698 DOI: 10.1099/jmm.0.000062] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Candida glabrata is currently ranked as the second most frequently isolated aetiological agent of human fungal infections, next only to Candida albicans. In comparison with C. albicans, C. glabrata shows lower susceptibility to azoles, the most common agents used in treatment of fungal infections. Interestingly, the mechanisms of resistance to azole agents in C. albicans have been much better investigated than those in C. glabrata. The aim of the presented study was to determine the mechanisms of resistance to azoles in 81 C. glabrata clinical isolates from three different hospitals in Poland. The investigation was carried out with a Sensititre Yeast One test and revealed that 18 strains were resistant to fluconazole, and 15 were cross-resistant to all other azoles tested (voriconazole, posaconazole and itraconazole). One isolate resistant to fluconazole was cross-resistant to voriconazole, and resistance to voriconazole only was observed in six other isolates. All strains were found to be susceptible to echinocandins and amphotericin B, and five were classified as resistant to 5-fluorocytosine. The sequence of the ERG11 gene encoding lanosterol 14-α demethylase (the molecular target of azoles) of 41 isolates, including all strains resistant to fluconazole and three resistant only to voriconazole, was determined, and no amino acid substitutions were found. Real-time PCR studies revealed that 13 of 15 azole-resistant strains showed upregulation of the CDR1 gene encoding the efflux pump. No upregulation of expression of the CDR2 or ERG11 gene was observed.
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Affiliation(s)
- Piotr Szweda
- Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Gdansk University of Technology, Gabriela Narutowicza Str. 11/12, 80-233 Gdansk, Poland
| | - Katarzyna Gucwa
- Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Gdansk University of Technology, Gabriela Narutowicza Str. 11/12, 80-233 Gdansk, Poland
| | - Ewa Romanowska
- Department of Clinical Microbiology and Immunology, The Children's Memorial Health Institute, Aleja Dzieci Polskich 20, 04-730 Warsaw, Poland
| | - Katarzyna Dzierz Anowska-Fangrat
- Department of Clinical Microbiology and Immunology, The Children's Memorial Health Institute, Aleja Dzieci Polskich 20, 04-730 Warsaw, Poland
| | - Łukasz Naumiuk
- Department of Clinical Microbiology, Hospital of the Medical University of Gdansk, Debinki Str. 7, 80-954 Gdansk, Poland
| | - Anna Brillowska-Da Browska
- Department of Microbiology, Faculty of Chemistry, Gdansk University of Technology, Narutowicza Str. 11/12, 80-233 Gdansk, Poland
| | - Iwona Wojciechowska-Koszko
- Department of Microbiology and Immunology, Pomeranian Medical University, Powstanców Wielkopolskich 72, 70-111 Szczecin, Poland
| | - Sławomir Milewski
- Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Gdansk University of Technology, Gabriela Narutowicza Str. 11/12, 80-233 Gdansk, Poland
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Jandric Z, Gregori C, Klopf E, Radolf M, Schüller C. Sorbic acid stress activates the Candida glabrata high osmolarity glycerol MAP kinase pathway. Front Microbiol 2013; 4:350. [PMID: 24324463 PMCID: PMC3840799 DOI: 10.3389/fmicb.2013.00350] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 11/04/2013] [Indexed: 12/27/2022] Open
Abstract
Weak organic acids such as sorbic acid are important food preservatives and powerful fungistatic agents. These compounds accumulate in the cytosol and disturb the cellular pH and energy homeostasis. Candida glabrata is in many aspects similar to Saccharomyces cerevisiae. However, with regard to confrontation to sorbic acid, two of the principal response pathways behave differently in C. glabrata. In yeast, sorbic acid stress causes activation of many genes via the transcription factors Msn2 and Msn4. The C. glabrata homologs CgMsn2 and CgMsn4 are apparently not activated by sorbic acid. In contrast, in C. glabrata the high osmolarity glycerol (HOG) pathway is activated by sorbic acid. Here we show that the MAP kinase of the HOG pathway, CgHog1, becomes phosphorylated and has a function for weak acid stress resistance. Transcript profiling of weak acid treated C. glabrata cells suggests a broad and very similar response pattern of cells lacking CgHog1 compared to wild type which is over lapping with but distinct from S. cerevisiae. The PDR12 gene was the highest induced gene in both species and it required CgHog1 for full expression. Our results support flexibility of the response cues for general stress signaling pathways, even between closely related yeasts, and functional extension of a specific response pathway.
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Affiliation(s)
- Zeljkica Jandric
- Department of Applied Genetics and Cell Biology (DAGZ), University of Natural Resources and Life Sciences Vienna, Austria
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Oliveira Carvalho V, Okay TS, Melhem MSC, Walderez Szeszs M, del Negro GMB. The new mutation L321F in Candida albicans ERG11 gene may be associated with fluconazole resistance. Rev Iberoam Micol 2013; 30:209-12. [PMID: 23402828 DOI: 10.1016/j.riam.2013.01.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 12/13/2012] [Accepted: 01/30/2013] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND For many years fluconazole has been commonly used to treat Candida infections. However, the indiscriminate use of this antimycotic therapy has favored the emergence of resistant isolates. Mutations in the ERG11 gene have been described as one of the primary mechanisms of resistance in Candida species. AIMS In this study we investigated missense mutations in ERG11 genes of Candida albicans, Candida glabrata and Candida tropicalis isolates previously evaluated by susceptibility testing to fluconazole. METHODS Screening for these mutations was performed on 19 Candida clinical isolates (eight C. albicans, five C. glabrata and six C. tropicalis) resistant and susceptible to fluconazole. The ERG11 gene was amplified by PCR with specific primers for each Candida species and analyzed by automated sequencing. RESULTS We identified 14 different missense mutations, five of which had not been described previously. Among them, a new mutation L321F was identified in a fluconazole resistant C. albicans isolate and it was analyzed by a theoretical three-dimensional structure of the ERG11p. CONCLUSION The L321F mutation in C. albicans ERG11 gene may be associated with fluconazole resistance.
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Affiliation(s)
- Vagner Oliveira Carvalho
- Laboratory of Medical Mycology (LIM-53)-Clinical Dermatology Division, Hospital das Clínicas da FMUSP e Instituto de Medicina Tropical de São Paulo, Universidade de São Paulo, São Paulo, State of São Paulo, Brazil.
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Farahyar S, Zaini F, Kordbacheh P, Rezaie S, Safara M, Raoofian R, Heidari M. Overexpression of aldo-keto-reductase in azole-resistant clinical isolates of Candida glabrata determined by cDNA-AFLP. ACTA ACUST UNITED AC 2013; 21:1. [PMID: 23351326 PMCID: PMC3556022 DOI: 10.1186/2008-2231-21-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2012] [Accepted: 12/29/2012] [Indexed: 01/05/2023]
Abstract
Background Candida glabrata causes significant medical problems in immunocompromised patients. Many strains of this yeast are intrinsically resistant to azole antifungal agents, and treatment is problematic, leading to high morbidity and mortality rates in immunosuppressed individuals. The primary goal of this study was to investigate the genes involved in the drug resistance of clinical isolates of C. glabrata. Methods The clinical isolates of C. glabrata were collected in an epidemiological survey of candidal infection in immunocompromised patients and consisted of four fluconazole and itraconazole resistant isolates, two fluconazole and itraconazole sensitive isolates, and C. glabrata CBS 138 as reference strain. Antifungal susceptibility patterns of the organisms were determined beforehand by the Clinical and Laboratory Standards Institute (CLSI). The potential gene(s) implicated in antifungal resistance were investigated using complementary DNA- Amplified Fragment Length Polymorphism (cDNA-AFLP). Semi-quantitative RT-PCR was carried out to evaluate the expression of gene(s) in resistant isolates as compared to sensitive and reference strains. Results and conclusions The aldo-keto-reductase superfamily (AKR gene) was upregulated in the resistant clinical isolates as assessed by cDNA-AFLP. Semi-quantitative RT-PCR revealed AKR mRNA expression approximately twice that seen in the sensitive isolates. Overexpression of the AKR gene was associated with increased fluconazole and itraconazole resistance in C. glabrata. The data suggest that upregulation of the AKR gene might give a new insight into the mechanism of azole resistance.
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Affiliation(s)
- Shirin Farahyar
- Department of Medical Mycology and Parasitology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
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Microsatellite-based genotyping of Candida parapsilosis sensu stricto isolates reveals dominance and persistence of a particular epidemiological clone among neonatal intensive care unit patients. INFECTION GENETICS AND EVOLUTION 2012; 13:105-8. [PMID: 23022715 DOI: 10.1016/j.meegid.2012.09.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 09/13/2012] [Accepted: 09/14/2012] [Indexed: 11/20/2022]
Abstract
In this study, using multilocus microsatellite analysis, we report the genetic characterization of 27 Candida parapsilosis isolates recovered in two different periods of time (2007-2009 and 2011-2012) from infants hospitalized in the neonatal intensive care unit of a hospital in Messina, Italy. The results revealed the persistence and dominance of a particular infectious genotype among NICU patients and highlight the power of the used microsatellite markers in clarifying epidemiologic associations, detect micro-evolutionary variations and facilitating the recognition of outbreaks.
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Diagnosis of Antifungal Drug Resistance Mechanisms in Fungal Pathogens: Transcriptional Gene Regulation. CURRENT FUNGAL INFECTION REPORTS 2011. [DOI: 10.1007/s12281-011-0055-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Oxidative stress response and virulence factors in Candida glabrata clinical isolates. Folia Microbiol (Praha) 2011; 56:116-21. [PMID: 21416384 DOI: 10.1007/s12223-011-0016-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Accepted: 01/17/2011] [Indexed: 01/19/2023]
Abstract
We determined the susceptibility to oxidative stress and assessed the four virulence factors of the 38 Candida glabrata clinical isolates originating from two teaching hospitals in Slovakia. All the isolates were susceptible to hydrogen peroxide, diamide, and 7-chlorotetrazolo[5,1-c]benzo[1,2,4]triazine (CTBT) inducing an increased formation of reactive oxygen species in fungal cells. The mean relative cell surface hydrophobicity (CSH) of isolates was 21.9, ranging from 1.92 to 56.96. All isolates showed biofilm formation. A high biofilm formation was observed among 60.5% of isolates. Positive correlations were observed between biofilm formation and moderate values of CSHs. The 76.3% and 84.2% of isolates displayed varying degrees of proteinase and phospholipase activity, respectively. These results demonstrate a differential distribution of factors contributing to virulence of C. glabrata clinical isolates and point to their significance in pathogenesis that would be targeted by novel antifungals.
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Ferrari S, Sanguinetti M, Torelli R, Posteraro B, Sanglard D. Contribution of CgPDR1-regulated genes in enhanced virulence of azole-resistant Candida glabrata. PLoS One 2011; 6:e17589. [PMID: 21408004 PMCID: PMC3052359 DOI: 10.1371/journal.pone.0017589] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Accepted: 01/27/2011] [Indexed: 12/20/2022] Open
Abstract
In Candida glabrata, the transcription factor CgPdr1 is involved
in resistance to azole antifungals via upregulation of ATP binding cassette
(ABC)-transporter genes including at least CgCDR1,
CgCDR2 and CgSNQ2. A high diversity of GOF
(gain-of-function) mutations in CgPDR1 exists for the
upregulation of ABC-transporters. These mutations enhance C.
glabrata virulence in animal models, thus indicating that
CgPDR1 might regulate the expression of yet unidentified
virulence factors. We hypothesized that CgPdr1-dependent virulence factor(s)
should be commonly regulated by all GOF mutations in CgPDR1. As
deduced from transcript profiling with microarrays, a high number of genes (up
to 385) were differentially regulated by a selected number (7) of GOF mutations
expressed in the same genetic background. Surprisingly, the transcriptional
profiles resulting from expression of GOF mutations showed minimal overlap in
co-regulated genes. Only two genes, CgCDR1 and
PUP1 (for PDR1upregulated and encoding a mitochondrial protein), were
commonly upregulated by all tested GOFs. While both genes mediated azole
resistance, although to different extents, their deletions in an azole-resistant
isolate led to a reduction of virulence and decreased tissue burden as compared
to clinical parents. As expected from their role in C. glabrata
virulence, the two genes were expressed as well in vitro and
in vivo. The individual overexpression of these two genes
in a CgPDR1-independent manner could partially restore
phenotypes obtained in clinical isolates. These data therefore demonstrate that
at least these two CgPDR1-dependent and -upregulated genes
contribute to the enhanced virulence of C. glabrata that
acquired azole resistance.
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Affiliation(s)
- Sélène Ferrari
- Institute of Microbiology, University of
Lausanne and University Hospital Center, Lausanne, Switzerland
| | | | - Riccardo Torelli
- Institute of Microbiology, Università
Cattolica del Sacro Cuore, Rome, Italy
| | - Brunella Posteraro
- Institute of Microbiology, Università
Cattolica del Sacro Cuore, Rome, Italy
| | - Dominique Sanglard
- Institute of Microbiology, University of
Lausanne and University Hospital Center, Lausanne, Switzerland
- * E-mail:
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