scholarly journals Azole uptake in Candida auris is strongly correlated with drug resistance

2021 ◽  
Vol 3 (12) ◽  
Author(s):  
Brooke Esquivel ◽  
Theodore C. White
Keyword(s):  
Drug Resistance ◽  
Yeast Species ◽  
Fungal Species ◽  
Drug Uptake ◽  
Drug Resistant ◽  
Strongly Correlated ◽  
Potential Mechanism ◽  
Candida Auris ◽  
Fluconazole Resistance ◽  
Fluconazole Resistant

Analyses of fluconazole uptake in clinical isolates of C. auris, with wide ranging drug resistance profiles, has revealed interesting differences within the species as well as major distinctions from other yeast species. We previously proposed that prevention of drug uptake is a potential mechanism of drug resistance and our C. auris data provide further support for this. We developed an assay using radio-labeled fluconazole to measure intracellular azole accumulation in fungal cells. The assay is performed under glucose-replete conditions to inhibit ATP-dependent efflux. A comparative study measuring fluconazole uptake in 63 C. auris isolates as well as a panel of other species such as C. albicans, S. cerevisiae, C. glabrata, C. krusie, C. lusitanea, C. tropicalis, and C. dublinienses revealed striking C. auris phenotypes that we have not seen in other fungal species. There is a strong correlation between fluconazole resistance and reduced drug uptake in C. auris. Fluconazole-resistant C. auris isolates had reduced levels of intracellular fluconazole accumulation compared to susceptible isolates. Drug-resistant C. auris isolates had the lowest drug accumulation of any of the yeast species tested. Fluconazole-susceptible C. auris isolates had dramatically increased fluconazole accumulation compared to the resistant isolates as well as when compared to other yeast species. Of the 63 C. auris isolates, 28 of 32 (∼88%) resistant isolates had extremely low fluconazole uptake, whereas 15 of 18 (∼83%) susceptible isolates had high fluconazole uptake. This association between reduced drug uptake and resistance could be a C. auris-distinctive mechanism of drug resistance.

Candida auris and Nosocomial Infection

2020 ◽  
Vol 21 (4) ◽  
pp. 365-373 ◽  
Author(s):  
Sweety Dahiya ◽  
Anil K. Chhillar ◽  
Namita Sharma ◽  
Pooja Choudhary ◽  
Aruna Punia ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Pathogenic Fungus ◽  
Control Measures ◽  
Whole Genome Sequence ◽  
Whole Genome ◽  
Drug Resistant ◽  
Candida Auris ◽  
Preventive Control ◽  
Identification Techniques ◽  
Sensitivity Profile

The existence of the multi-drug resistant (MDR) pathogenic fungus, Candida auris came to light in 2009. This particular organism is capable of causing nosocomial infections in immunecompromised persons. This pathogen is associated with consistent candidemia with high mortality rate and presents a serious global health threat. Whole genome sequence (WGS) investigation detected powerful phylogeographic Candida auris genotypes which are specialized to particular geological areas indicating dissemination of particular genotype among provinces. Furthermore, this organism frequently exhibits multidrug-resistance and displays an unusual sensitivity profile. Identification techniques that are commercialized to test Candida auris often show inconsistent results and this misidentification leads to treatment failure which complicates the management of candidiasis. Till date, Candida auris has been progressively recorded from several countries and therefore its preventive control measures are paramount to interrupt its transmission. In this review, we discussed prevalence, biology, drug-resistance phenomena, virulence factors and management of Candida auris infections.

scholarly journals MONITORING THE RESISTANCE OF CLINICAL STRAINS OF CANDIDA YEAST TO FLUCONAZOLE (A BRIEF LITERATURE REVIEW)

2017 ◽  
pp. 70-74 ◽  
Author(s):  
T. M. Zheltikova
Keyword(s):  
Literature Review ◽  
Yeast Species ◽  
Geographical Location ◽  
Vulvovaginal Candidiasis ◽  
Drug Resistant ◽  
The Past ◽  
Fluconazole Resistant ◽  
Resistant Strains ◽  
The Moment ◽  
Drug Resistant Strains

The article analyzes the global and national research on the resistance of Candida yeasts to fluconazole. The studies demonstrate that the formation of resistance is determined by many factors: type of yeast, choice of the antimycotic medication, geographical location, etc. In addition, one can not disregard the socio-economic and even political causes. The frequency of detection of drug-resistant strains of different species of Candida yeast to fluconazole varies across different regions, between countries of the same region, and may vary from year to year within a country. In other words, the formation of yeast resistance/ susceptibility to fluconazole, and to other antifungals alike, is dynamic and may be reversible.Therefore, both global and national studies conducted over the past decades and devoted to the formation of resistance of Candida yeast to azoles, in particular, fluconazole, have shown that it is still the medication of choice for the treatment of candidiasis, including acute vulvovaginal candidiasis, as well as for relief and prevention of exacerbations of recurrent vulvovaginal candidiasis. C. krusei was and remains one of the most fluconazole-resistant yeast species. Other species, such as C. inconspicua and C. norvegensis, the number and incidence of which is too low for the moment to make any statistically valid conclusions, may in the future be added to the list. 

scholarly journals A Zinc Cluster Transcription Factor Contributes to the Intrinsic Fluconazole Resistance of Candida auris

mSphere ◽  
2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Eva-Maria Mayr ◽  
Bernardo Ramírez-Zavala ◽  
Ines Krüger ◽  
Joachim Morschhäuser
Keyword(s):  
Transcription Factor ◽  
Efflux Pumps ◽  
Azole Resistance ◽  
Drug Resistant ◽  
Candida Auris ◽  
Pathogenic Yeast ◽  
Fluconazole Resistance ◽  
Content Type ◽  
Zinc Cluster ◽  
Genes Encoding

ABSTRACT The recently emerged pathogenic yeast Candida auris is a major concern for human health, because it is easily transmissible, difficult to eradicate from hospitals, and highly drug resistant. Most C. auris isolates are resistant to the widely used antifungal drug fluconazole due to mutations in the target enzyme Erg11 and high activity of efflux pumps, such as Cdr1. In the well-studied, distantly related yeast Candida albicans, overexpression of drug efflux pumps also is a major mechanism of acquired fluconazole resistance and caused by gain-of-function mutations in the zinc cluster transcription factors Mrr1 and Tac1. In this study, we investigated a possible involvement of related transcription factors in efflux pump expression and fluconazole resistance of C. auris. The C. auris genome contains three genes encoding Mrr1 homologs and two genes encoding Tac1 homologs, and we generated deletion mutants lacking these genes in two fluconazole-resistant strains from clade III and clade IV. Deletion of TAC1b decreased the resistance to fluconazole and voriconazole in both strain backgrounds, demonstrating that the encoded transcription factor contributes to azole resistance in C. auris strains from different clades. CDR1 expression was not or only minimally affected in the mutants, indicating that Tac1b can confer increased azole resistance by a CDR1-independent mechanism. IMPORTANCE Candida auris is a recently emerged pathogenic yeast that within a few years after its initial description has spread all over the globe. C. auris is a major concern for human health, because it can cause life-threatening systemic infections, is easily transmissible, and is difficult to eradicate from hospital environments. Furthermore, C. auris is highly drug resistant, especially against the widely used antifungal drug fluconazole. Mutations in the drug target and high activity of efflux pumps are associated with azole resistance, but it is not known how drug resistance genes are regulated in C. auris. We have investigated the potential role of several candidate transcriptional regulators in the intrinsic fluconazole resistance of C. auris and identified a transcription factor that contributes to the high resistance to fluconazole and voriconazole of two C. auris strains from different genetic clades, thereby providing insight into the molecular basis of drug resistance of this medically important yeast.

scholarly journals Hospital Specificity, Region Specificity, and Fluconazole Resistance of Candida albicans Bloodstream Isolates

1998 ◽  
Vol 36 (6) ◽  
pp. 1518-1529 ◽  
Author(s):  
M. A. Pfaller ◽  
S. R. Lockhart ◽  
C. Pujol ◽  
J. A. Swails-Wenger ◽  
S. A. Messer ◽  
...  
Keyword(s):  
United States ◽  
Drug Resistance ◽  
Candida Albicans ◽  
Genetic Relatedness ◽  
Computer Assisted ◽  
Specific Probe ◽  
Fluconazole Resistance ◽  
Fluconazole Resistant ◽  
Species Specific ◽  
Close Genetic Relationship

In a survey of bloodstream infection (BSI) isolates across the continental United States, 162 Candida albicans isolates were fingerprinted with the species-specific probe Ca3 and the patterns were analyzed for relatedness with a computer-assisted system. The results demonstrate that particular BSI strains are more highly concentrated in particular geographic locales and that established BSI strains are endemic in some, but not all, hospitals in the study and undergo microevolution in hospital settings. The results, however, indicate no close genetic relationship among fluconazole-resistant BSI isolates in the collection, either from the same geographic locale or the same hospital. This study represents the first of three fingerprinting studies designed to analyze the origin, genetic relatedness, and drug resistance of Candida isolates responsible for BSI.

scholarly journals Yeast species in vulvovaginitis candidosa

2015 ◽  
Vol 156 (1) ◽  
pp. 28-31 ◽  
Author(s):  
Éva Nemes-Nikodém ◽  
Béla Tamási ◽  
Noémi Mihalik ◽  
Eszter Ostorházi
Keyword(s):  
Candida Albicans ◽  
Yeast Species ◽  
Antifungal Susceptibility ◽  
Common Species ◽  
Fungal Species ◽  
Vulvovaginal Candidiasis ◽  
Fungal Culture ◽  
Ionization Time ◽  
Fluconazole Resistant ◽  
Available Information

Introduction: Vulvovaginal candidiasis is the most common mycosis, however, the available information about antifungal susceptibilities of these yeasts is limited. Aim: To compare the gold standard fungal culture with a new molecular identification method and report the incidence of yeast species in vulvovaginitis candidosa. Method: The authors studied 370 yeasts isolated from vulvovaginal candidiasis and identified them by phenotypic and molecular methods. Results: The most common species was Candida albicans (85%), followed by Candida glabrata, and other Candida species. Conclusion: At present there are no recommendations for the evaluation of antifungal susceptibility of pathogenic fungal species occurring in vulvovaginal candidiasis and the natural antifungal resistance of the different species is known only. Matrix Assisted Laser Desorption Ionization Time of Flight identification can be used to differentiate the fluconazole resistant Candida dubliniensis and the sensitive Candida albicans strains. Orv. Hetil., 2015, 156(1), 28–31.

scholarly journals Mutations in TAC1B: a novel genetic determinant of clinical fluconazole resistance in C. auris

2020 ◽  
Author(s):  
Jeffrey M. Rybak ◽  
José F. Muñoz ◽  
Katherine S. Barker ◽  
Josie E. Parker ◽  
Brooke D. Esquivel ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Clinical Isolate ◽  
Multidrug Resistant ◽  
Clinical Isolates ◽  
Resistant Isolate ◽  
Genetic Determinant ◽  
Candida Auris ◽  
Fluconazole Resistance ◽  
Fluconazole Resistant

ABSTRACTCandida auris has emerged as a multidrug-resistant pathogen of great clinical concern. Approximately 90% of clinical C. auris isolates are resistant to fluconazole, the most commonly prescribed antifungal agent, yet it remains unknown what mechanisms underpin this fluconazole resistance. To identify novel mechanisms contributing to fluconazole resistance in C. auris, the fluconazole-susceptible C. auris clinical isolate AR0387 was passaged in media supplemented with fluconazole to generate derivative strains which had acquired increased fluconazole resistance in vitro. Comparative analysis of comprehensive sterol profiles, [3H]-fluconazole uptake, sequencing of C. auris genes homologous to genes known to contribute to fluconazole resistance in other species of Candida, and the relative expression of C. auris ERG11, CDR1, and MDR1 were performed. All fluconazole-evolved derivative strains were found to have acquired mutations in the zinc-cluster transcription factor-encoding gene, TAC1B, and a corresponding increase in CDR1 expression relative to the parental clinical isolate, AR0387. Mutations in TAC1B were also identified in a set of 304 globally distributed C. auris clinical isolates representing each of the four major clades. Introduction of the most common mutation found among fluconazole-resistant clinical isolates of C. auris into the fluconazole-susceptible isolate AR0387, was confirmed to increase fluconazole resistance by 8-fold, and the correction of the same mutation in a fluconazole-resistant isolate, AR0390, decreased fluconazole MIC by 16-fold. Taken together, these data demonstrate that C. auris can rapidly acquire resistance to fluconazole in-vitro, and that mutations in TAC1B significantly contribute to clinical fluconazole resistance.IMPORTANCECandida auris is an emerging multidrug-resistant pathogen of global concern, known to be responsible for outbreaks on six continents and commonly resistant to antifungals. While the vast majority of clinical C. auris isolates are highly resistant to fluconazole, an essential part of the available antifungal arsenal, very little is known about the mechanisms contributing to resistance. In this work, we show that mutations in the transcription factor TAC1B significantly contribute to clinical fluconazole resistance. These studies demonstrate that mutations in TAC1B can arise rapidly in vitro upon exposure to fluconazole, and that a multitude of resistance-associated TAC1B mutations are present among the majority of fluconazole-resistant C. auris isolates from a global collection and appear specific to a subset of lineages or clades. Thus, identification of this novel genetic determinant of resistance significantly adds to the understanding of clinical antifungal resistance in C. auris.

scholarly journals Mutations in TAC1B: a Novel Genetic Determinant of Clinical Fluconazole Resistance in Candida auris

mBio ◽  
2020 ◽  
Vol 11 (3) ◽  
Author(s):  
Jeffrey M. Rybak ◽  
José F. Muñoz ◽  
Katherine S. Barker ◽  
Josie E. Parker ◽  
Brooke D. Esquivel ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Clinical Isolate ◽  
Multidrug Resistant ◽  
Clinical Isolates ◽  
Genetic Determinant ◽  
Candida Auris ◽  
Fluconazole Resistance ◽  
Content Type ◽  
Fluconazole Resistant

ABSTRACT Candida auris has emerged as a multidrug-resistant pathogen of great clinical concern. Approximately 90% of clinical C. auris isolates are resistant to fluconazole, the most commonly prescribed antifungal agent, and yet it remains unknown what mechanisms underpin this fluconazole resistance. To identify novel mechanisms contributing to fluconazole resistance in C. auris, fluconazole-susceptible C. auris clinical isolate AR0387 was passaged in media supplemented with fluconazole to generate derivative strains which had acquired increased fluconazole resistance in vitro. Comparative analyses of comprehensive sterol profiles, [3H]fluconazole uptake, sequencing of C. auris genes homologous to genes known to contribute to fluconazole resistance in other species of Candida, and relative expression levels of C. auris ERG11, CDR1, and MDR1 were performed. All fluconazole-evolved derivative strains were found to have acquired mutations in the zinc-cluster transcription factor-encoding gene TAC1B and to show a corresponding increase in CDR1 expression relative to the parental clinical isolate, AR0387. Mutations in TAC1B were also identified in a set of 304 globally distributed C. auris clinical isolates representing each of the four major clades. Introduction of the most common mutation found among fluconazole-resistant clinical isolates of C. auris into fluconazole-susceptible isolate AR0387 was confirmed to increase fluconazole resistance by 8-fold, and the correction of the same mutation in a fluconazole-resistant isolate, AR0390, decreased fluconazole MIC by 16-fold. Taken together, these data demonstrate that C. auris can rapidly acquire resistance to fluconazole in vitro and that mutations in TAC1B significantly contribute to clinical fluconazole resistance. IMPORTANCE Candida auris is an emerging multidrug-resistant pathogen of global concern, known to be responsible for outbreaks on six continents and to be commonly resistant to antifungals. While the vast majority of clinical C. auris isolates are highly resistant to fluconazole, an essential part of the available antifungal arsenal, very little is known about the mechanisms contributing to resistance. In this work, we show that mutations in the transcription factor TAC1B significantly contribute to clinical fluconazole resistance. These studies demonstrated that mutations in TAC1B can arise rapidly in vitro upon exposure to fluconazole and that a multitude of resistance-associated TAC1B mutations are present among the majority of fluconazole-resistant C. auris isolates from a global collection and appear specific to a subset of lineages or clades. Thus, identification of this novel genetic determinant of resistance significantly adds to the understanding of clinical antifungal resistance in C. auris.

scholarly journals MicroRNA-Based Therapeutics for Drug-Resistant Colorectal Cancer

2021 ◽  
Vol 14 (2) ◽  
pp. 136
Author(s):  
Eunsun Jung ◽  
Jinhyeon Choi ◽  
Jang-Seong Kim ◽  
Tae-Su Han
Keyword(s):  
Colorectal Cancer ◽  
Drug Resistance ◽  
Drug Targets ◽  
Molecular Mechanisms ◽  
Target Genes ◽  
Therapeutic Targets ◽  
Cell Cycle Checkpoints ◽  
Drug Uptake ◽  
Cancer Drug ◽  
Drug Resistant

Although therapeutic approaches for patients with colorectal cancer (CRC) have improved in the past decades, the problem of drug resistance still persists and acts as a major obstacle for effective therapy. Many studies have shown that drug resistance is related to reduced drug uptake, modification of drug targets, and/or transformation of cell cycle checkpoints. A growing body of evidence indicates that several microRNAs (miRNAs) may contribute to the drug resistance to chemotherapy, targeted therapy, and immunotherapy by regulating the drug resistance-related target genes in CRC. These drug resistance-related miRNAs may be used as promising biomarkers for predicting drug response or as potential therapeutic targets for treating patients with CRC. In this review, we summarized the recent discoveries regarding anti-cancer drug-related miRNAs and their molecular mechanisms in CRC. Furthermore, we discussed the challenges associated with the clinical application of miRNAs as biomarkers for the diagnosis of drug-resistant patients and as therapeutic targets for CRC treatment.

scholarly journals Targeting CD44 by CRISPR-Cas9 in Multi-Drug Resistant Osteosarcoma Cells

2018 ◽  
Vol 51 (4) ◽  
pp. 1879-1893 ◽  
Author(s):  
Zheng Xiao ◽  
Jia Wan ◽  
Ayub Abdulle Nur ◽  
Pencheng Dou ◽  
Henry Mankin ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Drug Sensitivity ◽  
3D Cell Culture ◽  
Resistant Cell ◽  
Current Treatment ◽  
Drug Uptake ◽  
Migration And Invasion ◽  
Drug Resistant ◽  
Osteosarcoma Cells ◽  
High Level

Background/Aims: Drug resistance is the main difficulty for the current treatment for osteosarcoma. Cluster of differentiation 44 (CD44) is a receptor for hyaluronic acid (HA) and HA-binding has been proven to participate in various biological tumor activities, including tumor progression, metastasis and drug resistance. In this study, we aimed to determine the effects of CD44 on migration, invasion, proliferation, and the drug-sensitivity of osteosarcoma. Methods: 96 human osteosarcoma tissues from 56 patients were collected to evaluate the expression of CD44 in osteosarcoma tissue by immunohistochemistry. CRISPR-Cas9 system was used to specifically silence CD44 in drug-resistant cell lines (KHOSR2 and U-2OSR2). The migration and invasion activities of cells was demonstrated by wound healing and transwell invasion assay. The proliferation speed of the cells was detected under 3D cell culture condition. Drug resistance of cells was detected by MTT and drug uptake assay. Results: The immunohistochemistry results demonstrated that a high level of CD44 may predict poor survival and higher potential of metastasis, recurrence and drug resistance in patients with osteosarcoma. After knocking-out of CD44 by the CRISPR-Cas9 system, not only the migration and invasion activities of osteosarcoma cells were significantly inhibited, but the drug sensitivity was also enhanced. Conclusion: CD44 silencing could inhibit the development of osteosarcoma migration, invasion, proliferation and ameliorate drug resistance to current treatment in osteosarcoma. This study applies new strategy to target CD44, which may improve the prognosis of osteosarcoma.

scholarly journals Fluconazole-Resistant Candida auris Is Susceptible to Salivary Histatin 5 Killing and to Intrinsic Host Defenses

2017 ◽  
Vol 62 (2) ◽  
Author(s):  
Ruvini U. Pathirana ◽  
Justin Friedman ◽  
Hannah L. Norris ◽  
Ornella Salvatori ◽  
Andrew D. McCall ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Candida Auris ◽  
Fluconazole Resistance ◽  
Content Type ◽  
Histatin 5 ◽  
Cellular Targets ◽  
Highly Sensitive ◽  
Fluconazole Resistant ◽  
Resistant Strains

ABSTRACT Candida auris is a newly identified species causing invasive candidemia and candidiasis. It has broad multidrug resistance (MDR) not observed for other pathogenic Candida species. Histatin 5 (Hst 5) is a well-studied salivary cationic peptide with significant antifungal activity against Candida albicans and is an attractive candidate for treating MDR fungi, since antimicrobial peptides induce minimal drug resistance. We investigated the susceptibility of C. auris to Hst 5 and neutrophils, two first-line innate defenses in the human host. The majority of C. auris clinical isolates, including fluconazole-resistant strains, were highly sensitive to Hst 5: 55 to 90% of cells were killed by use of 7.5 μM Hst 5. Hst 5 was translocated to the cytosol and vacuole in C. auris cells; such translocation is required for the killing of C. albicans by Hst 5. The inverse relationship between fluconazole resistance and Hst 5 killing suggests different cellular targets for Hst 5 than for fluconazole. C. auris showed higher tolerance to oxidative stress than C. albicans, and higher survival within neutrophils, which correlated with resistance to oxidative stress in vitro. Thus, resistance to reactive oxygen species (ROS) is likely one, though not the only, important factor in the killing of C. auris by neutrophils. Hst 5 has broad and potent candidacidal activity, enabling it to combat MDR C. auris strains effectively.

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