Potent Synergistic Interactions between Lopinavir and Azole Antifungal Drugs against Emerging Multidrug-Resistant Candida auris

ABSTRACTThe limited therapeutic options and the recent emergence of multidrug-resistant Candida species present a significant challenge to human medicine and underscore the need for novel therapeutic approaches. Drug repurposing appears as a promising tool to augment the activity of current azole antifungals, especially against multidrug-resistant Candida auris. In this study, we evaluated the fluconazole chemosensitization activities of 1,547 FDA-approved drugs and clinical molecules against azole-resistant C. auris. This led to the discovery that lopinavir, an HIV protease inhibitor, is a potent agent capable of sensitizing C. auris to the effect of azole antifungals. At a therapeutically achievable concentration, lopinavir exhibited potent synergistic interactions with azole drugs, particularly with itraconazole against C. auris (fractional inhibitory concentration index [ΣFICI] ranged from 0.04 to 0.09). Additionally, the lopinavir/itraconazole combination enhanced the survival rate of C. auris-infected Caenorhabditis elegans by 90% and reduced the fungal burden in infected nematodes by 88.5% (P < 0.05) relative to that of the untreated control. Furthermore, lopinavir enhanced the antifungal activity of itraconazole against other medically important Candida species, including C. albicans, C. tropicalis, C. krusei, and C. parapsilosis. Comparative transcriptomic profiling and mechanistic studies revealed that lopinavir was able to significantly interfere with the glucose permeation and ATP synthesis. This compromised the efflux ability of C. auris and consequently enhanced the susceptibility to azole drugs, as demonstrated by Nile red efflux assays. Altogether, these findings present lopinavir as a novel, potent, and broad-spectrum azole-chemosensitizing agent that warrants further investigation against recalcitrant Candida infections.

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In Vitro Evaluation of Antifungal Drug Combinations against Multidrug-Resistant Candida auris Isolates from New York Outbreak

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02195-19 ◽

2020 ◽

Vol 64 (4) ◽

Cited By ~ 6

Author(s):

Brittany O’Brien ◽

Sudha Chaturvedi ◽

Vishnu Chaturvedi

Keyword(s):

New York ◽

Drug Combination ◽

Multidrug Resistant ◽

Drug Combinations ◽

Health Care Facilities ◽

Antifungal Drugs ◽

Candida Auris ◽

Pathogenic Yeast ◽

Content Type

ABSTRACT Since 2016, New York hospitals and health care facilities have faced an unprecedented outbreak of the pathogenic yeast Candida auris. We tested over 1,000 C. auris isolates from affected facilities and found high resistance to fluconazole (MIC > 256 mg/liter) and variable resistance to other antifungal drugs. Therefore, we tested if two-drug combinations are effective in vitro against multidrug-resistant C. auris. Broth microdilution antifungal combination plates were custom manufactured by TREK Diagnostic System. We used 100% inhibition endpoints for the drug combination as reported earlier for the intra- and interlaboratory agreements against Candida species. The results were derived from 12,960 readings, for 15 C. auris isolates tested against 864 two-drug antifungal combinations for nine antifungal drugs. Flucytosine (5FC) at 1.0 mg/liter potentiated the most combinations. For nine C. auris isolates resistant to amphotericin B (AMB; MIC ≥ 2.0 mg/liter), AMB-5FC (0.25/1.0 mg/liter) yielded 100% inhibition. Six C. auris isolates resistant to three echinocandins (anidulafungin [AFG], MIC ≥ 4.0 mg/liter; caspofungin [CAS], MIC ≥ 2.0 mg/liter; and micafungin [MFG], MIC ≥ 4.0 mg/liter) were 100% inhibited by AFG-5FC and CAS-5FC (0.0078/1 mg/liter) and MFG-5FC (0.12/1 mg/liter). None of the combinations were effective for C. auris 18-1 and 18-13 (fluconazole [FLC] > 256 mg/liter, 5FC > 32 mg/liter) except MFG-5FC (0.1/0.06 mg/liter). Thirteen isolates with a high voriconazole (VRC) MIC (>2 mg/liter) were 100% inhibited by the VRC-5FC (0.015/1 mg/liter). The simplified two-drug combination susceptibility test format would permit laboratories to provide clinicians and public health experts with additional data to manage multidrug-resistant C. auris.

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In Vitro Activity of Manogepix against Multidrug-Resistant and Panresistant Candida auris from the New York Outbreak

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01124-20 ◽

2020 ◽

Vol 64 (11) ◽

Cited By ~ 1

Author(s):

YanChun Zhu ◽

Shannon Kilburn ◽

Mili Kapoor ◽

Sudha Chaturvedi ◽

Karen Joy Shaw ◽

...

Keyword(s):

New York ◽

Fungal Infections ◽

Geometric Mean ◽

Multidrug Resistant ◽

Antifungal Drugs ◽

New Drugs ◽

Wild Type ◽

Candida Auris ◽

Content Type

ABSTRACT An ongoing Candida auris outbreak in the New York metropolitan area is the largest recorded to date in North America. Laboratory surveillance revealed NY C. auris isolates are resistant to fluconazole, with variable resistance to other currently used broad-spectrum antifungal drugs, and that several isolates are panresistant. Thus, there is an urgent need for new drugs with a novel mechanism of action to combat the resistance challenge. Manogepix (MGX) is a first-in-class agent that targets the fungal Gwt1 enzyme. The prodrug fosmanogepix is currently in phase 2 clinical development for the treatment of fungal infections. We evaluated the susceptibility of 200 New York C. auris isolates to MGX and 10 comparator drugs using CLSI methodology. MGX demonstrated lower MICs than comparators (MIC50 and MIC90, 0.03 mg/liter; range, 0.004 to 0.06 mg/liter). The local epidemiological cutoff value (ECV) for MGX indicated all C. auris isolates were within the population of wild-type (WT) strains; 0.06 mg/liter defines the upper limit of wild type (UL-WT). MGX was 8- to 32-fold more active than the echinocandins, 16- to 64-fold more active than the azoles, and 64-fold more active than amphotericin B. No differences were found in the MGX or comparators’ MIC50, MIC90, or geometric mean (GM) values when subsets of clinical, surveillance, and environmental isolates were evaluated. The range of MGX MIC values for six C. auris panresistant isolates was 0.008 to 0.015 mg/liter, and the median and mode MIC values were 0.015 mg/liter, demonstrating that MGX retains activity against these isolates. These data support further clinical evaluation of fosmanogepix for the treatment of C. auris infections, including highly resistant isolates.

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Combined Antifungal Resistance and Biofilm Tolerance: the Global Threat of Candida auris

mSphere ◽

10.1128/msphere.00458-19 ◽

2019 ◽

Vol 4 (4) ◽

Cited By ~ 24

Author(s):

Ryan Kean ◽

Gordon Ramage

Keyword(s):

Clinical Importance ◽

Multidrug Resistant ◽

Antifungal Resistance ◽

Antifungal Drugs ◽

Medical Mycology ◽

Candida Auris ◽

Content Type ◽

Echinocandin Resistance ◽

Global Threat ◽

The Impact

ABSTRACT The enigmatic yeast Candida auris has emerged over the last decade and rapidly penetrated our consciousness. The global threat from this multidrug-resistant yeast has generated a call to arms from within the medical mycology community. Over the past decade, our understanding of how this yeast has spread globally, its clinical importance, and how it tolerates and resists antifungal agents has expanded. This review highlights the clinical importance of antifungal resistance in C. auris and explores our current understanding of the mechanisms associated with azole, polyene, and echinocandin resistance. We also discuss the impact of phenotypic tolerance, with particular emphasis on biofilm-mediated resistance, and present new pipelines of antifungal drugs that promise new hope in the management of C. auris infection.

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Pseudohyphal Growth of the Emerging Pathogen Candida auris Is Triggered by Genotoxic Stress through the S Phase Checkpoint

mSphere ◽

10.1128/msphere.00151-20 ◽

2020 ◽

Vol 5 (2) ◽

Cited By ~ 6

Author(s):

Gustavo Bravo Ruiz ◽

Zoe K. Ross ◽

Neil A. R. Gow ◽

Alexander Lorenz

Keyword(s):

Fungal Pathogens ◽

Genotoxic Stress ◽

Multidrug Resistant ◽

S Phase ◽

Antifungal Drugs ◽

Yeast Cells ◽

Candida Auris ◽

Content Type ◽

Pseudohyphal Growth ◽

S Phase Checkpoint

ABSTRACT The morphogenetic switching between yeast cells and filaments (true hyphae and pseudohyphae) is a key cellular feature required for full virulence in many polymorphic fungal pathogens, such as Candida albicans. In the recently emerged yeast pathogen Candida auris, occasional elongation of cells has been reported. However, environmental conditions and genetic triggers for filament formation have remained elusive. Here, we report that induction of DNA damage and perturbation of replication forks by treatment with genotoxins, such as hydroxyurea, methyl methanesulfonate, and the clinically relevant fungistatic 5-fluorocytosine, cause filamentation in C. auris. The filaments formed were characteristic of pseudohyphae and not parallel-sided true hyphae. Pseudohyphal growth is apparently signaled through the S phase checkpoint and, interestingly, is Tup1 independent in C. auris. Intriguingly, the morphogenetic switching capability is strain specific in C. auris, highlighting the heterogenous nature of the species as a whole. IMPORTANCE Candida auris is a newly emerged fungal pathogen of humans. This species was first reported in 2009 when it was identified in an ear infection of a patient in Japan. However, despite intense interest in this organism as an often multidrug-resistant fungus, there is little knowledge about its cellular biology. During infection of human patients, fungi are able to change cell shape from ellipsoidal yeast cells to elongated filaments to adapt to various conditions within the host organism. There are different types of filaments, which are triggered by reactions to different cues. Candida auris fails to form filaments when exposed to triggers that stimulate yeast filament morphogenesis in other fungi. Here, we show that it does form filaments when its DNA is damaged. These conditions might arise when Candida auris cells interact with host immune cells or during growth in certain host tissues (kidney or bladder) or during treatment with antifungal drugs.

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Synergistic interactions of sulfamethoxazole and azole antifungal drugs against emerging multidrug-resistant Candida auris

International Journal of Antimicrobial Agents ◽

10.1016/j.ijantimicag.2018.08.016 ◽

2018 ◽

Vol 52 (6) ◽

pp. 754-761 ◽

Cited By ~ 25

Author(s):

Hassan E. Eldesouky ◽

Xiaoyan Li ◽

Nader S. Abutaleb ◽

Haroon Mohammad ◽

Mohamed N. Seleem

Keyword(s):

Multidrug Resistant ◽

Antifungal Drugs ◽

Candida Auris ◽

Synergistic Interactions

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The Two-Component Response Regulator Ssk1 and the Mitogen-Activated Protein Kinase Hog1 Control Antifungal Drug Resistance and Cell Wall Architecture of Candida auris

mSphere ◽

10.1128/msphere.00973-20 ◽

2020 ◽

Vol 5 (5) ◽

Author(s):

Raju Shivarathri ◽

Sabrina Jenull ◽

Anton Stoiber ◽

Manju Chauhan ◽

Rounik Mazumdar ◽

...

Keyword(s):

Cell Wall ◽

Multidrug Resistance ◽

Response Regulator ◽

Multidrug Resistant ◽

Antifungal Drugs ◽

Antifungal Drug ◽

Candida Auris ◽

Content Type ◽

Antifungal Drug Resistance ◽

Two Component

ABSTRACT Candida auris is an emerging multidrug-resistant human fungal pathogen refractory to treatment by several classes of antifungal drugs. Unlike other Candida species, C. auris can adhere to human skin for prolonged periods of time, allowing for efficient skin-to-skin transmission in the hospital environments. However, molecular mechanisms underlying pronounced multidrug resistance and adhesion traits are poorly understood. Two-component signal transduction and mitogen-activated protein (MAP) kinase signaling are important regulators of adherence, antifungal drug resistance, and virulence. Here, we report that genetic removal of SSK1 encoding a response regulator and the mitogen-associated protein kinase HOG1 restores the susceptibility to both amphotericin B (AMB) and caspofungin (CAS) in C. auris clinical strains. The loss of SSK1 and HOG1 alters membrane lipid permeability, cell wall mannan content, and hyperresistance to cell wall-perturbing agents. Interestingly, our data reveal variable functions of SSK1 and HOG1 in different C. auris clinical isolates, suggesting a pronounced genetic plasticity affecting cell wall function, stress adaptation, and multidrug resistance. Taken together, our data suggest that targeting two-component signal transduction systems could be suitable for restoring C. auris susceptibility to antifungal drugs. IMPORTANCE Candida auris is an emerging multidrug-resistant (MDR) fungal pathogen that presents a serious global threat to human health. The Centers for Disease Control and Prevention (CDC) have classified C. auris as an urgent threat to public health for the next decade due to its major clinical and economic impact and the lack of effective antifungal drugs and because of future projections concerning new C. auris infections. Importantly, the Global Antimicrobial Resistance Surveillance System (GLASS) has highlighted the need for more robust and efficacious global surveillance schemes enabling the identification and monitoring of antifungal resistance in Candida infections. Despite the clinical relevance of C. auris infections, our overall understanding of its pathophysiology and virulence, its response to human immune surveillance, and the molecular basis of multiple antifungal resistance remains in its infancy. Here, we show a marked phenotypic plasticity of C. auris clinical isolates. Further, we demonstrate critical roles of stress response mechanisms in regulating multidrug resistance and show that cell wall architecture and composition are key elements that determine antifungal drug susceptibilities. Our data promise new therapeutic options to treat drug-refractory C. auris infections.

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1579. Multidrug-Resistant Candida auris Isolates From New York Hospitals and Healthcare Facilities Are Susceptible to Antifungal Combinations

Open Forum Infectious Diseases ◽

10.1093/ofid/ofz360.1443 ◽

2019 ◽

Vol 6 (Supplement_2) ◽

pp. S576-S577

Author(s):

Brittany O’Brien ◽

Sudha Chaturvedi ◽

Vishnu Chaturvedi

Keyword(s):

New York ◽

Diagnostic System ◽

Multidrug Resistant ◽

Drug Combinations ◽

Antifungal Drugs ◽

Drug Resistant ◽

Candida Auris ◽

Current Case ◽

Healthcare Facilities ◽

Broth Microdilution Method

Abstract Background Candida auris outbreak continues unabated in New York with the current case counts exceeding 300 patients. We used a modification of standard CLSI broth microdilution method (BMD) if two-drug combinations are efficacious against C. auris isolates with high-resistance to fluconazole (FZ, MIC50 >256 mg/L), and variable resistance to other broad-spectrum antifungal drugs. Methods BMD plates were custom-designed and quality controlled by TREK Diagnostic System. The combination tests of 15 drug-resistant C. auris involved microtiter wells with the initial 144 two-drug combinations and their two-fold dilutions (1/2–1/32) to get 864 two-drug combinations finally. We utilized MIC100 endpoints for the drug combination readings as reported earlier for the intra- and inter-laboratory agreements obtained against Candida species and Aspergillus fumigatus (Antimicrob Agents Chemother. 2015. 59:1759–1766). We also tested minimum fungicidal concentrations (MFC). Results We tested all possible 864 two-drug antifungal combinations for nine antifungal drugs in use to yield 12,960 MIC100 readings, and MFC readings for 15 C. auris isolates. Flucytosine (FLC) at 2.0 mg/L potentiated most successful combinations with other drugs. Micafungin (MFG), Anidulafungin (AFG), Caspofungin (CAS) at individual concentrations of 0.25 mg/L combined well with FLC (2.0 mg/L) to yield MIC100 for 14, 13, and 12 of 15 C. auris isolates tested, respectively. MFG/FLC combination was also fungicidal for 4 of 15 isolates. AMB / FLC (0.25/1.0 mg/L) yielded MIC100 for 13 isolates and MFC for three test isolates. Posaconazole (POS), and Isavuconazole (ISA) and Voriconazole (VRC) also combined well with FLC (0.25/2.0 mg/L) to yield MIC100 for 12, 13, and 13 isolates, respectively. POS/FLC combination was fungicidal for three isolates. Conclusion We identified seven two drug-combinations of antifungals efficacious against drug-resistant C. auris strains. The modified BMD combination susceptibility testing could be used by the clinical laboratories to assist providers with the selection of optimal treatment for C. auris candidemia. Disclosures All authors: No reported disclosures.

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Environmental Isolation of Candida auris from the Coastal Wetlands of Andaman Islands, India

mBio ◽

10.1128/mbio.03181-20 ◽

2021 ◽

Vol 12 (2) ◽

Cited By ~ 1

Author(s):

Parth Arora ◽

Prerna Singh ◽

Yue Wang ◽

Anamika Yadav ◽

Kalpana Pawar ◽

...

Keyword(s):

Salt Marsh ◽

Coastal Wetlands ◽

Ecological Niche ◽

Multidrug Resistant ◽

Sandy Beaches ◽

Andaman Islands ◽

Human Pathogen ◽

Candida Auris ◽

Content Type ◽

The Indian Ocean

ABSTRACT Candida auris is a multidrug resistant pathogen that presents a serious global threat to human health. As C. auris is a newly emerged pathogen, several questions regarding its ecological niche remain unexplored. While species closely related to C. auris have been detected in different environmental habitats, little is known about the natural habitat(s) of C. auris. Here, we explored the virgin habitats around the very isolated Andaman Islands in the Indian Ocean for evidence of C. auris. We sampled coastal wetlands, including rocky shores, sandy beaches, tidal marshes, and mangrove swamps, around the Andaman group of the Andaman & Nicobar Islands, Union Territory, in India. Forty-eight samples of sediment soil and seawater were collected from eight sampling sites representing the heterogeneity of intertidal habitats across the east and west coast of South Andaman district. C. auris was isolated from two of the eight sampling sites, a salt marsh and a sandy beach. Interestingly, both multidrug-susceptible and multidrug-resistant C. auris isolates were found in the sample. Whole-genome sequencing analysis clustered the C. auris isolates into clade I, showing close similarity to other isolates from South Asia. Isolation of C. auris from the tropical coastal environment suggests its association with the marine ecosystem. The fact that viable C. auris was detected in the marine habitat confirms C. auris survival in harsh wetlands. However, the ecological significance of C. auris in salt marsh wetland and sandy beaches to human infections remains to be explored. IMPORTANCE Candida auris is a recently emerged multidrug-resistant fungal pathogen capable of causing severe infections in hospitalized patients. Despite its recognition as a human pathogen a decade ago, so far the natural ecological niche(s) of C. auris remains enigmatic. A previous hypothesis suggested that C. auris might be native to wetlands, that its emergence as a human pathogen might have been linked to global warming effects on wetlands, and that its enrichment in that ecological niche was favored by the ability of C. auris for thermal tolerance and salinity tolerance. To understand the mystery of environmental niches of C. auris, we explored the coastal wetland habitat around the very isolated Andaman Islands in the Indian Ocean. C. auris was isolated from the virgin habitats of salt marsh area with no human activity and from a sandy beach. C. auris isolation from the marine wetlands suggests that prior to its recognition as a human pathogen, it existed as an environmental fungus.

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In Vitro Antifungal Combination of Flucytosine with Amphotericin B, Voriconazole, or Micafungin against Candida auris Shows No Antagonism

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01393-19 ◽

2019 ◽

Vol 63 (12) ◽

Cited By ~ 8

Author(s):

A. L. Bidaud ◽

F. Botterel ◽

A. Chowdhary ◽

E. Dannaoui

Keyword(s):

Amphotericin B ◽

Inhibitory Concentration ◽

Geometric Mean ◽

Multidrug Resistant ◽

Candida Auris ◽

Content Type ◽

Hospital Acquired Infections ◽

Resistant Mutants ◽

Hospital Acquired

ABSTRACT Candida auris is an emerging, multidrug-resistant pathogen responsible for invasive hospital-acquired infections. Flucytosine is an effective anti-Candida species drug, but which cannot be used as a monotherapy because of the risk of development of resistant mutants during treatment. It is, therefore, noteworthy to test possible combinations with flucytosine that may have a synergistic interaction. In this study, we determined the in vitro interaction between flucytosine and amphotericin B, micafungin, or voriconazole. These combinations have been tested against 15 C. auris isolates. The MIC ranges (geometric mean [Gmean]) of flucytosine, amphotericin B, micafungin, and voriconazole were 0.125 to 1 μg/ml (0.42 μg/ml), 0.25 to 1 μg/ml (0.66 μg/ml), 0.125 to 0.5 μg/ml (0.3 μg/ml), and 0.03 to 4 μg/ml (1.05 μg/ml), respectively. When tested in combination, indifferent interactions were mostly observed with fractional inhibitory concentration index values from 0.5 to 1, 0.31 to 1.01, and 0.5 to 1.06 for the combinations of flucytosine with amphotericin B, micafungin, and voriconazole, respectively. A synergy was observed for the strain CBS 10913 from Japan. No antagonism was observed for any combination. The combination of flucytosine with amphotericin B or micafungin may be relevant for the treatment of C. auris infections.

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2267. Epidemiology of Candida auris Candidemia in a Teaching Hospital in North of Oman: One-Year Survival

Open Forum Infectious Diseases ◽

10.1093/ofid/ofz360.1945 ◽

2019 ◽

Vol 6 (Supplement_2) ◽

pp. S776-S776

Author(s):

Arash Eatemadi ◽

Aiman Al Wahibi ◽

Hilal Al shibli ◽

Ali Al reesi

Keyword(s):

Public Health ◽

Teaching Hospital ◽

Multidrug Resistant ◽

Hospital Environment ◽

Fungal Treatment ◽

Candida Auris ◽

Coagulase Negative Staphylococci ◽

Central Public Health ◽

Antibiotic Susceptibility Test ◽

Recent Emergence

Abstract Background Recent emergence of Candida auris as a multidrug resistant fungal pathogen, is a serious concerns for public health. However, there is a paucity of reported cases from Oman. Literature search resulted in finding only 7 cases from Oman, reporting C. auris infections in the articles first published in 2017. However, the rate of isolatin is increasing. Methods In this study, we included the results of all positive blood cultures of C. auris in Suhar teaching hospital from May 2018 (date of first detection) till end of April 2019. Further confirmation of the species was performed by MALDI-TOF and antibiotic susceptibility test (AST) by Vitek 2 in central public health laboratory (CPHL) of Oman. Results We detected 13 patients (9 females, 4 males). The mean age was 58.61% years (28–76 years). All candidemic patients had serious underlying conditions, including prolonged hospital stay or extensive and prolonged antimicrobial exposure or medical comorbidities (8 of 13). The time from hospital admission to onset of C. auris candidemia was 8–49 days, with a median of approximately 27 days. The most common isolated co- pathogen from blood culture was K. pneumonia (without regard to Coagulase-negative staphylococci). As average, every patient received 4.8 kind of different antibiotics in mean 88 doses before candidemia developed and piperacillin–tazobactam was the most common used antibiotics. AST was done just for 5 patients and revealed high-level resistance to fluconazole and Amphotricin B while, Echinocandins (anidulafungin, caspofungin) were fully sensitive and voricunazole had intermediate sensitivity. Mean duration of anti-fungal treatment was 12.5 days (5 – 26 days). 8 patients treated by Echinocandins (4/8 died), 4 by Fluconazole (3/4 died) and one without treatment discharged. 30-day all-cause mortality was 61.5%. Conclusion In Oman, C. auris has been reported from many hospitals. Resistance to several antifungal agents and persistence in the hospital environment make this organism a potential menace for the treating physician and the infection control personnel. In our hospital, every candidemic patient should be treated with Echinocandins and assumed to be resistant to Fluconazole until proven otherwise according to results of AST. Disclosures All authors: No reported disclosures.

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