scholarly journals Insights into the Unique Nature of the East Asian Clade of the Emerging Pathogenic Yeast Candida auris

2019 ◽  
Vol 57 (4) ◽  
Author(s):  
Rory M. Welsh ◽  
D. Joseph Sexton ◽  
Kaitlin Forsberg ◽  
Snigdha Vallabhaneni ◽  
Anastasia Litvintseva

ABSTRACT The emerging yeast Candida auris can be highly drug resistant, causing invasive infections, and large outbreaks. C. auris went from an unknown pathogen a decade ago to being reported in over thirty countries on six continents. C. auris consists of four discrete clades, based on where the first isolates of the clade were reported, South Asian (clade I), East Asian (clade II), African (clade III), and South American (clade IV). These clades have unique genetic and biochemical characteristics that are important to understand and inform the global response to C. auris. Clade II has been underrepresented in the literature despite being the first one discovered. In this issue of the Journal of Clinical Microbiology, Y. J. Kwon et al. (J Clin Microbiol 57:e01624-18, 2019, https://doi.org/10.1128/JCM.01624-18) describe the largest collection of clinical isolates from Clade II, which is also the longest-running span of clinical cases, 20 years, from any single region to date. Clade II appears to have a propensity for the ear that is uncharacteristic of the other clades, which typically cause invasive infections and large-scale outbreaks. This study provides new information on an understudied lineage of C. auris and has important implications for future surveillance.

Significance It is the only country in South-east Asia with a large-scale nuclear plant, although this was never loaded with fuel. Other countries in the region have tentative plans to develop nuclear power programmes. Impacts The current absence of nuclear power programmes will help avert the diversion of capital from renewable energy development in the region. South-east Asian countries with small, non-power reactors, built for research, will try to maintain these facilities. Across the region, the need for electricity grid investment will increase as more decentralised generation sources are deployed.


2018 ◽  
Vol 63 (3) ◽  
Author(s):  
Nathan P. Wiederhold ◽  
Shawn R. Lockhart ◽  
Laura K. Najvar ◽  
Elizabeth L. Berkow ◽  
Rosie Jaramillo ◽  
...  

ABSTRACTCandida aurisis an emerging pathogen associated with significant mortality and often multidrug resistance. VT-1598, a tetrazole-based fungal CYP51-specific inhibitor, was evaluatedin vitroandin vivoagainstC. auris. Susceptibility testing was performed against 100 clinical isolates ofC. aurisby broth microdilution. Neutropenic mice were infected intravenously withC. auris, and treatment began 24 h postinoculation with a vehicle control, oral VT-1598 (5, 15, and 50 mg/kg of body weight once daily), oral fluconazole (20 mg/kg once daily), or intraperitoneal caspofungin (10 mg/kg once daily), which continued for 7 days. Fungal burden was assessed in the kidneys and brains on day 8 in the fungal burden arm and on the days the mice succumbed to infection or on day 21 in the survival arm. VT-1598 plasma trough concentrations were also assessed on day 8. VT-1598 demonstratedin vitroactivity againstC. auris, with a mode MIC of 0.25 μg/ml and MICs ranging from 0.03 to 8 μg/ml. Treatment with VT-1598 resulted in significant and dose-dependent improvements in survival (median survival, 15 and >21 days for VT-1598 at 15 and 50 mg/kg, respectively) and reductions in kidney and brain fungal burden (reductions of 1.88 to 3.61 log10CFU/g) compared to the control (5 days). The reductions in fungal burden correlated with plasma trough concentrations. Treatment with caspofungin, but not fluconazole, also resulted in significant improvements in survival and reductions in fungal burden compared to those with the control. These results suggest that VT-1598 may be a future option for the treatment of invasive infections caused byC. auris.


mSphere ◽  
2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Eva-Maria Mayr ◽  
Bernardo Ramírez-Zavala ◽  
Ines Krüger ◽  
Joachim Morschhäuser

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.


2017 ◽  
Vol 55 (8) ◽  
pp. 2445-2452 ◽  
Author(s):  
Milena Kordalewska ◽  
Yanan Zhao ◽  
Shawn R. Lockhart ◽  
Anuradha Chowdhary ◽  
Indira Berrio ◽  
...  

ABSTRACT Candida auris is an emerging multidrug-resistant fungal pathogen causing nosocomial and invasive infections associated with high mortality. C. auris is commonly misidentified as several different yeast species by commercially available phenotypic identification platforms. Thus, there is an urgent need for a reliable diagnostic method. In this paper, we present fast, robust, easy-to-perform and interpret PCR and real-time PCR assays to identify C. auris and related species: Candida duobushaemulonii , Candida haemulonii , and Candida lusitaniae . Targeting rDNA region nucleotide sequences, primers specific for C. auris only or C. auris and related species were designed. A panel of 140 clinical fungal isolates was used in both PCR and real-time PCR assays followed by electrophoresis or melting temperature analysis, respectively. The identification results from the assays were 100% concordant with DNA sequencing results. These molecular assays overcome the deficiencies of existing phenotypic tests to identify C. auris and related species.


2020 ◽  
Vol 64 (4) ◽  
Author(s):  
Brittany O’Brien ◽  
Sudha Chaturvedi ◽  
Vishnu Chaturvedi

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.


2019 ◽  
Vol 63 (11) ◽  
Author(s):  
Nathan P. Wiederhold ◽  
Laura K. Najvar ◽  
Karen J. Shaw ◽  
Rosie Jaramillo ◽  
Hoja Patterson ◽  
...  

ABSTRACT The emerging pathogenic yeast Candida auris is associated with antifungal resistance and high mortality. The novel antifungal agent manogepix (APX001A) inhibits glycosylphosphatidylinositol-anchored protein maturation and has demonstrated activity against numerous pathogenic fungi, including C. auris. Our objective was to evaluate the in vivo efficacy of fosmanogepix, the N-phosphonooxymethyl prodrug (APX001), following delayed initiation of therapy in a murine model of C. auris invasive candidiasis. Neutropenic mice were intravenously infected with a fluconazole-resistant clinical isolate of C. auris. Twenty-four hours postinoculation, treatment began with vehicle control, fosmanogepix (104 and 130 mg/kg of body weight by intraperitoneal injection three times daily, or intraperitoneal 260 mg/kg twice daily), fluconazole (20 mg/kg by oral gavage once daily), or caspofungin (intraperitoneal 10 mg/kg once daily) and continued for 7 days. Fungal burden was assessed via colony count in the kidneys and brains on day 8 in the fungal burden arm and on day 21 as the mice became moribund in the survival arm. Significant improvements in survival were observed in each group administered fosmanogepix and caspofungin. Similarly, reductions in fungal burden were also observed in both the kidneys and brains of mice treated with the highest dose of fosmanogepix in the fungal burden arm and in each fosmanogepix group and with caspofungin in the survival arm. In contrast, no improvements in survival or reductions in fungal burden were observed in mice treated with fluconazole. These results demonstrate that fosmanogepix is effective in vivo against fluconazole-resistant C. auris even when therapy is delayed.


2017 ◽  
Vol 55 (10) ◽  
pp. 2996-3005 ◽  
Author(s):  
Rory M. Welsh ◽  
Meghan L. Bentz ◽  
Alicia Shams ◽  
Hollis Houston ◽  
Amanda Lyons ◽  
...  

ABSTRACTThe emerging multidrug-resistant pathogenic yeastCandida aurisrepresents a serious threat to global health. Unlike most otherCandidaspecies, this organism appears to be commonly transmitted within health care facilities and causes health care-associated outbreaks. To better understand the epidemiology of this emerging pathogen, we investigated the ability ofC. auristo persist on plastic surfaces common in health care settings compared with that ofCandida parapsilosis, a species known to colonize the skin and plastics. Specifically, we compiled comparative and quantitative data essential to understanding the vehicles of spread and the ability of both species to survive and persist on plastic surfaces under controlled conditions (25°C and 57% relative humidity), such as those found in health care settings. When a test suspension of 104cells was applied and dried on plastic surfaces,C. aurisremained viable for at least 14 days andC. parapsilosisfor at least 28 days, as measured by CFU. However, survival measured by esterase activity was higher forC. auristhanC. parapsilosisthroughout the 28-day study. Given the notable length of timeCandidaspecies survive and persist outside their host, we developed methods to more effectively cultureC. aurisfrom patients and their environment. Using our enrichment protocol, public health laboratories and researchers can now readily isolateC. aurisfrom complex microbial communities (such as patient skin, nasopharynx, and stool) as well as environmental biofilms, in order to better understand and preventC. auriscolonization and transmission.


2017 ◽  
Vol 61 (8) ◽  
Author(s):  
Thomas Lodise ◽  
Michael J. Ye ◽  
Qi Zhao

ABSTRACT This large-scale retrospective analysis (n = 60,551) of the Premier inpatient database (1 January 2011 to 31 December 2014) found an overall prevalence of carbapenem-resistant Enterobacteriaceae strains of 2.3% (range, 0.9% to 5.8% by geographic region) among patients with infections due to Enterobacteriaceae. Ongoing monitoring and development of decision support tools/algorithms are needed for identification of high-risk patients.


mSphere ◽  
2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Mark V. Horton ◽  
Chad J. Johnson ◽  
John F. Kernien ◽  
Tarika D. Patel ◽  
Brandon C. Lam ◽  
...  

The emerging fungal pathogen Candida auris causes invasive infections and is spreading in hospitals worldwide. Why this species exhibits the capacity to transfer efficiently among patients is unknown. Our findings reveal that C. auris forms high-burden biofilms in conditions mimicking sweat on the skin surface. These adherent biofilm communities persist in environmental conditions expected in the hospital setting. Using a pig skin model, we show that C. auris also forms high-burden biofilm structures on the skin surface. Identification of this mode of growth sheds light on how this recently described pathogen persists in hospital settings and spreads among patients.


2018 ◽  
Vol 31 (6) ◽  
pp. 1271-1282 ◽  
Author(s):  
Simon Krogh

Purpose Existing research on the organizational implications of the introduction of new information technology (IT) has neglected to focus on the anticipation of organizational change. In this paper, the author examines the extended pre-implementation phase prior to the introduction of the largest-ever health IT (HIT) implementation in Denmark. The purpose of this paper is to expand the conceptualization of organizational change to include the neglected pre-implementation phase preceding large-scale organizational change projects. Design/methodology/approach The research is based on qualitative data consisting of interviews, documents and observations gathered during a three-year research project in the Danish health sector. An important source of methodical inspiration has been grounded theory, which has allowed the pertinent interview themes to evolve and allowed for the gradual development of a theoretical framework. Findings The main finding of this paper is that the anticipatory pre-implementation phase is not simply passive waiting time for organizational members. Evidence from a three-year research project demonstrates how organizational members engage in recurring patterns of sensemaking, positioning and scripting of possible futures in preparation for the organizational changes that next generation HIT imposes. The study argues that resistance to organizational change may be better understood as resistance to having to give up institutionalized rights and responsibilities. Originality/value The paper offers a conceptual model—the anticipation cycle—that enables the systematic analysis of the relational mechanisms at work when organizational members are preparing for pending organizational change. Early analysis based on the anticipation cycle enables organizations and scholars to bring previously black-boxed anticipatory patterns into the equation of organizational change.


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