Dataset Information

Understanding Echinocandin Resistance in the Emerging Pathogen Candida auris.

ABSTRACT: Candida auris has simultaneously emerged on five continents as a fungal pathogen causing nosocomial outbreaks. The challenges in the treatment of C. auris infections are the variable antifungal susceptibility profiles among clinical isolates and the development of resistance to single or multiple classes of available antifungal drugs. Here, the in vitro susceptibility to echinocandin antifungal drugs was determined and FKS1 sequencing was performed on 106 C. auris clinical isolates. Four isolates were identified to be resistant to all tested echinocandins (MIC ? 4 mg/liter) and harbored an S639F mutation in FKS1 hot spot region 1. All remaining isolates were FKS1 wild type (WT) and echinocandin susceptible, with micafungin being the most potent echinocandin (MIC50 = 0.125 mg/liter). Antifungal susceptibility testing with caspofungin was challenging due to the fact that all FKS1 WT isolates exhibited an Eagle effect (also known as the paradoxical growth effect), which occurred at various intensities. To assess whether the Eagle effect resulted in pharmacodynamic resistance, 8 representative isolates were evaluated for their in vivo drug response in a murine model of invasive candidiasis. All isolates were susceptible to caspofungin at a human therapeutic dose, except for those harboring the S639F mutation. The data suggest that only isolates carrying mutations in FKS1 are echinocandin resistant and that routine in vitro testing of C. auris isolates for susceptibility to caspofungin by the broth microdilution method should be viewed cautiously or avoided.

SUBMITTER: Kordalewska M

PROVIDER: S-EPMC5971591 | biostudies-literature | 2018 Jun

REPOSITORIES: biostudies-literature

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Understanding Echinocandin Resistance in the Emerging Pathogen Candida auris.

Kordalewska Milena M Lee Annie A Park Steven S Berrio Indira I Chowdhary Anuradha A Zhao Yanan Y Perlin David S DS

Antimicrobial agents and chemotherapy 20180525 6

Candida auris has simultaneously emerged on five continents as a fungal pathogen causing nosocomial outbreaks. The challenges in the treatment of C. auris infections are the variable antifungal susceptibility profiles among clinical isolates and the development of resistance to single or multiple classes of available antifungal drugs. Here, the in vitro susceptibility to echinocandin antifungal drugs was determined and FKS1 sequencing was performed on 106 C. auris< ...[more]

PMID: 29632013

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Project description:Candida auris is a recently described pathogenic fungus that is causing invasive outbreaks on all continents. The fungus is of high concern given the numbers of multidrug-resistant strains that have been isolated in distinct sites across the globe. The fact that its diagnosis is still problematic suggests that the spreading of the pathogen remains underestimated. Notably, the molecular mechanisms of virulence and antifungal resistance employed by this new species are largely unknown. In the present work, we compared two clinical isolates of C. auris with distinct drug susceptibility profiles and a Candida albicans reference strain using a multi-omics approach. Our results show that, despite the distinct drug resistance profile, both C. auris isolates appear to be very similar, albeit with a few notable differences. However, compared to C. albicans both C. auris isolates have major differences regarding their carbon utilization and downstream lipid and protein content, suggesting a multifactorial mechanism of drug resistance. The molecular profile displayed by C. auris helps to explain the antifungal resistance and virulence phenotypes of this new emerging pathogen.IMPORTANCECandida auris was first described in Japan in 2009 and has now been the cause of significant outbreaks across the globe. The high number of isolates that are resistant to one or more antifungals, as well as the high mortality rates from patients with bloodstream infections, has attracted the attention of the medical mycology, infectious disease, and public health communities to this pathogenic fungus. In the current work, we performed a broad multi-omics approach on two clinical isolates isolated in New York, the most affected area in the United States and found that the omic profile of C. auris differs significantly from C. albicans In addition to our insights into C. auris carbon utilization and lipid and protein content, we believe that the availability of these data will enhance our ability to combat this rapidly emerging pathogenic yeast.

Project description:Candida auris is an emerging fungal pathogen capable of causing invasive infections in humans. Since its first appearance around 1996, it has been isolated in countries spanning five continents. C. auris is a yeast that has the potential to cause outbreaks in hospitals, can survive in adverse conditions, including dry surfaces and high temperatures, and has been frequently misidentified by traditional methods. Furthermore, strains have been identified that are resistant to two and even all three of the main classes of antifungals currently in use. Several nuclear genome assemblies of C. auris have been published representing different clades and continents, yet until recently, the mitochondrial genomes (mtDNA chromosomes) of this species and the closely related species of C. haemulonii, C. duobushaemulonii, and C. pseudohaemulonii had not been analyzed in depth. We used reads from PacBio and Illumina sequencing to obtain a de novo reference assembly of the mitochondrial genome of the C. auris clade I isolate B8441 from Pakistan. This assembly has a total size of 28.2 kb and contains 13 core protein-coding genes, 25 tRNAs and the 12S and 16S ribosomal subunits. We then performed a comparative analysis by aligning Illumina reads of 129 other isolates from South Asia, Japan, South Africa, and South America with the B8441 reference. The clades of the phylogenetic tree we obtained from the aligned mtDNA sequences were consistent with those derived from the nuclear genome. The mitochondrial genome revealed a generally low genetic variation within clades, although the South Asian clade displayed two sub-branches including strains from both Pakistan and India. In particular, the 86 isolates from Colombia and Venezuela had mtDNA sequences that were all identical at the base level, i.e., a single conserved haplotype or mitochondrial background that exhibited characteristic differences from the Pakistan reference isolate B8441, such as a unique 25-nt insert that may affect function.

Dataset Information

Understanding Echinocandin Resistance in the Emerging Pathogen Candida auris.

Publications

Understanding Echinocandin Resistance in the Emerging Pathogen Candida auris.

Similar Datasets

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