Candida auris
1. Classification
Higher order taxa
Domain: Eukaryota; Kingdom: Fungi; Phylum: Ascomycota; Class: Saccharomycetes; Order: Saccharomycetales; Family: Metschnikowia Ceae; Genus: Candida; Species: Candida auris
2. Description and significance
Discovered in 2009, Candida Auris is a fungus that infiltrates the bloodstream and afflicts the central nervous system of the human body. Candida Auris particularly affects immunocompromised patients (Cortegani 2018). C. auris can be easily transmitted on a variety of surfaces including unsterilized medical equipment when used for multiple patients (Welsh 2018), as well as via one’s skin, rectum, akilla and stool (Cortegani 2019). C. auris infections are of clinical significance because it exhibits multilayer drug resistance leading to a high mortality rate (Cortegani 2018). Identification of C. auris infections is often difficult, as it is commonly misidentified as other Candida species. Multiple strains of this fungus exist, each developing independently on three different continents (Casadevall 2019). Due to its high levels of transmissibility, multidrug resistance, and mortality rates, C. auris is particularly dangerous to immunocompromised patients and is a growing area of research within the healthcare system.
3. Genome structure
Describe the size and content of the genome. How many chromosomes? Circular or linear? Other interesting features? What is known about its sequence?
4. Cell structure
Interesting features of cell structure. Can be combined with “metabolic processes”
5. Metabolic processes
Describe important sources of energy, electrons, and carbon (i.e. trophy) for the organism/organisms you are focusing on, as well as important molecules it/they synthesize(s).
6. Ecology
Habitat; symbiosis; contributions to the environment.
7. Pathology
C. Auris is commonly found in the bloodstream and once it has infiltrated the bloodstream, the fungi may easily be transferred through the body (Casadevall 2019). Candida auris infections lead to death every 1 in 3 patients (CDC). Although samples of C. Auris have been retrieved in patient’s urine and respiratory tract, it does not necessarily infect these areas in an active manner (CDC). Patients with comorbidities have an increased infection and mortality rate (CDC). Specifically in humans, C. Auris colonizes a patient’s skin, nose, ears, mouth, rectum or vagina (Jackson 2019). Identification can prove challenging with Candida auris. Appearance can be used to aid identification, but Candida auris is indistinguishable from other Candida species under a microscope (CDC). The CDC recommends that real-time PCR be used to identify Candida auris (CDC). For institutions lacking appropriate resources to produce a real-time PCR test, the agar media CHROMagar is the only conventional agar plate that allows for differentiation from common Candida species (CDC). MALDI-TOF mass spectrometry is the most accurate identification method, however, some databases do not allow for Candida auris identification. Additionally, MALDI-TOF is not a readily viable option in most clinical settings (CDC). C. auris infection outbreaks can prove challenging to control. Molecular methods of detection, such as MALDI-TOF, are required for official diagnosis of an infection of C. auris (CDC). C. auris infections can last for months and withstand common disinfectants and antifungal treatments (Sherry 2017). Consequently, preventing C. auris infection is of critical importance. In the case of infection, treatment with echinocandins, to which C. auris isolates have been shown to be susceptible to, is the suggested initial treatment, though no optimal treatment plan has been identified (Spivak 2018).
8. Current Research
Current research on C. auris is focused on further characterization of the molecular mechanisms that allow for multidrug resistance, as well as improved detection methods to distinguish it from other Candida species. Currently, the standard method for C. auris testing is RT-PCR which, while effective, is both time consuming and costly (Leach 2018). Recent developments, such as the production of single tube PCR methods, allow for fast, inexpensive detection that is more accessible and highly specific (Theill 2018). Numerous studies have been conducted with the goal of elucidating the mechanisms of multidrug resistance and potential treatments or preventions. Other studies have investigated whether existing therapies or known antifungal molecules that are not typically used for Candida infections may be effective in combating C. auris. One such instance of this is the antidepressant drug Sertraline. Treatment of C. auris with Sertraline in vitro was able to effectively inhibit growth and disrupt biofilm production (Gowri 2020). Similar growth inhibition and subsequent cell death was seen after treatment of C. auris with salivary histatin 5, a salivary peptide that provides one of the first lines of defense in the human innate immune system (Pathirana 2018). Such results provide the potential to develop more effective antifungal treatments and shed light on the mechanisms that make up the foundation of C. auris drug resistance. Although treatment of C. auris infections is critical, preventing the spread of this fungus in clinical settings is of equal importance. C. auris has been shown to spread easily on non-sterile surfaces; however, vaccination may reduce the risk of transmission. NDV-3A, a vaccine based on a cell surface protein of C. auris, was shown to reduce infection in mice models (Singh 2019). This vaccine was able to disrupt the biofilm produced by the fungus and aid in bolstering an immune response against infection (Singh 2019). In the absence of a vaccine, more efficient sterilization methods are being developed to reduce surface transmission of C. auris. A recent study shows that, under certain parameters, UV-C could be used to kill C. auris (De Groot 2019). Methods such as these may aid to limit the infections caused by C. auris.
9. References
It is required that you add at least five primary research articles (in same format as the sample reference below) that corresponds to the info that you added to this page. [Sample reference] Faller, A., and Schleifer, K. "Modified Oxidase and Benzidine Tests for Separation of Staphylococci from Micrococci". Journal of Clinical Microbiology. 1981. Volume 13. p. 1031-1035.
Edited by William Denton, student of Jennifer Bhatnagar for BI 311 General Microbiology, 2015, Boston University.
