Killing of Candida auris by UV-C: Importance of exposure time and distance

A correlative study of the genomic underpinning of virulence traits and drug tolerance of Candida auris

Candida auris is an opportunistic fungal pathogen with high mortality rates which presents a clear threat to public health. The risk of C. auris infection is high because it can colonize the body, resist antifungal treatment, and evade the immune system. The genetic mechanisms for these traits are not well known. Identifying them could lead to new targets for new treatments. To this end, we present an analysis of the genetics and gene expression patterns of C. auris carbon metabolism, drug resistance, and macrophage interaction. We chose to study two C. auris isolates simultaneously, one drug sensitive (B11220 from Clade II) and one drug resistant (B11221 from Clade III). Comparing the genomes, we confirm the previously reported finding that B11220 was missing a 12.8 kb region on chromosome VI. This region contains a gene cluster encoding proteins related to alternative sugar utilization. We show that B11221, which has the gene cluster, readily assimilates and utilizes D-galactose and L-rhamnose as compared to B11220, which harbors the deletion. B11221 exhibits increased adherence and drug resistance compared to B11220 when grown in these sugars. Transcriptomic analysis of both isolates grown on glucose or galactose showed that the gene cluster was upregulated when grown on D-galactose. These findings reinforce growing evidence of a link between metabolism and drug tolerance. B11221 resists phagocytosis by macrophages and exhibits decreased β-1,3-glucan exposure, a key determinant that allows Candida to evade the host immune system, as compared to B11220. In a transcriptomic analysis of both isolates co-cultured with macrophages, we find upregulation of genes associated with transport and transcription factors in B11221. Our studies show a positive correlation between membrane composition and immune evasion, alternate sugar utilization, and drug tolerance in C. auris.

The laboratory investigation, management, and infection prevention and control of Candida auris: a narrative review to inform the 2024 national guidance update in England

The emergent fungal pathogen Candida auris is increasingly recognised as an important cause of healthcare-associated infections globally. It is highly transmissible, adaptable, and persistent, resulting in an organism with significant outbreak potential that risks devastating consequences. Progress in the ability to identify C. auris in clinical specimens is encouraging, but laboratory diagnostic capacity and surveillance systems are lacking in many countries. Intrinsic resistance to commonly used antifungals, combined with the ability to rapidly acquire resistance to therapy, substantially restricts treatment options and novel agents are desperately needed. Despite this, outbreaks can be interrupted, and mortality avoided or minimised, through the application of rigorous infection prevention and control measures with an increasing evidence base. This review provides an update on epidemiology, the impact of the COVID-19 pandemic, risk factors, identification and typing, resistance profiles, treatment, detection of colonisation, and infection prevention and control measures for C. auris. This review has informed a planned 2024 update to the United Kingdom Health Security Agency (UKHSA) guidance on the laboratory investigation, management, and infection prevention and control of Candida auris. A multidisciplinary response is needed to control C. auris transmission in a healthcare setting and should emphasise outbreak preparedness and response, rapid contact tracing and isolation or cohorting of patients and staff, strict hand hygiene and other infection prevention and control measures, dedicated or single-use equipment, appropriate disinfection, and effective communication concerning patient transfers and discharge.

Enhancing Candida auris Surveillance in High-Risk Settings by Implementing a High-Throughput Molecular Assay on the Hologic Fusion Open Access Platform

Candida auris, a resilient pathogenic yeast with frequent multidrug resistance, presents a persistent challenge in healthcare settings. The timely identification of C. auris is crucial for infection control and prevention, especially in facilities facing unique hurdles, such as our institution, which serves four major hospitals and approximately 80% of the Texas inmate population. Understaffing, communal living, and financial constraints exacerbate infection control issues. To address common staff shortages, streamline testing services, and enhance testing efficiency, there was a pressing need for rapid and high-throughput detection of C. auris. This study presents the validation and utility of an assay implemented on the Hologic Fusion Open Access platform using samples collected from high-risk patients' axilla and groin areas, as well as environmental swab samples from patient rooms. Our assay complemented efforts to control C. auris outbreaks within our healthcare system, providing valuable insights into its presence within surveillance samples. This assay demonstrated the value of high-throughput molecular detection platforms in challenging healthcare environments by aiding infection preventionists in containing the spread of C. auris and preventing nosocomial infections. Our research contributes essential data on the suitability and performance of the Hologic Fusion Open Access platform for C. auris detection. These findings hold significant implications for enhancing surveillance and control measures in high-risk settings, making a significant impact on the field of infection control and prevention.

The many faces of Candida auris: Phenotypic and strain variation in an emerging pathogen

Candida auris is an emerging fungal pathogen with unusual evolutionary history-there are multiple distinct phylogeographic clades showing a near simultaneous transition from a currently unknown reservoir to nosocomial pathogen. Each of these clades has experienced different selective pressures over time, likely resulting in selection for genotypes with differential fitness or phenotypic consequences when introduced to new environments. We also observe diversification within clades, providing additional opportunities for phenotypic differences. These differences can have large impacts on pathogenic potential, drug resistance profile, evolutionary trajectory, and transmissibility. In recent years, there have been significant advances in our understanding of strain-specific behavior in other microbes, including bacterial and fungal pathogens, and we have an opportunity to take this strain variation into account when describing aspects of C. auris biology. Here, we critically review the literature to gain insight into differences at both the strain and clade levels in C. auris, focusing on phenotypes associated with clinical disease or transmission. Our goal is to integrate clinical and epidemiological perspectives with molecular perspectives in a way that would be valuable for both audiences. Identifying differences between strains and understanding which phenotypes are strain specific will be crucial for understanding this emerging pathogen, and an important caveat when describing the analysis of a singular isolate.

Skin and hard surface disinfection against Candida auris - What we know today

Candida auris has emerged as a global healthcare threat, displaying resistance to important healthcare antifungal therapies. Infection prevention and control protocols have become paramount in reducing transmission of C. auris in healthcare, of which cleaning and disinfection plays an important role. Candida albicans is used as a surrogate yeast for yeasticidal claims of disinfection products, but reports have been made that sensitivity to disinfectants by C. auris differs from its surrogate. In this review, we aimed to compile the information reported for products used for skin and hard surface disinfection against C. auris in its planktonic or biofilm form. A comparison was made with other Candida species, and information were gathered from laboratory studies and observations made in healthcare settings.

Ultraviolet-C mediated inactivation of Candida auris, a rapid emerging health threat

Health care-associated infections, particularly those caused by multidrug-resistant organisms (MDROs), pose significant challenges to patient safety. Candida auris (C auris), an emerging MDRO fungus, has been acknowledged as an urgent threat by the Centers for Disease Control and Prevention due to its high mortality and difficulty in prevention, diagnosis, and treatment. In this study, we investigated the efficacy of 254 nm ultraviolet-C light (UV-C) in inactivating C auris on hard surfaces. A mobile UV-C tower equipped with high-performance bulbs was used, and within 7 minutes of continuous exposure, ≥99.97% (≥3.86 log10) inactivation of C auris was achieved in a patient-room-sized test chamber. Our findings suggest that UV-C can serve as an adjunct infection control measure for preventing C auris and other MDRO Health care-associated infections in health care settings. Implementation of UV-C disinfection protocols can contribute to enhanced patient safety and combat the growing threat of MDRO pathogens.

Long-range air dispersion of Candida auris in a cardiothoracic unit outbreak in Hong Kong

BACKGROUND

Nosocomial outbreaks of Candida auris, a multidrug-resistant fungus, are increasingly reported worldwide; the mode of transmission has usually been reported to be via direct contact. Some studies previously suggested potential short-distance air dispersal during high-turbulence activities, but evidence on long-range air dispersal remains scarce.

AIM

To describe a C. auris nosocomial outbreak involving two wards (H7, 5E) in two local hospitals.

METHODS

Samples were taken from patients, ward surfaces (frequently touched items and non-reachable surfaces) while settle plates were used for passive air sampling to investigate possible contributions by direct contact and air dispersal. Epidemiological and phylogenetic analyses were also performed on the C. auris isolates from this outbreak.

FINDINGS

Eighteen patients were confirmed to have asymptomatic C. auris skin colonization. C. auris was expectedly identified in samplings from frequently touched ward items but was also isolated in two samples from ceiling supply air grilles which were 2.4 m high and inaccessible by patients. Moreover, one sample from a corridor return air grille as far as 9.8 m away from the C. auris cohort area was also positive. Two passive air samplings were positive, including one from a cubicle with no confirmed cases for four days, suggesting possible air dispersal of C. auris. Whole-genome sequencing confirmed clonality of air, environment, and patients' isolates.

CONCLUSION

This is the first study to demonstrate potential long-range air dispersal of C. auris in an open-cubicle ward setting. Ventilation precautions and decontamination of out-of-reach high-level surfaces should be considered in C. auris outbreak management.

Ultraviolet-C light at 222 nm has a high disinfecting spectrum in environments contaminated by infectious pathogens, including SARS-CoV-2

Ultraviolet light (UV) acts as a powerful disinfectant and can prevent contamination of personal hygiene from various contaminated environments. The 222-nm wavelength of UV-C has a highly effective sterilization activity and is safer than 275-nm UV-C. We investigated the irradiation efficacy of 222-nm UV-C against contaminating bacteria and viruses in liquid and fabric environments. We conducted colony-forming unit assays to determine the number of viable cells and a 50% tissue culture infectious dose assay to evaluate the virus titration. A minimum dose of 27 mJ/cm2 of 222-nm UV-C was required for >95% germicidal activity for gram-negative and -positive bacteria. A 25.1 mJ/cm2 dose could ensure >95% virucidal activity against low-pathogenic avian influenza virus and severe acute respiratory syndrome coronavirus (SARS-CoV-2). In addition, this energy dose of 222-nm UV-C effectively inactivated SARS-CoV-2 variants, Delta and Omicron. These results provide valuable information on the disinfection efficiency of 222-nm UV-C in bacterial and virus-contaminated environments and can also develop into a powerful tool for individual hygiene.

Emerging infectious diseases, focus on infection prevention, environmental survival and germicide susceptibility: SARS-CoV-2, Mpox, and Candida auris

BACKGROUND

New and emerging infectious diseases continue to represent a public health threat. Emerging infectious disease threats include pathogens increasing in range (eg, Mpox), zoonotic microbes jumping species lines to cause sustained infections in humans via person-to-person transmission (SARS-CoV-2) and multidrug-resistant pathogens (eg, Candida auris).

MATERIALS AND METHODS

We searched the published English literature and reviewed the selected articles on SARS-CoV-2, Mpox, and Candida auris with a focus on environmental survival, contamination of the patient's hospital environment, susceptibility of the pathogen to antiseptics and disinfectants and infection prevention recommendations.

RESULTS

All three pathogens (ie, SARS-CoV-2, Mpox, and Candida auris) can survive on surfaces for minutes to hours and for Mpox and C auris for days. Currently available antiseptics (eg, 70%-90% alcohol hand hygiene products) are active against SARS-CoV-2, Mpox and C auris. The U.S Environmental Protection Agency provides separate lists of surface disinfectants active against SARS-CoV-2, Mpox, and C auris.

DISCUSSION

The risk of environment-to-patient transmission of SARS-CoV-2, Mpox and Candida auris, is very low, low-moderate and high, respectively. In the absence of appropriate patient isolation and use of personal protection equipment, the risk of patient-to-health care provider transmission of SARS-CoV-2, Mpox, and C auris is high, moderate and low, respectively.

CONCLUSIONS

Appropriate patient isolation, use of personal protective equipment by health care personnel, hand hygiene, and surface disinfection can protect patients and health care personnel from acquiring SARS-CoV-2, Mpox, and C auris from infected patients.

Microbe-loaded bioink designed to support therapeutic yeast growth

Live biotherapeutic products (LBPs) are an emerging class of therapeutics comprised of engineered living organisms such as bacteria or yeast. Bioprinting with living materials has now become possible using modern three-dimensional (3D) printing strategies. While there has been significant progress in bioprinting cells, bioprinting LBPs, specifically yeast, remains in its infancy and has not been optimized. Yeasts are a promising platform to develop into protein biofactories because they (1) grow rapidly, (2) are easy to engineer and manufacture, and (3) are inexpensive to produce. Here we developed an optimized method for loading yeast into hydrogel patches using digital light processing (DLP) 3D printing. We assessed the effects of patch geometry, bioink composition, and yeast concentration on yeast viability, patch stability, and protein release, and in doing so developed a patch formulation capable of supporting yeast growth and sustained protein release for at least ten days.

Strategies to Prevent Transmission of Candida auris in Healthcare Settings

Purpose of Review

Candida auris, a recently recognized yeast pathogen, has become a major public health threat due to the problems associated with its accurate identification, intrinsic and acquired resistance to antifungal drugs, and its potential to easily contaminate the environment causing clonal outbreaks in healthcare facilities. These outbreaks are associated with high mortality rates particularly among older patients with multiple comorbidities under intensive care settings. The purpose of this review is to highlight strategies that are being adapted to prevent transmission of C. auris in healthcare settings.

Recent Findings

Colonized patients shed C. auris into their environment which contaminates surrounding equipment. It resists elimination even by robust decontamination procedures and is easily transmitted to new patients during close contact resulting in outbreaks. Efforts are being made to rapidly identify C. auris-infected/C. auris-colonized patients, to determine its susceptibility to antifungals, and to perform effective cleaning and decontamination of the environment and isolation of colonized patients to prevent further transmission.

Summary

Rapid and accurate identification of hospitalized patients infected/colonized with C. auris, rapid detection of its susceptibility patterns, and appropriate use of infection control measures can help to contain the spread of this highly pathogenic yeast in healthcare settings and prevent/control outbreaks.

The in situ efficacy of whole room disinfection devices: a literature review with practical recommendations for implementation

BACKGROUND

Terminal cleaning and disinfection of hospital patient rooms must be performed after discharge of a patient with a multidrug resistant micro-organism to eliminate pathogens from the environment. Terminal disinfection is often performed manually, which is prone to human errors and therefore poses an increased infection risk for the next patients. Automated whole room disinfection (WRD) replaces or adds on to the manual process of disinfection and can contribute to the quality of terminal disinfection. While the in vitro efficacy of WRD devices has been extensively investigated and reviewed, little is known about the in situ efficacy in a real-life hospital setting. In this review, we summarize available literature on the in situ efficacy of WRD devices in a hospital setting and compare findings to the in vitro efficacy of WRD devices. Moreover, we offer practical recommendations for the implementation of WRD devices.

METHODS

The in situ efficacy was summarized for four commonly used types of WRD devices: aerosolized hydrogen peroxide, H₂O₂ vapour, ultraviolet C and pulsed xenon ultraviolet. The in situ efficacy was based on environmental and clinical outcome measures. A systematic literature search was performed in PubMed in September 2021 to identify available literature. For each disinfection system, we summarized the available devices, practical information, in vitro efficacy and in situ efficacy.

RESULTS

In total, 54 articles were included. Articles reporting environmental outcomes of WRD devices had large variation in methodology, reported outcome measures, preparation of the patient room prior to environmental sampling, the location of sampling within the room and the moment of sampling. For the clinical outcome measures, all included articles reported the infection rate. Overall, these studies consistently showed that automated disinfection using any of the four types of WRD is effective in reducing environmental and clinical outcomes.

CONCLUSION

Despite the large variation in the included studies, the four automated WRD systems are effective in reducing the amount of pathogens present in a hospital environment, which was also in line with conclusions from in vitro studies. Therefore, the assessment of what WRD device would be most suitable in a specific healthcare setting mostly depends on practical considerations.

Investigation of effect of cold plasma on microbial load and physicochemical properties of ready-to-eat sliced chicken sausage

Sausage may be contaminated with spoilage microorganisms during the processing after cooking and during the chilling process. Non-thermal decontamination such as cold plasma (CP) can be used to prevent the growth of spoilage microorganisms in sausage after packaging. The objective of this study was to investigate the effects of CP on sliced chicken sausage during 60 days of storage. The sausages were divided into three groups: negative control, ultraviolet (UV)-radiated (positive control for 200 and 400 s), plasma (power of 30 and 70 w for 200 and 400 s). The microbial load, pH, color, peroxide value (PV), and textural parameters of the sausages were compared with those of the negative and positive controls. According to the results, total count decreased significantly (p < 0.05) about 1.87 log CFU/g after 400 s of the CP treatment and at the end of storage at 70 w. CP reduced the lightness (L*) and increased redness (a*) more than the UV rays. The PV more increased by UV rather than by plasma. There were no significant changes in pH value and textural parameters after the CP and UV treatments. Although CP more affected some of the physicochemical properties, compared with UV, CP was shown to efficiently inhibit the rapid growth of microorganisms, resulting in a longer shelf-life.

Emerging strategies for environmental decontamination of the nosocomial fungal pathogen Candida auris

Candida auris is a recently emerged multidrug-resistant fungal pathogen that causes life-threatening infections to the human population worldwide. Recent rampant outbreaks of C. auris in coronavirus disease 2019 (COVID-19) patients, together with outbreaks in over 45 countries, highlight its threat to patients and healthcare economies. Unlike other pathogenic Candida species, C. auris is capable of surviving in abiotic surfaces of healthcare facilities for prolonged periods, leading to increased risk of transmission within nosocomial settings. C. auris is resistant to multiple classes of antifungal agents, forms dry biofilms and transmits independently to regional epicentres, making its eradication from nosocomial environment arduous. The lack of strategies for environmental decontamination of C. auris from nosocomial settings is evident from the generic guidance and recommendations provided by leading global healthcare bodies. Therefore, this minireview discusses the current guidelines for environmental decontamination of C. auris and compounds and strategies currently under investigation for potential future use. While established guidelines recommend the use of products mainly consisting of sodium hypochlorite and hydrogen peroxide, initial works have been reported on the promising anti-C. auris properties of various other compounds and some biocompatible alternatives. Further validation of these approaches, coupled up with environmentally friendly decontamination protocols, are warranted to achieve superior elimination of C. auris from healthcare settings.

Shining light on multi-drug resistant Candida auris: Ultraviolet-C disinfection, wavelength sensitivity, and prevention of biofilm formation of an emerging yeast pathogen

Candida auris is an emerging fungal superbug of worldwide interest. It is associated with high mortality rates and exhibits increased resistance to antifungals. Ultraviolet subtype C (UVC) light can be used to disinfect surfaces to mitigate its spread. The objectives of this study were (1) To investigate UVC disinfection performances and wavelength sensitivity of C. auris. (2) To evaluate the UVC dose required for the prevention of biofilm formation on stainless-steel, plastic (polystyrene), and poly-cotton fabric surfaces. C. auris was grown following standard procedures. The study utilized six different UVC LED arrays with wavelengths between 252 and 280 nm. Arrays were set at similar intensities, to obtain doses of 5-40 mJ cm-2 and similar irradiation time. Disinfection performance for each array was determined using log reduction value (LRV) and percentage reduction by comparing the controls against the irradiated treatments. Evaluation of the ability of 267 nm UVC LEDs to prevent C. auris biofilm formation was investigated using stainless-steel, plastic coupons, and poly-cotton fabric. Peak sensitivity to UVC disinfection was between 267 and 270 nm. With 20 mJ cm-2 , the study obtained ≥LRV3. On stainless-steel coupons, 30 mJ cm-2 was sufficient to prevent biofilm formation, while on plastic, this required 10 mJ cm-2 . A dose of 60 mJ cm-2 reduced biofilms on poly-cotton fabric significantly (R2  = 0.9750, p = 0.0002). The study may allow for the design and implementation of disinfection systems.

Acaricidal efficacy of ultraviolet-C irradiation of Tetranychus urticae adults and eggs using a pulsed krypton fluoride excimer laser

BACKGROUND

Pulsed ultraviolet (UV)-C light sources, such as excimer lasers, are used in emerging non-thermal food-decontamination methods and also have high potential for use in a wide range of microbial decontamination applications. The acaricidal effect of an experimental UV-C irradiation device was assessed using female adults and eggs of a model organism, the two-spotted spider mite Tetranychus urticae.

METHODS

UV-C light was generated by a pulsed krypton fluoride excimer laser operating at 248-nm emission wavelength. The pulse energy and pulse repetition rate were 5 mJ and up to 100 Hz, respectively. The distance from the light source to the target was 150 mm; the target surface area was 2.16 cm2. The exposure time for the mites and fresh eggs varied from 1 to 4 min at 5-300 mW, which corresponded to UV doses of 5-80 kJ/m2. Post-irradiation acaricidal effects (mite mortality) were assessed immediately and also measured at 24 h. The effects of UV-C irradiation on the hatchability of eggs were observed daily for up to 12 days post-irradiation.

RESULTS

The mortality of mites at 5 and 40 kJ/m2 was 26% and 92%, respectively. Mite mortality reached 98% at 80 kJ/m2. The effect of exposure duration on mortality was minimal. The effect of irradiation on egg hatchability was even more significant than that on adult mite mortality, i.e. about 100% egg mortality at an accumulated dose of as little as 5 kJ/m2 for each exposure time.

CONCLUSIONS

A high rate of mite mortality and lethal egg damage were observed after less than 1 min of exposure to 5 mJ UV-C pulsed irradiation at 60 Hz. Pending further developments (such as beam steering, beam shaping and miniaturisation) and feasibility studies (such as testing with mites in real-life situations), the reported results and characteristics of the UV-C generator (modulation of energy output and adaptability to varying spot sizes) open up the use of this technology for a vast field of acaricidal applications that require long-range radiation.

Public health issues with Candida auris in COVID-19 patients

The ongoing pandemic of coronavirus disease 2019 (COVID‐19) has overwhelmed a number of medical facilities as well as a few entire health‐care systems. A novel issue co‐incident with the expeditious deployment of specialty care units for COVID‐19 inpatients is the worldwide epidemic of Candida auris infections. Since its first identification and classification in Japan in 2009, it has spread globally. This threat was predicted as C. auris has a high mortality rate, cryptic fomite spread, frequent misidentification since conventional methods do not detect it, and multidrug‐resistance. Since the April 2020 warning at the start of the COVID‐19 pandemic in the United States, C. auris has been delineated as an increasingly consequential source of significant nosocomial infections, emphasizing the added hazard of C. auris to COVID‐19 inpatients, particularly those in intensive care units.

Candida auris was a worldwide nosocomial epidemic prior to COVID‐19; it remains so!

This 21st century worldwide fungal epidemic complicates the COVID‐19 pandemic to jointly menace mankind

C. auris is multi‐drug resistant, requires expensive mass spectrometry equipment to diagnose, and has a high mortality rate in intensive care units

This nosocomial infection may persist on dry linen, sheets, floors, cell phones, and medical equipment for weeks

We propose a policy that documents the presence or absence of this invasive Candidal species in intensive care units during this COVID‐19 pandemic to aggressively eliminate it.

Diagnostic Allele-Specific PCR for the Identification of Candida auris Clades

Candida auris is an opportunistic pathogenic yeast that emerged worldwide during the past decade. This fungal pathogen poses a significant public health threat due to common multidrug resistance (MDR), alarming hospital outbreaks, and frequent misidentification. Genomic analyses have identified five distinct clades that are linked to five geographic areas of origin and characterized by differences in several phenotypic traits such as virulence and drug resistance. Typing of C. auris strains and the identification of clades can be a powerful tool in molecular epidemiology and might be of clinical importance by estimating outbreak and MDR potential. As C. auris has caused global outbreaks, including in low-income countries, typing C. auris strains quickly and inexpensively is highly valuable. We report five allele-specific polymerase chain reaction (AS-PCR) assays for the identification of C. auris and each of the five described clades of C. auris based on conserved mutations in the internal transcribed spacer (ITS) rDNA region and a clade-specific gene cluster. This PCR method provides a fast, cheap, sequencing-free diagnostic tool for the identification of C. auris, C. auris clades, and potentially, the discovery of new clades.

Performance study of a sterilization box using a combination of heat and ultraviolet light irradiation for the prevention of COVID-19

SARS-CoV-2 virus and other pathogenic microbes are transmitted to the environment through contacting surfaces, which need to be sterilized for the prevention of COVID-19 and related diseases. In this study, a prototype of a cost-effective sterilization box is developed to disinfect small items. The box utilizes ultra violet (UV) radiation with heat. For performance assessment, two studies were performed. First, IgG (glycoprotein, a model protein similar to that of spike glycoprotein of SARS-COV-2) was incubated under UV and heat sterilization. An incubation with UV at 70 °C for 15 min was found to be effective in unfolding and aggregation of the protein. At optimized condition, the hydrodynamic size of the protein increased to ~171 nm from ~5 nm of the native protein. Similarly, the OD₂₈₀ values also increased from 0.17 to 0.78 indicating the exposure of more aromatic moieties and unfolding of the protein. The unfolding and aggregation of the protein were further confirmed by the intrinsic fluorescence measurement and FTIR studies, showing a 70% increase in the β-sheets and a 22% decrease in the α-helixes of the protein. The designed box was effective in damaging the protein's native structure indicating the effective inactivation of the SARS-COV-2. Furthermore, the incubation at 70 °C for 15 min inside the chamber resulted in 100% antibacterial efficacy for the clinically relevant E.coli bacteria as well as for bacteria collected from daily use items. It is the first detailed performance study on the efficacy of using UV irradiation and heat together for disinfection from virus and bacteria.

The use of a UV-C disinfection robot in the routine cleaning process: a field study in an Academic hospital

Background

Environmental surface decontamination is a crucial tool to prevent the spread of infections in hospitals. However, manual cleaning and disinfection may be insufficient to eliminate pathogens from contaminated surfaces. Ultraviolet-C (UV-C) irradiation deploying autonomous disinfection devices, i.e. robots, are increasingly advertised to complement standard decontamination procedures with concurrent reduction of time and workload. Although the principle of UV-C based disinfection is proven, little is known about the operational details of UV-C disinfection delivered by robots. To explore the impact of a UV-C disinfection robot in the clinical setting, we investigated its usability and the effectiveness as an add-on to standard environmental cleaning and disinfection. Additionally, its effect on Candida auris, a yeast pathogen resistant to antifungals and disinfectants, was studied.

Methods

After setting the parameters “surface distance” and “exposure time” for each area as given by the manufacturer, the robot moved autonomously and emitted UV-C irradiation in the waiting areas of two hospital outpatient clinics after routine cleaning and/or disinfection. To quantify the efficacy of the robotic UV-C disinfection, we obtained cultures from defined sampling sites in these areas at baseline, after manual cleaning/disinfection and after the use of the robot. Four different C. auris strains at two concentrations and either in a lag or in a stationary growth phase were placed in these areas and exposed to UV-C disinfection as well.

Results

The UV-C irradiation significantly reduced the microbial growth on the surfaces after manual cleaning and disinfection. C. auris growth in the lag phase was inhibited by the UV-C irradiation but not in the presence of the rim shadows. The effects on C. auris in the stationary phase were differential, but overall C. auris strains were not effectively killed by the standard UV-C disinfection cycle. Regarding usability, the robot’s interface was not intuitive, requiring advanced technical knowledge or intensive training prior to its use. Additionally, the robot required interventions by the technical operator during the disinfection process, e.g. stopping due to unforeseen minor dislocation of items during the clinical service or due to moving individuals, making it a delicate high-tech device but not yet ready for the autonomous use in the clinical routine.

Conclusions

Presently, the UV-C robot tested in this study is not ready to be integrated in the environmental cleaning and disinfection procedures in our hospital. The single standard disinfection UV-C irradiation cycle is not sufficient to inactivate pathogens with augmented environmental resilience, e.g. C. auris, particularly when microbial loads are high.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13756-021-00945-4.

Inactivation of Candida auris and Candida albicans by ultraviolet-C

We evaluated the ability of an ultraviolet-C (UV-C) room decontamination device to kill Candida auris and C. albicans. With an organic challenge (fetal calf serum), the UV-C device demonstrated the following log10 reductions for C. auris of 4.57 and for C. albicans of 5.26 with direct line of sight, and log10 reductions for C. auris of 2.41 and for C. ablicans of 3.96 with indirect line of sight.

Efficacy of relatively low-cost ultraviolet-C light devices against Candida auris

BACKGROUND

Ultraviolet-C (UV-C) light devices could be useful to reduce environmental contamination with Candida auris. However, variable susceptibility of C. auris strains to UV-C has been reported, and the high cost of many devices limits their use in resource-limited settings.

OBJECTIVE

To evaluate the efficacy of relatively low-cost (<$15,000 purchase price) UV-C devices against C. auris strains from the 4 major phylogenetic clades.

METHODS

A modification of the American Society for Testing and Materials (ASTM) standard quantitative disk carrier test method (ASTM E 2197) was used to examine and compare the effectiveness of UV-C devices against C. auris, methicillin-resistant Staphylococcus aureus (MRSA), and bacteriophage Phi6. Reductions of 3 log10 were considered effective. UV-C irradiance measurements and colorimetric indicators were used to assess UV-C output.

RESULTS

Of 8 relatively low-cost UV-C devices, 6 met the criteria for effective decontamination of C. auris isolates from clades I and II, MRSA, and bacteriophage Phi6, including 3 room decontamination devices and 3 UV-C box devices. Candida auris isolates from clades III and IV were less susceptible to UV-C than clade I and II isolates; 1 relatively low-cost room decontamination device and 2 enclosed box devices met the criteria for effective decontamination of clade III and IV isolates. UV-C irradiance measurements and colorimetric indicator results were consistent with microorganism reductions.

CONCLUSIONS

Some relatively low-cost UV-C light technologies are effective against C. auris, including isolates from clades III and IV with reduced UV-C susceptibility. Studies are needed to evaluate the effectiveness of UV-C devices in clinical settings.

Clade-specific chromosomal rearrangements and loss of subtelomeric adhesins in Candida auris

Candida auris is an emerging fungal pathogen of rising concern due to global spread, the ability to cause healthcare-associated outbreaks, and antifungal resistance. Genomic analyses revealed that early contemporaneously detected cases of C. auris were geographically stratified into four major clades. While Clades I, III, and IV are responsible for ongoing outbreaks of invasive and multidrug-resistant infections, Clade II, also termed the East Asian clade, consists primarily of cases of ear infection, is often susceptible to all antifungal drugs, and has not been associated with outbreaks. Here, we generate chromosome-level assemblies of twelve isolates representing the phylogenetic breadth of these four clades and the only isolate described to date from Clade V. This Clade V genome is highly syntenic with those of Clades I, III, and IV, although the sequence is highly divergent from the other clades. Clade II genomes appear highly rearranged, with translocations occurring near GC-poor regions, and large subtelomeric deletions in most chromosomes, resulting in a substantially different karyotype. Rearrangements and deletion lengths vary across Clade II isolates, including two from a single patient, supporting ongoing genome instability. Deleted subtelomeric regions are enriched in Hyr/Iff-like cell-surface proteins, novel candidate cell wall proteins, and an ALS-like adhesin. Cell wall proteins from these families and other drug-related genes show clade-specific signatures of selection in Clades I, III, and IV. Subtelomeric dynamics and the conservation of cell surface proteins in the clades responsible for global outbreaks causing invasive infections suggest an explanation for the different phenotypes observed between clades.

Candida auris: A Quick Review on Identification, Current Treatments, and Challenges

Candida auris is a novel and major fungal pathogen that has triggered several outbreaks in the last decade. The few drugs available to treat fungal diseases, the fact that this yeast has a high rate of multidrug resistance and the occurrence of misleading identifications, and the ability of forming biofilms (naturally more resistant to drugs) has made treatments of C. auris infections highly difficult. This review intends to quickly illustrate the main issues in C. auris identification, available treatments and the associated mechanisms of resistance, and the novel and alternative treatment and drugs (natural and synthetic) that have been recently reported.

Candida auris: Epidemiology, Diagnosis, Pathogenesis, Antifungal Susceptibility, and Infection Control Measures to Combat the Spread of Infections in Healthcare Facilities

Candida auris, a recently recognized, often multidrug-resistant yeast, has become a significant fungal pathogen due to its ability to cause invasive infections and outbreaks in healthcare facilities which have been difficult to control and treat. The extraordinary abilities of C. auris to easily contaminate the environment around colonized patients and persist for long periods have recently resulted in major outbreaks in many countries. C. auris resists elimination by robust cleaning and other decontamination procedures, likely due to the formation of 'dry' biofilms. Susceptible hospitalized patients, particularly those with multiple comorbidities in intensive care settings, acquire C. auris rather easily from close contact with C. auris-infected patients, their environment, or the equipment used on colonized patients, often with fatal consequences. This review highlights the lessons learned from recent studies on the epidemiology, diagnosis, pathogenesis, susceptibility, and molecular basis of resistance to antifungal drugs and infection control measures to combat the spread of C. auris infections in healthcare facilities. Particular emphasis is given to interventions aiming to prevent new infections in healthcare facilities, including the screening of susceptible patients for colonization; the cleaning and decontamination of the environment, equipment, and colonized patients; and successful approaches to identify and treat infected patients, particularly during outbreaks.

Promising Drug Candidates and New Strategies for Fighting against the Emerging Superbug Candida auris

Invasive fungal infections represent an expanding threat to public health. During the past decade, a paradigm shift of candidiasis from Candida albicans to non-albicans Candida species has fundamentally increased with the advent of Candida auris. C. auris was identified in 2009 and is now recognized as an emerging species of concern and underscores the urgent need for novel drug development strategies. In this review, we discuss the genomic epidemiology and the main virulence factors of C. auris. We also focus on the different new strategies and results obtained during the past decade in the field of antifungal design against this emerging C. auris pathogen yeast, based on a medicinal chemist point of view. Critical analyses of chemical features and physicochemical descriptors will be carried out along with the description of reported strategies.

Ultraviolet disinfection robots to improve hospital cleaning: Real promise or just a gimmick?

The global COVID-19 pandemic due to the novel coronavirus SARS-CoV-2 has challenged the availability of traditional surface disinfectants. It has also stimulated the production of ultraviolet-disinfection robots by companies and institutions. These robots are increasingly advocated as a simple solution for the immediate disinfection of rooms and spaces of all surfaces in one process and as such they seem attractive to hospital management, also because of automation and apparent cost savings by reducing cleaning staff. Yet, there true potential in the hospital setting needs to be carefully evaluated. Presently, disinfection robots do not replace routine (manual) cleaning but may complement it. Further design adjustments of hospitals and devices are needed to overcome the issue of shadowing and free the movement of robots in the hospital environment. They might in the future provide validated, reproducible and documented disinfection processes. Further technical developments and clinical trials in a variety of hospitals are warranted to overcome the current limitations and to find ways to integrate this novel technology in to the hospitals of to-day and the future.

Evaluation of a portable Ultraviolet C (UV-C) device for hospital surface decontamination

Background

Surface decontamination of hospital environments is essential to ensure the safety of health professionals and patients. This process is usually performed through active chemicals substances with high toxicity, and new decontamination technologies that do not leave residues have been currently used, such as UV-C light. Thus, the objective of the present study is to evaluate the effectiveness of a portable UV-C light device on the viability of standard pathogenic strains and other microorganisms isolated from different surfaces of a public health hospital.

Methods

In vitro decontamination was performed by applying Biosept Home© UV-C to Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, Salmonella enterica and Candida albicans. In real conditions, the application was made on different surfaces of a hospital. The device used in the experiment haa a 254 nm UV-C light and a radiation intensity of 45.6 mW/cm² over a distance of 1 cm from the surfaces. The light dose was 0.912 J/cm² for 20 s of application in both conditions (in vitro and hospital).

Results

After in vitro decontamination with UV-C light no bacterial growth was observed, demonstrating 100 % of bacterial inactivation under the conditions tested. Additionally, there was a reduction of approximately 4 logs for the yeast C. albicans. In all hospital surfaces, the number of colonies of microorganisms was significantly reduced after the procedure.

Conclusion

The results suggest that Biosept Home© UV-C is efficient and constitutes a promosing intervention for disinfection protocols in hospitals and clinics.

Environmental Disinfection of a Dental Clinic during the Covid-19 Pandemic: A Narrative Insight

BACKGROUND

The control of biological hazard risk in health care and dental clinic environments represents a critical point in relation to the Covid-19 infection outbreak and international public health emergency. The purpose of the present review was to evaluate the scientific literature on the no-touch disinfection procedures in dental clinics aiming to limit transmission via airborne particles or fomites using no-touch procedures for environmental decontamination of dental clinics.

METHODS

An electronic database literature search was performed to retrieve research papers about Covid-19 and no-touch disinfection topics including full-length articles, editorials, commentaries, and outbreak studies. A total of 86 papers were retrieved by the electronic research.

RESULTS

No clinical article about the decontamination of a dental clinic during the Covid-19 pandemic was detected. About the topic of hospital decontamination, we found different no-touch disinfection procedures used in hospital against highly resistant organisms, but no data were found in the search for such procedures with respect to SARS-CoV-2: (1) aerosolized hydrogen peroxide, (2) H2O2 vapor, (3) ultraviolet C light, (4) pulsed xenon, and (5) gaseous ozone. One paper was retrieved concerning SARS-CoV-2; 32 documents focused on SARS and MERS. The cleaning and disinfection protocol of health care and dental clinic environment surfaces are essential elements of infection prevention programs, especially during the SARS-CoV-2 pandemic.

CONCLUSION

The decontamination technique that best suits the needs of the dental clinic is peroxide and hypochlorous which can be sprayed via a device at high turbine speed with the ability of producing small aerosol particles, recommendable also for their low cost.

Clade-specific variation in susceptibility of Candida auris to broad-spectrum ultraviolet C light (UV-C)

Background:

Candida auris is an emerging and often multidrug-resistant fungal pathogen with an exceptional ability to persist on hospital surfaces. These surfaces can act as a potential source of transmission. Therefore, effective disinfection strategies are urgently needed. We investigated the efficacy of ultraviolet C light (UV-C) disinfection for C. auris isolates belonging to 4 different clades.

Methods:

In vitro testing of C. auris isolates was conducted using 10⁶ colony-forming units (CFU) spread on 20-mm diameter steel carriers and exposed to a broad-spectrum UV-C light source for 10, 20, and 30 minutes at a 1.5 m (5 feet) distance. Post-UV survivors on the coupons were subsequently plated. Colony counts and log reductions were recorded, calculated, and compared to untreated control carriers. Identification of all isolates were confirmed by MALDI-TOF and morphology was visualized by microscopy.

Results:

We observed an increased susceptibility of C. auris to UV-C in 8 isolates belonging to clades I, II and IV with increasing UV exposure time. The range of log kill (0.8–1.19) was highest for these isolates at 30 minutes. But relatively no change in log kill (0.04–0.35) with increasing time in isolates belonging to clade III were noted. Interestingly, C. auris isolates susceptible to UV-C were mostly nonaggregating, but the isolates that were more resistant to UV exposure formed aggregates.

Conclusions:

Our study suggests variability in susceptibility to UV-C of C. auris isolates belonging to different clades. More studies are needed to assess whether a cumulative impact of prolonged UV-C exposure provides additional benefit.

Candida auris: what have we learned so far?

PURPOSE OF REVIEW

The increasing prevalence of fungal infections due to Candida species has been well described in critically ill patient populations, but in recent years a new species, Candida auris has received attention from the medical community worldwide. We aim to summarize the current knowledge related to C. auris, as new identification techniques, novel antifungal agents and more experience with outbreak management have been published in the past few years.

RECENT FINDINGS

C. auris has been described in several countries, arising independently in separate clades. Its resistance to multiple antifungals and persistent colonization of patients and medical surfaces have become a therapeutic and infection control challenge. Recent elucidation of some of the molecular mechanisms related to pathogenicity and studies of in-vitro efficacy of novel antifungal agents can better guide therapy.

SUMMARY

As C. auris continues to cause outbreaks worldwide, newer, and more efficient identification techniques, novel antifungals, and more knowledge in effective infection control techniques will allow better clinical outcomes in the management and control of invasive fungal disease.

Human Infections Caused by Clonally Related African Clade (Clade III) Strains of Candida auris in the Greater Houston Region

Candida auris is a pathogen of considerable public health importance. It was first reported in 2009. Five clades, determined by genomic analysis and named by the distinct regions where they were initially identified, have been defined. We previously completed a draft genome sequence of an African clade (clade III) strain cultured from the urine of a patient hospitalized in the greater Houston metropolitan region (strain LOM). Although initially uncommon, reports of the African clade in the United States have grown to include a recent cluster in California. Here, we describe a second human C. auris infection in the Houston area. Whole-genome sequence analysis demonstrated the Houston patient isolates to be clonally related to one another but distantly related to other African clade organisms recovered in the United States or elsewhere. Infections in these patients were present on admission to the hospital and occurred several months apart. Taken together, the data demonstrate the emergence and persistence of a clonal C. auris population and highlights the importance of routine high-resolution genomic surveillance of emerging human pathogens in the clinical laboratory.

Inactivation of the multi-drug resistant pathogen Candida auris using ultraviolet germicidal irradiation (UVGI)

BACKGROUND

Candida auris, often a multi-drug resistant fungal pathogen, has become an emerging threat in healthcare settings around the world. Reliable disinfection protocols specifically designed to inactivate C. auris are essential, as many chemical disinfectants commonly used in healthcare settings have been shown to have variable efficacy at inactivating C. auris.

AIM

Ultraviolet germicidal irradiation (UVGI) was investigated as a method to inactivate clinically relevant strains of C. auris.

METHODS

Ten C. auris and two C. albicans isolates were exposed to ultraviolet (UV) energy to determine the UV dose required to inactivate each isolate. Using a UV reactor, each isolate (106 cells/mL) was exposed to 11 UV doses ranging from 10-150 mJ/cm2 and then cultured to assess cell viability.

FINDINGS

An exponential decay model was applied to each dose-response curve to determine inactivation rate constants for each isolate, which ranged from 0.108-0.176 cm2/mJ for C. auris and 0.239-0.292 cm2/mJ for C. albicans. As the model of exponential decay did not accurately estimate the dose beyond 99.9% inactivation, a logistic regression model was applied to better estimate the doses required for 99.999% inactivation. Using this model, significantly greater UV energy was required to inactivate C. auris (103 to 192 mJ/cm2) when compared to C. albicans (78 to 80 mJ/cm2).

CONCLUSION

This study demonstrated UVGI as a feasible approach for inactivating C. auris, although variable susceptibility among isolates must be taken into account. This dose-response data is critical for recommending UVGI dosing strategies to be tested in healthcare settings.

Different efficacies of common disinfection methods against candida auris and other candida species

BACKGROUND

Candida auris can form long-lasting colonies in the hospital environment and on human skin. There is limited evidence regarding the efficacy of different methods and products for disinfecting hospitals and colonized patients to prevent the spread of C. auris.

METHODS

The minimum inhibitory concentration of three disinfectant products ("84" disinfectant, IodineTincture disinfectant, and quaternary ammonium) and 75% ethanol against C. auris and other Candida species were measured. A pig skin model was used to evaluate the efficacy of three hand hygiene products in killing pathogens. The killing effect of ultraviolet-C (253.7 nm) and the LK/CXD bed unit ozone disinfection machine on C. auris was also evaluated.

RESULTS

Thirty seconds of pig skin washing with bacteriostatic hand sanitizer followed by drying and 15 s of ethanol-based gel can completely eradicate the colonization of C. auris (3.00 log₁₀ CFU). The antifungal activity of ultraviolet-C to C. auris inoculated on bed sheets was significantly reduced (P < 0.01) at a distance of 1 m. Candida glabrata and C. auris showed greater resistance to ozone than other Candida species. The ozone could completely eradicate C. auris (3.60 log₁₀ CFU) on bed sheets at dosage of 300 mg/m³ for 40 min of exposure.

CONCLUSIONS

We recommend extending the disinfection times of ultraviolet-C and ozone and emphasizing the effectiveness of washing skin with soap, drying skin, and then applying an ethanol-based gel to remove C. auris from skin.

Review on Antifungal Resistance Mechanisms in the Emerging Pathogen Candida auris

Candida auris is an emerging multi-drug resistant yeast, that causes major issues regarding patient treatment and surface disinfection in hospitals. Indeed, an important proportion of C. auris strains isolated worldwide present a decreased sensitivity to multiple and sometimes even all available antifungals. Based on recent tentative breakpoints by the CDC, it appears that in the USA about 90, 30, and < 5% of isolates have been resistant to fluconazole, amphotericin B, and echinocandins, respectively. To date, this has lead to a low therapeutic success. Furthermore, C. auris is prone to cause outbreaks, especially since it can persist for weeks in a nosocomial environment and survive high-end disinfection procedures. In this review, we describe the molecular resistance mechanisms to antifungal drugs identified so far in C. auris and compare them to those previously discovered in other Candida species. Additionally, we examine the role that biofilm formation plays in the reduced antifungal sensitivity of this organism. Finally, we summarize the few insights on how this yeast survives on hospital surfaces and discuss the challenge it presents regarding nosocomial environment disinfection.

Candida auris in various hospitals across Kuwait and their susceptibility and molecular basis of resistance to antifungal drugs

BACKGROUND

Candida auris, a multidrug-resistant species, has the propensity of nosocomial transmission despite normal decontamination procedures. Here, we describe the isolation of C auris from patients in various hospitals in Kuwait during 2014-2018. Susceptibility to antifungal drugs and molecular basis of resistance to fluconazole, voriconazole and micafungin were also studied.

METHODS

Candida auris (n = 314) obtained from 126 patients in eight hospitals were studied. All isolates were identified by PCR amplification and/or PCR-sequencing of ribosomal DNA (rDNA). Antifungal susceptibility was determined by Etest. Molecular basis of resistance to fluconazole and micafungin was studied by PCR-sequencing of ERG11 and FKS1 genes, respectively.

FINDINGS

Bloodstream (n = 58), urine (n = 124), respiratory (n = 98) and other (n = 34) specimens yielded 314 C auris isolates. The proportion of bloodstream C auris among all yeast isolates was higher (42 of 307, 13.7%) in 2018 as compared to 2014-2017 (16 of 964, 1.7%) (P = .001). More bloodstream isolates (42 of 139) were cultured in 2018 than during 2014-2017 (16 of 175) (P = .001). Resistance to amphotericin B, fluconazole, voriconazole and micafungin was detected in 27.1%, 100%, 41.1% and 1.7% isolates, respectively. Fluconazole-resistant isolates contained either Y132F or K143R mutation in ERG11. Isolates with K143R mutation were additionally resistant to voriconazole. Micafungin-resistant isolates contained S639F mutation in hot spot 1 of FKS1.

CONCLUSIONS

Our study highlights spreading of C auris in major hospitals across Kuwait and its increasing role as a bloodstream pathogen in 2018. Cross-resistance to voriconazole was also seen in isolates with K143R mutation in ERG11, while micafungin-resistant isolates harboured S639F mutation in hot spot 1 of FKS1.

Ongoing Challenges with Healthcare-Associated Candida auris Outbreaks in Oman

Candida auris has emerged in the past decade as a multi-drug resistant public health threat causing health care outbreaks. Here we report epidemiological, clinical, and microbiological investigations of a C. auris outbreak in a regional Omani hospital between April 2018 and April 2019. The outbreak started in the intensive care areas (intensive care unit (ICU), coronary care unit (CCU), and high dependency unit) but cases were subsequently diagnosed in other medical and surgical units. In addition to the patients' clinical and screening samples, environmental swabs from high touch areas and from the hands of 35 staff were collected. All the positive samples from patients and environmental screening were confirmed using MALDI-TOF, and additional ITS-rDNA sequencing was done for ten clinical and two environmental isolates. There were 32 patients positive for C. auris of which 14 (43.8%) had urinary tract infection, 11 (34.4%) had candidemia, and 7 (21.8%) had asymptomatic skin colonization. The median age was 64 years (14-88) with 17 (53.1%) male and 15 (46.9%) female patients. Prior to diagnosis, 21 (65.6%) had been admitted to the intensive care unit, and 11 (34.4%) had been nursed in medical or surgical wards. The crude mortality rate in our patient's cohort was 53.1. Two swabs collected from a ventilator in two different beds in the ICU were positive for C. auris. None of the health care worker samples were positive. Molecular typing showed that clinical and environmental isolates were genetically similar and all belonged to the South Asian C. auris clade I. Most isolates had non-susceptible fluconazole (100%) and amphotericin B (33%) minimal inhibitory concentrations (MICs), but had low echinocandin and voriconazole MICs. Despite multimodal infection prevention and control measures, new cases continued to appear, challenging all the containment efforts.

Control of Candida auris in healthcare institutions: Outcome of an International Society for Antimicrobial Chemotherapy expert meeting

Candida auris (C. auris) is an emerging fungal pathogen causing invasive infections and outbreaks that have been difficult to control in healthcare facilities worldwide. There is a lack of current evidence for pragmatic infection prevention and control recommendations. The aim of this paper was to review the epidemiology of C. auris and identify best practices with a panel of experts, in order to provide guidance and recommendations for infection prevention and control measures based on available scientific evidence, existing guidelines and expert opinion. The Infection Prevention and Control working group of the International Society of Antimicrobial Chemotherapy organised an expert meeting with infection prevention and mycology experts to review recommendations for healthcare workers on infection prevention and control measures for C. auris at inpatient healthcare facilities. The most common interventions included: screening, standard precautions, cleaning and disinfection, inpatient transfer, outbreak management, decolonisation, and treatment.

The Epidemiology and Prevention of Candida auris

PURPOSE OF REVIEW

Candida auris has recently emerged as a pathogen with the potential for nosocomial transmission and outbreaks. The aim of this review is to summarize the global dissemination of this pathogen, characterize patient and facility characteristics associated with infection and outbreaks, and outline evidence to support interventions to prevent of transmission in the healthcare setting.

RECENT FINDINGS

C. auris has emerged separately in four clades, with international spread within a decade of its first identification and report. Acquisition and infection have predominantly been identified as healthcare-associated events. The presence of invasive devices, intensive care, and broad-spectrum antibiotic and antifungal use may be important risk factors for the development of infection due to C. auris. Nosocomial transmission is likely associated with colonization density and suboptimal infection prevention practices. The optimal strategy for reducing transmission from the environment requires further study. Candida auris is a recently emerging fungal pathogen that may cause nosocomial infections and outbreaks. Based on observed transmission patterns and interventions, key prevention measures outlined in the review include case finding and surveillance, hand hygiene, and environmental disinfection.

Killing of Candida auris by UV-C: Importance of exposure time and distance

Background

Candida auris is a globally emerging yeast, causing severe infections in patients with underlying diseases. This yeast is responsible for several outbreaks within healthcare facilities, where it can be found on hospital surfaces and patient care devices. Spread from these fomites may be prevented by improving the decontamination of hospital surfaces. UV‐C decontamination may constitute an effective adjunct to routine room cleaning.

Objectives

Our aim was to investigate the effect of different UV‐C exposure times and distance in killing C auris, using strains from different countries.

Methods

Candida auris was seeded on glass slides and exposed to UV‐C for 5, 10, 20 and 30 minutes at 2 and 4 m.

Results

A maximal effect of C auris killing was found after 30 minutes of UV‐C exposure at 2 m. With half the time or twice the distance, the efficacy strongly diminished to ~10 and ~50 fold, respectively. At suboptimal exposure times and distances, the C auris strains from Japan/Korea were more sensitive to UV‐C killing than C auris strains originating from Venezuela, Spain and India.

Conclusions

Altogether, UV‐C exposure times and distance are the most critical parameters to kill C auris, while strain variations of C auris also determine UV‐C efficacy. Future studies should aim to determine the effect and place of UV‐C on surface decontamination in hospital setting.