So Many Diagnostic Tests, So Little Time: Review and Preview of Candida auris Testing in Clinical and Public Health Laboratories

Enhancing Candida auris diagnosis: a comprehensive evaluation of VIASURE Candida auris real-time PCR detection kit for rapid diagnostic responses

Candida auris, a yeast that is highly resistant to antifungal treatments, represents a significant healthcare concern due to its rapid spread through surface contamination and patient colonization. A recent outbreak at the Miguel Servet University Hospital in Zaragoza, Spain, highlighted the urgent need for rapid diagnostic responses. The current 4-day duration for microbiological culture results hinders timely patient isolation and transmission prevention. This study aims to evaluate the VIASURE Candida auris Real-Time PCR Detection Kit (Certest Biotec) for diagnostic performance and analytical specificity compared to the standard methodology based on culture and MALDI-TOF MS characterization. From August 2023 to December 2023, the Microbiology Service of the Miguel Servet University Hospital processed 816 diagnostic samples. Accuracy testing resulted in adequate clinical validation values, as presented here: sensitivity, 0.98 (95% confidence interval [CI], 0.90 to 1); specificity, 1 (95% CI, 0.99 to 1); positive predictive value, 0.98 (95% CI, 0.90 to 1); and negative predictive value, 1 (95% CI, 0.99 to 1). The implementation of this molecular biology test in the laboratory promises to improve diagnostic efficiency by allowing rapid patient isolation, initiation of appropriate treatment, and effective isolation measures.

IMPORTANCE

Candida auris, a resilient and antifungal-resistant yeast, poses a significant healthcare threat due to its rapid spread. A recent outbreak at a hospital in Zaragoza, Spain, emphasized the urgent need for faster diagnostics. The current four-day wait for culture results hampers timely patient isolation. This retrospective and comparative study demonstrates the favorable clinical parameters of a commercially available molecular diagnostic kit. The kit allows enhanced diagnostic efficiency, swifter patient isolation, and more effective control measures in the laboratory. In conclusion, the kit addresses the pressing challenges presented by C. auris in healthcare.

Diagnostic Challenges in Fungal Coinfections Associated With Global COVID-19

The early diagnosis of opportunistic infections is a critical concern for patient care worldwide, particularly in the context of the COVID-19 pandemic. This review examines the challenges and advancements in the management and early diagnosis of opportunistic fungal infections, which have become increasingly prominent during the pandemic. Using multiple sources, including curated databases such as PubMed and Scopus, as well as Google Scholar for broader literature searches, we systematically reviewed studies on COVID-19-associated fungal infections, with a focus on candidiasis, mucormycosis, and aspergillosis. The inclusion criteria encompassed peer-reviewed articles, clinical case reports, and cohort studies that discussed diagnostic methods, clinical outcomes, and treatment responses. Data were systematically extracted and analyzed to identify key trends and gaps in current diagnostic practices. Given the significance of opportunistic fungal infections-particularly the selected species-this review provides a comprehensive analysis of diagnostic challenges and advancements in the context of COVID-19 and beyond. Currently, there is no definitive strategy for effectively addressing these opportunistic pathogens, highlighting the need for continued research and innovation. Despite advancements in medical technology, opportunistic fungal infections continue to pose significant challenges to early and accurate diagnosis. The COVID-19 pandemic has exacerbated these challenges, with secondary fungal infections contributing to increased morbidity and mortality rates. This review highlights the complexities of diagnosing fungal coinfections and emphasizes the urgent need for improved diagnostic strategies. Enhancing the early and accurate detection of these infections is critical for effective patient management, particularly during viral pandemics. Addressing the challenges outlined in this review requires innovative diagnostic approaches to improve patient outcomes and reduce the burden of opportunistic infections on global healthcare systems.

Keep the Hospital Clean: Diagnostic Performance of Ten Different Molecular and Culture-Based Methods to Detect Candidozyma (Candida) auris

RATIONALE

Candidozyma auris (formerly Candida auris) is a globally emerging potentially multi-drug resistant human pathogenic yeast. To detect C. auris we aimed to compare different culture-, and molecular-based methods.

METHODS

Rectal swabs routinely collected in clinical care were spiked with different concentrations of C. auris. Co-infection/colonization was mimicked by spiking part of these samples with other pathogenic Candida species. Spiked materials were cultured at 37 or 42 °C using CHROMagar Candida and CHROMagar Candida Plus plates. In parallel, samples were incubated in a dulcitol salt enrichment broth. Additionally, we compared seven in-house and commercial molecular tests on the direct material and from the broth one day after inoculation.

RESULTS

Culture-based methods showed sensitivities up to 100% within 48 h of incubation, although sensitivity decreased as low as 44% at lower concentrations (≤ 50 CFU per inoculum), in the presence of an abundance of other species and at higher temperature (42 °C). Incubation at 42 °C made visual identification possible since other species with similar colony morphologies did not grow at this temperature. No added value of using the dulcitol salt enrichment broth was found. qPCR on direct materials was highly sensitive and specific (both up to 100%) but major differences between various molecular tests were observed.

CONCLUSION

We showed that both culture-based and molecular methods are sensitive for diagnosing C. auris. The clinical setting (routine screening versus an outbreak), local prevalence and the load in those that carry or are infected by C. auris are important factors to consider when determining which diagnostic tests should be employed.

Impact of Candida auris on Critically Ill Patients: A Three-Year Observational Study in a Greek Intensive Care Unit

Candida auris has emerged as a multidrug-resistant yeast implicated in healthcare-associated invasive infections and hospital outbreaks. The aim of the current 38-month period observational study in a multidisciplinary Intensive Care Unit (ICU) was to analyze the epidemiology, potential risk factors, management strategies, and patient outcomes of patients with C. auris. During the study period, 32 patients were identified with C. auris infection (6 patients) or colonization (26 patients) and their clinical characteristics and treatment-related factors were compared. Identification of C. auris isolates was confirmed by MALDI-TOF spectrometry. According to our results, regarding patient-related factors, no significant differences were identified. Regarding treatment-related factors, the proportion of patients already receiving corticosteroids (34.6% vs. 83.3%, p = 0.064) or being on renal replacement treatment (7.7% vs. 33.3%) was higher in infected patients. Median time elapsed from ICU admission to first positive culture was 7 (1-21) days and half of cases were ICU-imported. All strains were resistant to fluconazole and susceptible to echinocandines and amphotericin B. Crude mortality of the study population was 43.75%, similar to other previously reported candidemias. Rapid identification of C. auris, continued surveillance, and infection control practices are important elements for controlling successfully its spread in the hospital setting and for establishing promptly its transition from commensalism to infection.

Candida auris: A Continuing Threat

Candida auris is a World Health Organization critical-priority fungal pathogen that has variable resistance to antifungal treatments. Multiple clades have been identified through genomic analysis and have appeared in different geographic locations simultaneously. Due to a combination of factors including antifungal resistance, ability to colonize and persist in the environment, and thermotolerance, it can thrive. Infected patients are associated with a high mortality rate, especially those with multiple health risk factors like those associated with other Candida species. This review highlights the current situation of this pathogen to help provide guidance for future work.

Candida auris Diagnostics: Identification and Screening

Candida auris is an emerging yeast species classified as an urgent threat by the Centers for Disease Control and Prevention due to its ability to colonize numerous surfaces, its ability to spread through health care systems, its elevated antifungal resistance, and its high mortality rate. Accurate detection of C auris from patient specimens is crucial for containing, preventing the spread of, and managing patients with C auris. Here, we review currently available diagnostics, current screening guidance, and identify areas where diagnostics could improve.

Simulating a travel-related origin of Candida auris in New York-New Jersey

Candida auris first appeared in the United States in 2013 in New York-New Jersey (NY-NJ) and led to an unprecedented outbreak since 2016. We hypothesized C. auris' introduction to NY-NJ was not a random event but related to travel patterns between South Asia and NY-NJ. New York City is a US hub for international passengers, including those from South Asia. We tested the hypothesis by simulating introductions to NY-NJ with a Monte Carlo simulation based on travel from South Asia, proportion of US population in NY-NJ, proportion of hospitals in NY-NJ, and finally, proportion of all travelers entering the United States through NY-NJ. The C. auris outbreak occurred during increasing travel and trade, and South Asia travel routes predict the distribution of early C. auris cases in NY-NJ. The local mobility network within hospitals and extended stay healthcare facilities were also relevant in the spread of C. auris. Our observations and simulations link travel patterns to C. auris origin and spread and warrant further investigations for understanding the continued spread of the pathogen.

IMPORTANCE

Candida auris is an emerging fungal pathogen, with resistance to several antifungal drugs. Serious C. auris infections affect hospitalized patients and residents of long-term care facilities, although the pathogen can also be present on a healthy individual's skin. Many studies have shown international introductions of C. auris to the United States. Here, we present a simulation that supports the hypothesis that the earlier introductions of C. auris in the New York-New Jersey area are not random but related to travel networks.

Evaluation of usage of readily accessible Enterobacteriaceae differential and selective media for identifying Candida auris

BACKGROUND

Candida auris is a drug-resistant fungal pathogen. Diagnosing it is challenging due to the need for modern techniques. This study aims to evaluate the usefulness of Enterobacteriaceae culture media in screening and identifying Candida auris, as those media are accessible in resource-limited laboratories.

METHOD

The study used various yeast strains, including Candida auris, to challenge bacteriologic media and evaluated the effectiveness of different Enterobacteriaceae differential and selective media in identifying and differentiating Candida auris from other yeasts.

RESULTS

All yeasts can grow on all Enterobacteriaceae differential and selective media during various incubation times, resulting in variable colony sizes. Simon's Citrate Agar medium can differentiate Candida auris and other members of C. haemulonii complex from other yeasts.

CONCLUSION

Although definitive identification of Candida auris is challenging and requires specific methods, Citrate Agar could be a preliminary screening method in source-limited regions.

Assessment of LAMPAuris for Rapid Detection of Candida auris in Clinical Specimens

Candida auris is a pathogenic yeast frequently exhibiting multidrug resistance and thus warrants special attention. The prompt detection and proper identification of this organism are needed to prevent its spread in healthcare facilities. The authors of this paper had previously developed LAMPAuris, a loop-mediated isothermal amplification assay, for the specific detection of C. auris. LAMPAuris is evaluated in this report for its ability to identify C. auris from five clades and to detect it from clinical specimens. A total of 103 skin swab samples were tested in comparison with a culture-based method and C. auris-specific SYBR green qPCR. The results show that the LAMPAuris assay had specificities ranging from 97 to 100% and sensitivities ranging from 66 to 86%. The lower sensitivity could be attributed to DNA degradation caused by the prolonged storage of the samples. In conclusion, LAMPAuris proved to be a rapid and reliable method for identifying C. auris and for detecting it in clinical specimens. Fresh specimens should ensure better yield and higher sensitivities.

First imported case of Candida auris infection in Milan, Italy: genomic characterisation

PURPOSE

Candida auris, an emerging multidrug-resistant yeast, has been reported worldwide. In Italy, the first case was reported in 2019. We describe the first case of C. auris, imported from Greece, in Milan, using whole genome sequencing to characterise mutations associated with antifungal resistance.

CASE PRESENTATION

On October 2022 an 80-year-old Italian man was hospitalised in Greece. In the absence of clinical improvement, the patient was transferred to our hospital, in Italy, where blood culture resulted positive for C. auris. Despite therapy, the patient died of septic shock. In a phylogenetic analysis the genome was assigned to Clade I with strains from Kenya, United Arab Emirates and India. D1/D2 region resulted identical to a Greek strain, as for many other strains from different World regions, highlighting the diffusion of this strain.

CONCLUSION

Importation of C. auris from abroad has been previously described. We report the first case of C. auris imported into Italy from Greece, according to phylogenetic analysis. This case reinforces the need for monitoring critically ill hospitalised patients also for fungi and addresses the need for the standardisation of susceptibility testing and strategies for diagnosis and therapy.

A simple and sensitive test for Candida auris colonization, surveillance, and infection control suitable for near patient use

Candida auris is a multidrug-resistant fungal pathogen with a propensity to colonize humans and persist on environmental surfaces. C. auris invasive fungal disease is being increasingly identified in acute and long-term care settings. We have developed a prototype cartridge-based C. auris surveillance assay (CaurisSurV cartridge; "research use only") that includes integrated sample processing and nucleic acid amplification to detect C. auris from surveillance skin swabs in the GeneXpert instrument and is designed for point-of-care use. The assay limit of detection (LoD) in the skin swab matrix was 10.5 and 14.8 CFU/mL for non-aggregative (AR0388) and aggregative (AR0382) strains of C. auris, respectively. All five known clades of C. auris were detected at 2-3-5× (31.5-52.5 CFU/mL) the LoD. The assay was validated using a total of 85 clinical swab samples banked at two different institutions (University of California Los Angeles, CA and Wadsworth Center, NY). Compared to culture, sensitivity was 96.8% (30/31) and 100% (10/10) in the UCLA and Wadsworth cohorts, respectively, providing a combined sensitivity of 97.5% (40/41), and compared to PCR, the combined sensitivity was 92% (46/50). Specificity was 100% with both clinical (C. auris negative matrix, N = 31) and analytical (non-C. auris strains, N = 32) samples. An additional blinded study with N = 60 samples from Wadsworth Center, NY yielded 97% (29/30) sensitivity and 100% (28/28) specificity. We have developed a completely integrated, sensitive, specific, and 58-min prototype test, which can be used for routine surveillance of C. auris and might help prevent colonization and outbreaks in acute and chronic healthcare settings.

IMPORTANCE

This study has the potential to offer a better solution to healthcare providers at hospitals and long-term care facilities in their ongoing efforts for effective and timely control of Candida auris infection and hence quicker response for any potential future outbreaks.

A lateral flow immunoassay for the rapid identification of Candida auris from isolates or directly from surveillance enrichment broths

Introduction

Candida auris is a recently discovered yeast with a multi-drug resistant profile associated with high mortality rates. The rapid identification of Candida auris in hospital settings is crucial to allow appropriate therapeutic and rapid implementation of infection management measures. The aim of this study was to develop a lateral flow immunoassay (LFIA) for the rapid identification of Candida auris.

Methods

Highly specific monoclonal antibodies were obtained by immunizing mice with membrane proteins from Candida auris which were then used to develop a LFIA whose performance was assessed by testing 12 strains of Candida auris and 37 strains of other Candida species. Isolates were grown on either Sabouraud dextrose, CHROMagarTM Candida Plus or HardyCHROMTM Candida + auris agar plates. The strains were also cultured on salt sabouraud-dextrose with chloramphenicol or a commercially available Salt-Sabouraud Dulcitol Broth with chloramphenicol and gentamicin, and processed using a simple centrifugation protocol to recover a pellet. Finally, the colonies or yeast extract were transferred to the LFIA to determine the specificity and sensitivity of the assay.

Results

The LFIA reached 100% specificity and sensitivity from solid agar plates. For both enrichment broths, some Candida non-auris species were able to grow, but the LFIA remained 100% specific. The use of a dextrose-based sabouraud broth resulted in earlier identification with the LFIA, with most of the Candida auris strains detected at 24 h.

Conclusion

The developed LFIA prototype represents a powerful tool to fight the emerging threat of Candida auris. Clinical validation represents the next step.

Development of a Recombinase-Aided Amplification Assay for the Rapid Detection of Candida auris

Candida auris (C. auris) was first discovered in Japan in 2009 and has since spread worldwide. It exhibits strong transmission ability, high multidrug resistance, blood infectivity, and mortality rates. Traditional diagnostic techniques for C. auris have shortcomings, leading to difficulty in its timely diagnosis and identification. Therefore, timely and accurate diagnostic assays for clinical samples are crucial. We developed a novel, rapid recombinase-aided amplification (RAA) assay targeting the 18S rRNA, ITS1, 5.8S rRNA, ITS2, and 28S rRNA genes for C. auris identification. This assay can rapidly amplify DNA at 39 °C in 20 min. The analytical sensitivity and specificity were evaluated. From 241 clinical samples collected from pediatric inpatients, none were detected as C. auris-positive. We then prepared simulated clinical samples by adding 10-fold serial dilutions of C. auris into the samples to test the RAA assay's efficacy and compared it with that of real-time PCR. The assay demonstrated an analytical sensitivity of 10 copies/μL and an analytical specificity of 100%. The lower detection limit of the RAA assay for simulated clinical samples was 101 CFU/mL, which was better than that of real-time PCR (102-103 CFU/mL), demonstrating that the RAA assay may have a better detection efficacy for clinical samples. In summary, the RAA assay has high sensitivity, specificity, and detection efficacy. This assay is a potential new method for detecting C. auris, with simple reaction condition requirements, thus helping to manage C. auris epidemics.

Candida auris screening practices at healthcare facilities in the United States: An Emerging Infections Network survey

We surveyed members of the Emerging Infections Network about Candida auris screening practices at US healthcare facilities. Only 37% of respondents reported conducting screening; among these, 75% reported detection of at least 1 C. auris case in the last year. Increased screening could improve C. auris detection and prevent spread.

Navigating the Challenges of Candida auris Colonization in Rehabilitation Settings

ABSTRACT

Candida auris is a highly transmissible yeast that is capable of causing invasive and fatal infections, particularly among persons with underlying medical conditions. Its incidence is rising, especially among patients cared for in post-acute care facilities. Individuals colonized with the yeast may be cared for in inpatient rehabilitation settings, without heightened risk for invasive infection and/or transmission to others, as long as appropriate infection control measures are followed. This article reviews key information for rehabilitation nurses caring for persons with C. auris , including risk factors for infection, the need for contact precautions, appropriate disinfection practices for therapy and diagnostic equipment, and critical components of safe transitions in the care of these patients.

Evaluation of the Vitek 2 system for antifungal susceptibility testing of Candida auris using a representative international panel of clinical isolates: overestimation of amphotericin B resistance and underestimation of fluconazole resistance

Although the Vitek 2 system is broadly used for antifungal susceptibility testing of Candida spp., its performance against Candida auris has been assessed using limited number of isolates recovered from restricted geographic areas. We therefore compared Vitek 2 system with the reference Clinical and Laboratory Standards Institute (CLSI) broth microdilution method using an international collection of 100 C. auris isolates belonging to different clades. The agreement ±1 twofold dilution between the two methods and the categorical agreement (CA) based on the Centers for Disease Control and Prevention's (CDC's) tentative resistance breakpoints and Vitek 2-specific wild-type upper limit values (WT-ULVs) were determined. The CLSI-Vitek 2 agreement was poor for 5-flucytosine (0%), fluconazole (16%), and amphotericin B (29%), and moderate for voriconazole (61%), micafungin (67%), and caspofungin (81%). Significant interpretation errors were recorded using the CDC breakpoints for amphotericin B (31% CA, 69% major errors; MaEs) and fluconazole (69% CA, 31% very major errors; VmEs), but not for echinocandins (99% CA, 1% MaEs for both micafungin and caspofungin) for which the Vitek 2 allowed correct categorization of echinocandin-resistant FKS1 mutant isolates. Discrepancies were reduced when the Vitek 2 WT-ULV of 16 mg/L for amphotericin B (98% CA, 2% MaEs) and of 4 mg/L for fluconazole (96% CA, 1% MaEs, 3% VmEs) were used. In conclusion, the Vitek 2 system performed well for echinocandin susceptibility testing of C .auris. Resistance to fluconazole was underestimated whereas resistance to amphotericin B was overestimated using the CDC breakpoints of ≥32 and ≥2 mg/L, respectively. Vitek 2 minimun inhibitory concentrations (MICs) >4 mg/L indicated resistance to fluconazole and Vitek 2 MICs ≤16 mg/L indicated non-resistance to amphotericin B.

Frequency of Detection of Candida auris Colonization Outside a Highly Endemic Setting: What Is the Optimal Strategy for Screening of Carriage?

Candida auris outbreaks are increasingly frequent worldwide. In our 1000-bed hospital, an endemic transmission of C. auris was established in two of five intensive care units (ICUs). Aims of our study were to describe the occurrence of new cases of C. auris colonization and infection outside the endemic ICUs, in order to add evidence for future policies on screening in patients discharged as negative from an endemic setting, as well as to propose a new algorithm for screening of such high-risk patients. From 26 March 2021 to 26 January 2023, among 392 patients who were diagnosed as colonized or infected with C. auris in our hospital, 84 (21.4%) received the first diagnosis of colonization or infection outside the endemic ICUs. A total of 68 patients out of 84 (81.0%) had a history of prior admission to the endemic ICUs. All were screened and tested negative during their ICU stay with a median time from last screening to discharge of 3 days. In 57/68 (83.8%) of patients, C. auris was detected through screening performed after ICU discharge, and 90% had C. auris colonization detected within 9 days from ICU discharge. In 13 cases (13/57 screened, 22.8%), the first post-ICU discharge screening was negative. In those not screened, candidemia was the most frequent event of the first C. auris detection (6/11 patients not screened). In settings where the transmission of C. auris is limited to certain wards, we suggest screening both at discharge from the endemic ward(s) even in case of a recent negative result, and at least twice after admission to nonendemic settings.

Operational impact of decreased turnaround times for Candida auris screening tests in a tertiary academic medical center

Objective

Assess turnaround time (TAT) and cost-benefit of on-site C. auris screening and its impact on length of stay (LOS) and costs compared to reference laboratories.

Design

Before-and-after retrospective cohort study.

Setting

Large-tertiary medical center.

Methods

We validated an on-site polymerase chain reaction-based testing platform for C. auris and retrospectively reviewed hospitalized adults who screened negative before and after platform implementation. We constructed multivariable models to assess the association of screening negative with hospital LOS/cost in the pre and postimplementation periods. We adjusted for confounders such as demographics and indwelling device use, and compared TATs for all samples tested.

Results

The sensitivity and specificity of the testing platform were 100% and 98.11%, respectively, compared to send-out testing. The clinical cohort included 287 adults in the pre and 1,266 postimplementation period. The TAT was reduced by more than 2 days (3 (interquartile range (IQR): 2.0, 7.0) vs 0.42 (IQR: 0.24, 0.81), p < 0.001). Median LOS was significantly lower in the postimplementation period; however, this was no longer evident after adjustment. In relation to total cost, the time period had an effect of $6,965 (95% CI: -$481, $14,412); p = 0.067) on reducing the cost. The median adjusted total cost per patient was $7,045 (IQR: $3,805, $13,924) less in the post vs the preimplementation period.

Conclusions

Our assessment did not find a statistically significant change in LOS, nevertheless, on-site testing was not cost-prohibitive for the institution. The value of on-site testing may be supported if an institutional C. auris reduction strategy emphasizes faster TATs.

Molecular Detection of Candida auris Using DiaSorin Molecular Simplexa® Detection Kit: A Diagnostic Performance Evaluation

Candida auris is a globally emerging fungal pathogen that is associated with healthcare-related infections. The accurate and rapid detection of C. auris is crucial for effective infection prevention, control, and patient management. This study aimed to validate the analytical and diagnostic performance of the DiaSorin Molecular C. auris Detection Kit. The analytical specificity, sensitivity, and reproducibility of the assay were evaluated. The limit of detection (LOD) was determined to be 266 CFU/µL using the ZeptoMetrix Candida auris Z485 strain and standard calibration curves. The assay demonstrated high analytical specificity and showed no amplification against a diverse panel of bacteria and fungi. Clinical validation was conducted using deidentified residual axillary/groin surveillance culture specimens from C. auris culture-positive and culture-negative patients. The DiaSorin Molecular Detection Kit exhibited 100% agreement in sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) when compared to cultures coupled with MALDI-TOF identification. Intra- and inter-reproducibility testing demonstrated consistent and reliable diagnostic performance. This validated assay offers rapid and accurate detection of C. auris, facilitating timely implementation of infection control measures and appropriate patient care. The DiaSorin Molecular C. auris Detection Kit has the potential to aid in controlling the outbreaks caused by this emerging fungal pathogen. Providing a reliable diagnostic tool can contribute to the effective management and containment of C. auris infections in healthcare settings and ultimately improve patient outcomes.

Development of a Novel Method for the Clinical Visualization and Rapid Identification of Multidrug-Resistant Candida auris

Outbreaks of multidrug-resistant Candida auris infections, associated with a mortality rate of 30% to 60%, are of serious global concern. Candida auris demonstrates high transmission rates in hospital settings; however, its rapid and accurate identification using currently available clinical identification techniques is challenging. In this study, we developed a rapid and effective method for detecting C. auris based on recombinase-aided amplification combined with lateral flow strips (RAA-LFS). We also screened the appropriate reaction conditions. Furthermore, we investigated the specificity and sensitivity of the detection system and its ability to distinguish other fungal strains. Candida auris was accurately identified and differentiated from related species at 37°C within 15 min. The minimum detection limit was 1 CFU (or 10 fg/reaction) and was not affected by high concentrations of related species or host DNA. The simple and cost-efficient detection method established in this study exhibited high specificity and sensitivity and successfully detected C. auris in simulated clinical samples. Compared with other traditional detection methods, this method greatly reduces the time and cost of testing and is thus suitable for hospitals or clinics in remote underfunded areas for screening C. auris infection and colonization. IMPORTANCE Candida auris is a highly lethal, multidrug-resistant, invasive fungus. However, conventional methods of C. auris identification are time-consuming and laborious and have low sensitivity and high error rates. In this study, a new molecular diagnostic method based on recombinase-aided amplification combined with lateral flow strips (RAA-LFS) was developed, and accurate results could be obtained by catalyzing the reaction at body temperature for 15 min. This method can be used for rapid clinical detection of C. auris, consequently saving valuable treatment time for patients.

Overestimation of Amphotericin B Resistance in Candida auris with Sensititre YeastOne Antifungal Susceptibility Testing: a Need for Adjustment for Correct Interpretation

Significant variation in minimal inhibitory concentrations (MIC) has been reported for amphotericin B (AMB) and C. auris, depending on the antifungal susceptibility testing (AFST) method. Although the Sensititre YeastOne (SYO) is widely used in routine laboratory testing, data regarding its performance for the AFST of C. auris are scarce. We tested AMB against 65 C. auris clinical isolates with the SYO and the reference methodology by the Clinical and Laboratory Standards Institute (CLSI). The essential agreement (EA, ±1 dilution) between the two methods and the categorical agreement (CA) based on the Centers for Disease Control and Prevention (CDC)'s tentative breakpoint of MIC ≥ 2 mg/L were determined. The SYO wild type upper limit value (WT-UL) was determined using the ECOFFinder. The modal (range) CLSI growth inhibitory MIC was lower than the SYO colorimetric MIC [1(0.25-1) versus 2(1-8) mg/L, respectively]). The CLSI-colorimetric SYO EA was 29% and the CA was 11% (89% major errors; MaE). MaE were reduced when the SYO WT-UL of 8 mg/L was used (0% MaE). Alternatively, the use of SYO growth inhibition endpoints of MIC-1 (75% growth inhibition) or MIC-2 (50% growth inhibition) resulted in 88% CA with 12% MaE and 97% CA with 3% MaE, respectively. In conclusion, SYO overestimated AMB resistance in C. auris isolates when colorimetric MICs, as per SYO instructions and the CDC breakpoint of 2 mg/L, were used. This can be improved either by using the method-specific WT-UL MIC of 8 mg/L for colorimetric MICs or by determining growth inhibition MIC endpoints, regardless of the color. IMPORTANCE Candida auris is an emerging and frequently multidrug-resistant fungal pathogen that accounts for life-threatening invasive infections and nosocomial outbreaks worldwide. Reliable AF is important for the choice of the optimal treatment. Commercial methods are frequently used without prior vigorous assessment. Resistance to AMB was over-reported with the commercial colorimetric method Sensititre YeastOne (SYO). SYO produced MICs that were 1 to 2 twofold dilutions higher than those of the reference CLSI method, resulting in 89% MaE. MaE were reduced using a SYO-specific colorimetric wild type upper limit MIC value of 8 mg/L (0%) or a 50% growth inhibition endpoint (3%).

Increasing Number of Cases Due to Candida auris in North Italy, July 2019-December 2022

Candida auris is an emerging fungus that represents a serious health threat globally. In Italy, the first case was detected in July 2019. Then, one case was reported to the Ministry of Health (MoH) on January 2020. Nine months later, a huge number of cases were reported in northern Italy. Overall, 361 cases were detected in 17 healthcare facilities between July 2019 and December 2022 in the Liguria, Piedmont, Emilia-Romagna, and Veneto regions, including 146 (40.4%) deaths. The majority of cases (91.8%) were considered as colonised. Only one had a history of travel abroad. Microbiological data on seven isolates showed that all but one strain (85.7%) were resistant to fluconazole. All the environmental samples tested negative. Weekly screening of contacts was performed by the healthcare facilities. Infection prevention and control (IPC) measures were applied locally. The MoH nominated a National Reference Laboratory to characterise C. auris isolates and store the strains. In 2021, Italy posted two messages through the Epidemic Intelligence Information System (EPIS) to inform on the cases. On February 2022, a rapid risk assessment indicated a high risk for further spread within Italy, but a low risk of spread to other countries.

Candida auris in skilled nursing facilities

Candida auris is a fungal organism resistant to several classes of antifungals. Since its identification in 2009, it has gained worldwide attention in healthcare for its virulence and resistance to commonly used antifungal therapeutics. Although its origin and mechanisms of transmission are not fully elucidated, it is widely recognized as a high priority healthcare-associated pathogen. Infection control efforts in skilled nursing facilities have been very challenging due to the tendency of C. auris to persist in the environment and colonize residents. In this narrative review, we discuss the epidemiology and infection prevention of C. auris in skilled nursing facilities. We also identify challenges in the diagnosis and management of both symptomatic infections and asymptomatic colonization.

Candida auris Pan-Drug-Resistant to Four Classes of Antifungal Agents

Candida auris is an urgent antimicrobial resistance threat due to its global emergence, high mortality, and persistent transmissions. Nearly half of C. auris clinical and surveillance cases in the United States are from the New York and New Jersey Metropolitan area. We performed genome, and drug-resistance analysis of C. auris isolates from a patient who underwent multi-visceral transplantation. Whole-genome comparisons of 19 isolates, collected over 72 days, revealed closed similarity (Average Nucleotide Identity > 0.9996; Aligned Percentage > 0.9764) and a distinct subcluster of NY C. auris South Asia Clade I. All isolates had azole-linked resistance in ERG11(K143R) and CDR1(V704L). Echinocandin resistance first appeared with FKS1(S639Y) mutation and then a unique FKS1(F635C) mutation. Flucytosine-resistant isolates had mutations in FCY1, FUR1, and ADE17. Two pan-drug-resistant C. auris isolates had uracil phosphoribosyltransferase deletion (FUR1[1Δ33]) and the elimination of FUR1 expression, confirmed by a qPCR test developed in this study. Besides ERG11 mutations, four amphotericin B-resistant isolates showed no distinct nonsynonymous variants suggesting unknown genetic elements driving the resistance. Pan-drug-resistant C. auris isolates were not susceptible to two-drug antifungal combinations tested by checkerboard, Etest, and time-kill methods. The fungal population pattern, discerned from SNP phylogenetic analysis, was consistent with in-hospital or inpatient evolution of C. auris isolates circulating locally and not indicative of a recent introduction from elsewhere. The emergence of pan-drug-resistance to four major classes of antifungals in C. auris is alarming. Patients at high risk for drug-resistant C. auris might require novel therapeutic strategies and targeted pre-and/or posttransplant surveillance.

Global Prevalence and Subgroup Analyses of Coronavirus Disease (COVID-19) Associated Candida auris infections (CACa): A Systematic Review and Meta-Analysis

Background

Increased hospitalisation rates in the Coronavirus disease 19 (COVID‐19) era lead to a new wave of hospital‐acquired infections such as emerging multidrug‐resistant Candida auris. We aimed to evaluate and estimate the global prevalence of coronavirus‐associated C. auris infection (CACa).

Methods

We searched related databases between December 2019 and April 2022 for studies that reported data about CACa. Meta‐analysis was performed using MedCalc software version 20.104 according to the DerSimonian and Laird method applying the random‐effects model. We evaluated heterogeneity using the χ²‐based Q statistic (significant for p‐value < .1) and the I² statistic (>75% indicative of ‘notable’ heterogeneity). Moreover, if possible, an odds ratio (OR) analysis was performed for eligible data.

Results

Our meta‐analysis includes ten eligible studies, including 1942 patients hospitalised with COVID‐19; 129 were C. auris cases. The overall pooled prevalence of CACa was estimated at 5.7%. The mortality rate of CACa was estimated at 67.849%. Hypertension was the most prevalent comorbidity (59.374%), followed by diabetes mellitus (52.898%) and cardiovascular diseases (31.392%). Men with a prevalence rate of 80.012% were 3.27 (OR) times more prone to getting infected by C. auris.

Conclusion

We concluded that the prevalence of C. auris infections decreased during the COVID‐19 pandemic and the prevalence gradient changed from Asia to America. Unfortunately, there are many descriptive studies with duplicate content in the field of epidemiology of C. auris infections which are increasing every day. We suggest further non‐descriptive studies to accurately establish the cause‐and‐effect relationships between C. auris and COVID‐19 infections.

Advances in Optical Sensors of N-Acetyl-β-d-hexosaminidase (N-Acetyl-β-d-glucosaminidase)

N-Acetyl-β-d-hexosaminidases (EC 3.2.1.52) are exo-acting glycosyl hydrolases that remove N-acetyl-β-d-glucosamine (Glc-NAc) or N-acetyl-β-d-galactosamine (Gal-NAc) from the nonreducing ends of various biomolecules including oligosaccharides, glycoproteins, and glycolipids. The same enzymes are sometimes called N-acetyl-β-d-glucosaminidases, and this review article employs the shorthand descriptor HEX(NAG) to indicate that the terms HEX or NAG are used interchangeably in the literature. The wide distribution of HEX(NAG) throughout the biosphere and its intracellular location in lysosomes combine to make it an important enzyme in food science, agriculture, cell biology, medical diagnostics, and chemotherapy. For more than 50 years, researchers have employed chromogenic derivatives of N-acetyl-β-d-glucosaminide in basic assays for biomedical research and clinical chemistry. Recent conceptual and synthetic innovations in molecular fluorescence sensors, along with concurrent technical improvements in instrumentation, have produced a growing number of new fluorescent imaging and diagnostics methods. A systematic summary of the recent advances in optical sensors for HEX(NAG) is provided under the following headings: assessing kidney health, detection and treatment of infectious disease, fluorescence imaging of cancer, treatment of lysosomal disorders, and reactive probes for chemical biology. The article concludes with some comments on likely future directions.

A Portable Droplet Magnetofluidic Device for Point-of-Care Detection of Multidrug-Resistant Candida auris

Candida auris is an emerging multidrug-resistant fungal pathogen that can cause severe and deadly infections. To date, C. auris has spurred outbreaks in healthcare settings in thirty-three countries across five continents. To control and potentially prevent its spread, there is an urgent need for point-of-care (POC) diagnostics that can rapidly screen patients, close patient contacts, and surveil environmental sources. Droplet magnetofluidics (DM), which leverages nucleic acid-binding magnetic beads for realizing POC-amenable nucleic acid detection platforms, offers a promising solution. Herein, we report the first DM device—coined POC.auris—for POC detection of C. auris. As part of POC.auris, we have incorporated a handheld cell lysis module that lyses C. auris cells with 2 min hands-on time. Subsequently, within the palm-sized and automated DM device, C. auris and control DNA are magnetically extracted and purified by a motorized magnetic arm and finally amplified via a duplex real-time quantitative PCR assay by a miniaturized rapid PCR module and a miniaturized fluorescence detector—all in ≤30 min. For demonstration, we use POC.auris to detect C. auris isolates from 3 major clades, with no cross reactivity against other Candida species and a limit of detection of ∼300 colony forming units per mL. Taken together, POC.auris presents a potentially useful tool for combating C. auris.

Reverse Transcription-Quantitative Real-Time PCR (RT-qPCR) Assay for the Rapid Enumeration of Live Candida auris Cells from the Health Care Environment

Ongoing health care-associated outbreaks of the multidrug-resistant yeast Candida auris have prompted the development of several rapid DNA-based molecular diagnostic tests. These tests do not distinguish between live and dead C. auris cells, limiting their use for environmental surveillance and containment efforts. We addressed this critical gap by developing a reverse transcription (RT)-quantitative real-time PCR (RT-qPCR) assay to rapidly detect live C. auris in health care environments. This assay targeted the internal transcribed spacer 2 (ITS2) ribosomal gene by obtaining pure RNA followed by reverse transcription (ITS2 cDNA) and qPCR. ITS2 cDNA was not detectable in bleach-killed cells but was detectable in heat- and ethanol-killed C. auris cells. The assay was highly sensitive, with a detection limit of 10 CFU per RT-qPCR. Validation studies yielded positive cycle threshold (CT) values from sponge matrix samples spiked with 102 to 105 CFU of live C. auris, while dead (bleach-killed) C. auris (105/mL) or other live Candida species (105/mL) had no CT values. Finally, 33 environmental samples positive for C. auris DNA but negative by culture were all negative by RT-qPCR assay, confirming the concordance between culture and the PCR assay. The RT-qPCR assay appears highly reproducible, robust, and specific for detecting live C. auris from environmental samples. The Candida auris RT-qPCR assay could be an invaluable tool in surveillance efforts to control the spread of live C. auris in health care environments.