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

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.

Candida auris Updates: Outbreak Evaluation through Molecular Assays and Antifungal Stewardship-A Narrative Review

Candida auris was reported by the WHO as second to Cryptococcus neoformans, in the list of nineteen fungal priority pathogens, along with two species with a new nomenclature, Nakaseomyces glabrata (Candida glabrata) and Pichia kudriavzevii (Candida krusei). This novel classification was based on antifungal resistance, the number of deaths, evidence-based treatment, access to diagnostics, annual incidence, and complications and sequelae. We assessed which molecular assays have been used to diagnose Candida auris outbreaks in the last five years. Using "Candida auris; outbreak; molecular detection" as keywords, our search in PubMed revealed 32 results, from which we selected 23 original papers published in 2019-2024. The analyzed studies revealed that the detection methods were very different: from the VITEK® 2 System to MALDI TOF (Matrix-Assisted Laser Desorption Ionization-Time of Flight), NGS (Next-Generation Sequencing), WGS (Whole Genome Sequencing), and commercially available real-time PCR (Polymerase Chain Reaction) assays. Moreover, we identified studies that detected antifungal resistance genes (e.g., FKS for echinocandins and ERG11 for azoles). The analyzed outbreaks were from all continents, which confirms the capability of this yeast to spread between humans and to contaminate the environment. It is important that real-time PCR assays were developed for accurate and affordable detection by all laboratories, including the detection of antifungal resistance genes. This will allow the fast and efficient implementation of stewardship programs in hospitals.

Global characteristics and trends in research on Candida auris

Introduction

Candida auris, a fungal pathogen first reported in 2009, has shown strong resistance to azole antifungal drugs and has caused severe nosocomial outbreaks. It can also form biofilms, which can colonize patients' skin and transmit to others. Despite numerous reports of C. auris isolation in various countries, many studies have reported contradictory results.

Method

A bibliometric analysis was conducted using VOSviewer to summarize research trends and provide guidance for future research on controlling C. auris infection. The analysis revealed that the United States and the US CDC were the most influential countries and research institutions, respectively. For the researchers, Jacques F. Meis published the highest amount of related articles, and Anastasia P. Litvintseva's articles with the highest average citation rate. The most cited publications focused on clade classification, accurate identification technologies, nosocomial outbreaks, drug resistance, and biofilm formation. Keyword co-occurrence analysis revealed that the top five highest frequencies were for 'drug resistance,' 'antifungal susceptibility test,' 'infection,' 'Candida auris,' and 'identification.' The high-frequency keywords clustered into four groups: rapid and precise identification, drug resistance research, pathogenicity, and nosocomial transmission epidemiology studies. These clusters represent different study fields and current research hotspots of C. auris.

Conclusion

The bibliometric analysis identified the most influential country, research institution, and researcher, indicating current research trends and hotspots for controlling C. auris.