The emerging threat from Candidozyma auris (previously Candida auris): infection prevention and control challenges

I’ve written this blog about the emerging threat posed by Candidozyma auris in preparation for our first Insight Webinar, led by Dr Areej Al-Ali, on Wednesday this week. You can register for the webinar here, and see further details about our Insight Webinars here.

Candidozyma auris (recently reclassified from Candida auris following a taxonomic revision in 2023) has rapidly become one of the most talked-about microbial threats in healthcare in recent years. Its unique biology, multidrug resistance, capability to cause serious infection, and ability to spread in hospitals pose substantial and evolving challenges for IPC teams globally.

This blog provides some key updates on the microbiology, epidemiology, and IPC challenges related to C. auris.

1. Taxonomic shift

In 2024, C. auris was formally reassigned as the type species of the new genus Candidozyma to reflect its distant phylogenetic relationship from traditional Candida species. This affects laboratory workflows, diagnostic algorithms, and the interpretation of historical literature which still uses “Candida auris”. This reclassification underscores the organism’s uniqueness, both genetically and clinically, and reinforces the need for accurate species identification using biochemical, proteomic, or molecular methods.

2. Epidemiology: a rapidly expanding global threat

Since its first identification in Japan in 2009, C. auris has spread to somewhere between 40–61 countries across six continents, reflecting a pattern of near-simultaneous global emergence. Asia remains a major epicentre, with sustained transmission and multiple clades reported in India, China, Pakistan, South Korea, and Japan. In the Americas, the United States has seen a sharp rise with cases tripling between 2020 and 2021, while several Latin American countries continue to battle healthcare-associated outbreaks. Significant but often under‑reported activity is emerging across Africa, especially in South Africa, where C. auris has become an important cause of ICU candidemia. The Middle East, including Kuwait, the UAE, and Saudi Arabia, has documented prolonged outbreaks linked to high colonization pressure and environmental persistence. Australia has detected repeated introductions, primarily linked to international transfers, though endemic spread is not yet established. Across all WHO regions, outbreaks share common features: multidrug resistance, delayed detection, misidentification, and persistent environmental reservoirs, cementing C. auris’ status as a global threat!

3. Biological features that drive IPC challenges

C. auris has a number of biological features that drive IPC challenges:

• Environmental persistence. C. auris colonises skin, survives for months on surfaces, and contaminates both high touch and distal environmental sites (e.g., bedrails, door handles). It also forms robust, adherent biofilms that resist routine cleaning and antifungal treatments.
• Multidrug resistance. C. auris is often resistant to multiple antifungal classes, including azoles and, increasingly, echinocandins. This limits therapeutic options and elevates the importance of preventing transmission.
• Misidentification risk. The organism is frequently misidentified by conventional diagnostics, requiring MALDI TOF with updated databases or molecular assays for correct identification

4. Transmission dynamics in healthcare settings

Transmission occurs primarily through contact via the hands of healthcare providers, contaminated surfaces, shared medical equipment, and direct/indirect contact with colonised or infected patients. Outbreaks often follow the introduction of colonised individuals from other healthcare facilities or international transfers. Notably, even well established IPC systems struggle to contain transmission once environmental contamination becomes widespread. There is some hope of containment through! For example, a study of a major outbreak demonstrated that enhanced surveillance and rigorous environmental cleaning significantly reduced hospital acquired infection incidence, from 0.37 to 0.04 cases per 1,000 patient days. Important to note here though that C. auris was not eliminated, continuing to be detected at a low level once the outbreak was contained.

5. Key IPC challenges

• Early identification and screening. Updated UK guidance emphasises expanded screening protocols, including body site specific sampling and clade typing. High risk admissions, such as patients previously hospitalised abroad, those with prolonged ICU stays, or individuals with extensive device use, should be prioritised for screening.
• Isolation and cohorting. Isolation of colonised or infected patients, with dedicated toilet facilities and equipment, remains essential. Cohorting may be used when isolation capacity is exceeded, though this increases logistical complexity.
• Environmental cleaning and disinfection. There are some questions over the effectiveness of commonly used hospital disinfectants, particularly quaternary ammonium compounds (QACs), against C. auris. In the USA, EPA List P approved disinfectants or chlorine based agents are recommended. In the UK, the guidance recommends chlorine-based disinfectants – although others such as peracetic acid have been shown to be effective too. Cleaning and disinfection when patients are discharged and daily environmental disinfection, especially of mobile and shared equipment, are essential to interrupt transmission chains. Biofilm formation on medical devices (e.g., catheters) contributes to persistence and reduced susceptibility to antifungals.
• Communication across the care pathway. Inter-facility communication during patient transfer is crucial to prevent onward spread. Standardised C. auris status reporting is strongly recommended by public health agencies around the world.
• Outbreak management and lessons learned. Multiple large-scale outbreaks around the world highlight several recurring themes. Delayed detection leads to entrenched environmental contamination. Insufficient cleaning and disinfection quality monitoring undermines outbreak control. Under-resourced IPC teams struggle with sustained intensive interventions. Lack of national surveillance systems hampers trend detection and cross facility learning.

6. Future directions

It seems certain now that C. auris will emerge eventually in all parts of the world (it’s already arrived in most!). Future efforts to combat C. auris will hinge on:

• strengthening global surveillance, including wider use of genomic sequencing and environmental screening, to detect transmission earlier and understand clade specific risks;
• advancing rapid and accurate diagnostics such as updated MALDI TOF MS, point of care molecular tools, and metagenomic methods to reduce misidentification;
• accelerating development of novel antifungals, vaccines, and immunotherapies alongside robust stewardship programmes;
• investing in next generation environmental control technologies, from validated no touch disinfection systems to smart auditing tools and antifungal resistant surface materials;
• enhancing IPC workforce capacity through global training platforms, standardised interfacility communication, and early warning frameworks;
• and expanding research into ecological and climate driven factors influencing emergence, all underpinned by coordinated international policy alignment and One Health collaboration to prevent the establishment of new reservoirs and curb global spread.

7. Summary

C. auris represents a ‘perfect storm’ of IPC challenges: environmental persistence, multidrug resistance, diagnostic ambiguity, and a high capacity for sustained healthcare associated transmission. Effective control relies on:

• Early identification and rigorous screening
• High quality environmental cleaning and disinfection with active oversight
• Standardised communication across facilities
• Adequate resourcing of IPC teams
• Continuous professional development and updated evidence-based guidance

As global case numbers continue to rise, coordinated and science driven IPC strategies will remain our strongest defence against this emerging global threat.