News|Articles|April 18, 2025

Candida auris Epidemiology and Resistance Mechanisms Challenge Antifungal Treatment

Author(s)Sophia Abene

Six hundred thirty-seven cases in England, 4514 US clinical cases in 2023, and only 3 late‑stage antifungal drugs reveal surveillance and treatment gaps.

In a recent Nature editorial, C auris is highlighted as an emerging multidrug‑resistant yeast that has drawn urgent attention from global and UK health authorities amid rising outbreaks and antifungal resistance. A pathogen once obscure, it now symbolizes the broader crisis in fungal infections driven by scientific gaps, diagnostic delays, and agricultural practices.1

Since its discovery in 2009, C auris has rapidly spread to more than 60 countries. New data from the UK Health Security Agency (UKHSA) show that England reported 637 cases between 2013 and 2024, with 178 occurring in 2024 alone, the highest annual count to date. Most detections were colonizations, but the yeast can cause invasive infections with high mortality in immunocompromised patients.2

Treatment is challenging because C auris frequently resists azoles, like fluconazole, echinocandins, and polyenes, with resistance arising intrinsically or during therapy. In 2022, the WHO designated C auris a critical priority pathogen, a status previously limited to drug‑resistant bacteria.1

The uptick in C auris cases in England, particularly after COVID‑19 travel restrictions lifted, has been linked to prolonged hospital outbreaks that exposed lapses in routine screening, species‑level identification, and reporting. In response, UKHSA updated its guidance and, beginning April 2025, will require all diagnostic labs to notify on C auris cases.2

What You Need To Know

C auris has spread to over 60 countries since its discovery, with rising infection rates and mortality, particularly among immunocompromised individuals.

The pathogen’s resistance to multiple classes of antifungal drugs and its evolving mechanisms of resistance highlight the need for treatment strategies and better surveillance.

Environmental factors, including the use of fungicides in agriculture, are contributing to antifungal resistance, prompting regulatory changes to protect human health and preserve antifungal efficacy.

Globally, fungal infections now cause an estimated 3.8 million deaths per year, a figure that has nearly doubled over the past decade, yet they remain underfunded in antimicrobial resistance agendas. Fungal cells’ similarity to human cells complicates drug development. Resistance mechanisms in fungi differ from those in bacteria, so only three antifungal agents targeting priority pathogens are in late‑stage trials. The Nature editorial calls for multicenter clinical‑trial networks to advance these scarce candidates.1

Environmental factors amplify the threat. Agricultural azole fungicides resemble clinical antifungals, driving cross‑resistance. India has banned certain agricultural azoles, and both the US Environmental Protection Agency and EU agencies are tightening approval criteria and waste‑management standards to protect human‑use drugs.2

Recent reports in the American Journal of Infection Control documented a rise in C auris infections within Florida’s Jackson Health System, a large academic medical center. Over five years (2019–2023), clinical cases surged from just five in 2019 to 115 in 2023, a staggering 2,200% increase. Most infections were bloodstream-based, but in recent years, cases originating from soft tissue and bone also rose sharply. All sequenced isolates belonged to clade III (South African), showing resistance to fluconazole but susceptibility to echinocandins and amphotericin B.3 These findings reflect the broader national trend, with the CDC reporting 4,514 clinical C auris cases across the US in 2023 alone.4

References
1. High time to tackle drug-resistant fungal infections. Nature. April 15, 2025. Accessed April 18, 2025. doi:10.1038/d41586-025-01177-x
2. UK Health Security Agency. Increase in Candidozyma (Candida) auris reports in England, linked to hospital outbreaks. HPR. Updated March 31, 2025. Accessed April 18, 2025. https://www.gov.uk/government/publications/health-protection-report-volume-19-2025/hpr-volume-19-issue-3-news-27-march-2025#:~:text=From%20April%202025%2C%20C.,Protection%20(Notification)%20Regulations%202010
3. Rosa R, Baptista RP, Tran TT, et al. Changing Trends in the Sources and Volumes of Clinical Cultures with Candida auris at a Large Health System, 2019-2023. Am J Infect Control. March 17, 2025. Accessed April 18, 2025. doi:10.1016/j.ajic.2025.03.013
4. Tracking C. auris. CDC. December 9, 2024. Accessed April 18, 2025.
https://www.cdc.gov/candida-auris/tracking-c-auris/index.html?2023=2023

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