Spread of Antifungal-Resistant Trichophyton indotineae, United Kingdom, 2017–2024

Author: mycolabadmin
1/1/2025
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Summary

A dangerous fungal infection called Trichophyton indotineae is rapidly spreading across the United Kingdom, particularly among people with connections to South Asia. This infection causes stubborn skin rashes that don’t respond well to common antifungal treatments like terbinafine. The number of cases has skyrocketed, making up 38% of all dermatophyte infections by 2024, and doctors need to be aware of this emerging threat.

Background

Trichophyton indotineae is an emergent dermatophyte that causes difficult-to-treat superficial skin infections, initially reported in southern Asia starting in 2014. Many isolates exhibit in vitro resistance to terbinafine, and infections spread easily from person to person. Cases have been reported worldwide including Europe, Canada, and the United States.

Objective

To describe all cases of T. indotineae identified at the UK National Mycology Reference Laboratory during a 7-year period and determine the prevalence and spread of antifungal-resistant strains in the United Kingdom.

Results

157 cases of T. indotineae infection were identified, with 84.7% of patients having links to endemic areas. T. indotineae comprised 38% of all dermatophyte isolates received by the laboratory in 2024 up to July, increasing from 2% in 2018. In vitro resistance to terbinafine (MIC > 0.5 mg/L) was documented in 74.2% of tested isolates, and 31.8% of cases had documented treatment failure.

Conclusion

T. indotineae was introduced into the United Kingdom from endemic areas and is spreading substantially. Based on current trends, T. indotineae will likely become the predominant cause of tinea corporis in the United Kingdom. Clinicians and microbiology laboratorians should recognize this fungus as a predominant cause of tinea corporis.

Published in:Emerging Infectious Diseases,
Study Type:Descriptive Case Series,
Source: 10.3201/eid3101.240923; PMID: 39714510