Sexually transmitted Trichophyton mentagrophytes genotype VII: molecular, pathogenic, human interaction surveillance and comparative indicators of a potentially new endemic threat.
Saleem Ahmad & Muhammad Nauman Aftab • Diagnostic microbiology and infectious disease • 2026
Trichophyton mentagrophytes genotype VII has emerged as a sexually transmitted fungal pathogen with escalating endemic potential driven by sexual and travel-associated transmission, emerging terbinafine treatment failures, and cryptic transmission within dense social networks, particularly among men who have sex with men.
Key Findings
Background
Trichophyton mentagrophytes genotype VII (TMVII) has been identified as a significant sexually acquired fungal pathogen triggering severe, inflammatory skin responses.
TMVII originates from animal (zoonotic) sources but has successfully integrated into human intimate networks
Notable outbreaks have occurred across European and North American continents
Transmission is particularly trending among men who have sex with men (MSM)
This trend has significantly increased during the last few years
Results
Molecular surveillance using ITS region sequencing can distinguish TMVII from other closely related species.
Differentiation is achieved via limited diagnostic single nucleotide polymorphisms (SNPs)
Core-genome analysis reveals diversity and specific host adaptation
TMVII possesses a specialized arsenal of keratin-degrading proteases (MEP1-4, SUB6)
These molecular tools enable identification of this pathogen from related dermatophytes
Results
Data from 2022 to 2026 suggest escalating endemic potential of TMVII driven by sexual and travel-associated transmission.
Transmission routes include both sexual contact and travel-associated spread
Emerging terbinafine treatment failures have been documented
Cryptic transmission within dense social networks threatens to establish TMVII as a chronic endemic pathogen
The period of surveillance covered approximately four years (2022–2026)
Results
TMVII lesions are more severe than common tinea infections and require prolonged systemic therapy.
Lesions are described as 'intensely inflamed'
Treatment typically requires three to eight weeks of systemic therapy
This duration is notably longer than that required for common tinea infections
The inflammatory response is characterized as severe compared to typical dermatophyte infections
Results
Emerging terbinafine treatment failures represent a significant clinical threat in managing TMVII infections.
Terbinafine is a standard antifungal treatment for dermatophyte infections
Treatment failures with terbinafine have been observed in TMVII cases
These failures, combined with cryptic transmission, threaten to establish TMVII as a 'devastating chronic endemic'
The authors describe this as contributing to potentially 'widespread intractable transmission'
Conclusions
The authors identify an urgent need for clinical awareness, enhanced diagnostic screening, and proactive public health interventions to address TMVII transmission.
Rising global cases have been documented alongside increased transmission via travel and contact
The authors call for 'urgent clinical awareness' and 'enhanced diagnostic screening'
Proactive public health interventions are described as necessary to prevent widespread intractable transmission
The authors state 'addressing this escalating threat is the need of the hour'
What This Means
This research describes Trichophyton mentagrophytes genotype VII (TMVII), a type of fungus that originally came from animals but has adapted to spread between humans through sexual contact. Unlike typical ringworm or athlete's foot, TMVII causes severely inflamed skin infections that are much harder to treat, requiring weeks of oral antifungal medication. The fungus has been spreading notably among men who have sex with men in Europe and North America, with cases increasing significantly between 2022 and 2026.
The research highlights two particularly concerning trends: the emergence of treatment failures with terbinafine (a commonly used antifungal drug), and the ability of the fungus to spread without obvious symptoms within dense social networks (called 'cryptic transmission'). The authors used genetic analysis techniques, including sequencing of specific DNA regions and whole-genome comparisons, to characterize how this pathogen differs from related fungi and how it has adapted to infect humans, including through specialized enzymes that break down skin proteins.
This research suggests that TMVII could become an established, difficult-to-control endemic infection if public health measures are not taken. The combination of drug resistance, sexual transmission, and international travel creates conditions for this fungus to spread globally. The authors argue for better diagnostic tools, increased awareness among healthcare providers, and targeted public health responses — particularly in communities where transmission is occurring — to prevent this emerging pathogen from becoming a widespread, chronic health problem.
Saleem Ahmad, Muhammad Nauman Aftab. (2026). Sexually transmitted Trichophyton mentagrophytes genotype VII: molecular, pathogenic, human interaction surveillance and comparative indicators of a potentially new endemic threat.. Diagnostic microbiology and infectious disease. https://doi.org/10.1016/j.diagmicrobio.2026.117427