Trichophyton mentagrophytes ITS genotype VII infections among men who have sex with men in France: An ongoing phenomenon

Abstract

Background: Trichophyton mentagrophytes ITS genotype VII (TMVII) has recently been identified in France as the causative agent of dermatophyte infections transmitted during sexual activity among men who have sex with men (MSM).

Objectives: Our objective was to provide new insights into the epidemiology, clinical presentation and treatment of TMVII infections based on cases diagnosed from October 2022 to September 2023 in three medical mycology laboratories in Paris. Additionally, we aimed to perform molecular characterization of TMVII strains collected in Paris, as well as in Switzerland.

Methods: We identified all isolates from skin and hair belonging to the T. mentagrophytes complex by sequencing the ITS region. For isolates corresponding to TMVII, clinical data were retrieved from medical records. For all available TMVII strains that we isolated since January 2021, we sequenced tef1α and tubb and determined the MAT locus idiomorph.

Results: We identified 32 cases of TMVII Infections. All cases occurred in men, 30 of whom reported having sex with men. Fifteen cases were sporadic cases including four among sex workers. The other 17 cases belonged to a single cluster involving a tantric masseur who infected 15 clients and his roommate. The median time from massage to lesion onset was 16 [2-52] days. Except for one patient, all other patients received systemic antifungal treatment with terbinafine. We observed five patients whose cultures remained positive even after 3-4 weeks of treatment and five patients experienced a relapse of the infection after discontinuing antifungal treatment. All French isolates exhibited identical tef1α and tubb sequences, as well as the same MAT idiomorph locus. They displayed variations in the tef1α sequence compared to isolates from Switzerland and the Czech Republic.

Conclusions: We confirm the active circulation of TMVII among MSM in France, which is associated with challenges in diagnosis, treatment and prevention.

FIGURE 1

Clinical appearance of sporadic cases of Trichophyton mentagrophytes ITS genotype VII infections. (a) Inflammatory lesion of the moustache (kerion), (b) erythemato‐squamous and nodular lesions of the pubis, (c) and (d) worsening of buttock lesions after 3 weeks of treatment with topical ketoconazole, with the appearance of nodules and pustules.

FIGURE 2

Clinical lesions in a cluster of 17 Trichophyton mentagrophytes ITS genotype VII infections linked to a single masseur. (a, b) Erythemato‐squamous circinate lesions on the torso and elbow of the masseur, (c–e) erythemato‐squamous circinate lesions on the buttocks in three different clients of the masseur, (f) exudative lesion on the finger of a client and (g, h) low inflammatory lesions on the buttocks in two patients who relapsed after discontinuation of treatment.