Aims: Dermatophytosis is a common superficial fungal infection of the skin and keratinised structures arising from it. Dermatophytes from the genera Trichophyton are a major causative agent of superficial mycoses. Terbinafine, an inhibitor of the squalene epoxidase (SQLE) enzyme, is the first line therapy used to treat trichophyton dermatophytosis. Alarmingly, there has been an increase in reported cases of terbinafine resistance globally. Despite this, antifungal susceptibility testing is currently not routinely used in Australia. As such, we aim to assess the prevalence of terbinafine resistant Trichophyton infection globally, elucidate the best method of testing for resistance and the most effective alternative treatment options available.
Methods: Systematic review of published human studies from 2000 up to 2023 of Terbinafine resistant Trichophyton Dermatophytosis with confirmed antifungal susceptibility testing and dermatophyte genotyping. Databases used include Ovid MEDLINE, Ovid Embase, Cochrane Database of Systematic Reviews, Cochrane’s Trials database and Global Health. Studies were limited to those published in English. This review was registered with PROSPERO. Identified cases were screened independently by two authors based on pre-determined criteria with any disagreements mediated by discussion and if needed, referral to a third author for mediation.
Results: 156 studies were included in this review which reported on the presence of terbinafine resistance with confirmed antifungal susceptibility testing as measured using the minimum inhibitory concentration (MIC). 33 studies comprising of 739 cases described the presence or absence of a SLQE mutation and correlated this to in-vitro terbinafine susceptibility. Moreover, 15 studies then correlated the presence or absence of a SLQE mutation with a stated MIC to the clinical manifestation or absence of terbinafine resistance.
Conclusions: Antifungal susceptibility testing is currently not routinely available in Australia despite growing emergence of the condition worldwide. This has significant implications for best practice locally in the treatment of emerging antifungal resistant dermatophytosis.