German-Wide Analysis of the Prevalence and the Propagation Factors of the Zoonotic Dermatophyte Trichophyton benhamiae

Abstract

For about 10 years, a new variant of the pathogen Trichophyton (T.) benhamiae has appeared in Germany, characterized by a previously unobserved culture phenotype with a strong yellow reverse. A few studies suggest that this new variety is now the most common zoophilic dermatophyte in Germany. The guinea pig is the main carrier. Exact prevalence measurements are not yet available. Thus, the aim of our ongoing study was to collect data on the frequency and geographic distribution of the pathogen and its phenotypes (white and yellow) in humans and guinea pigs throughout Germany. Our former studies have already shown that animals from large breeding farms are particularly heavily affected. In contrast to this, 21 small, private breedings were sampled and husbandry conditions recorded. This placed us in a position to identify propagation factors and to give recommendations for containment. For animals from private breedings, we detected T. benhamiae with a prevalence of 55.4%, which is a reduction of nearly 40% compared with animals from large breeding farms. As risk factors, we identified the type of husbandry and the contact to other breedings. Furthermore, certain animal races, like Rex guinea pigs and races with long hair in combination with curls were predestined for colonization with T. benhamiae due to their phenotypic coat characteristics. A prevalence for infections with T. benhamiae of 36.2% has been determined for symptomatic pet guinea pigs suspected of having dermatophytosis and is comparable to the study of Kraemer et al. showing a prevalence of 34.9% in 2009 in Germany. The prevalence in humans is stable with about 2–3% comparing the data of 2010–2013 and 2018 in Thuringia. The new type of T. benhamiae was by far the most frequent cause in all settings.

Taxonomy of the Trichophyton mentagrophytes/T. interdigitale Species Complex Harboring the Highly Virulent, Multiresistant Genotype T. indotineae

“…indotineae . Berlin et al [ 30 ] also reported T . interdigitale from guinea pigs and hypothesized that these strains had a human origin from the breeders.…”

“…2), while three strains from animals belonged to T. interdigitale; none of the animal isolates was found in T. indotineae. Berlin et al [30] also reported T. interdigitale from guinea pigs and hypothesized that these strains had a human origin from the breeders.…”

Pilzinfektionen der Haut und Nägel

“…Diese Nagetiere tragen den für Deutschland erst seit 2008 bekannten zoophilen Dermatophyten T . benhamiae zu etwa 50 % im Fell [ 1 ]. In der Folge werden momentan deutlich mehr Kinder und Jugendliche, jedoch auch Erwachsene mit Tinea corporis, Tinea faciei und Tinea capitis durch T .…”

A Polyphasic Approach to Classification and Identification of Species within the Trichophyton benhamiae Complex

“…Genetically, these phenotypic variants seem to be indistinguishable [5,8,15]. In the last few decades, T. benhamiae has also become a more prevalent agent of dermatophyte infection in several European regions [16][17][18][19]. It is striking to see that human infection by T. benhamiae was barely on the radar a decade ago, while it is becoming more and more commonplace nowadays [2,18,19].…”