Sind die klassischen Methoden zur mykologischen Diagnostik noch „State-of-the-Art“?

[Do the new molecular assays-microarray and realtime polymerase chain reaction-for dermatophyte detection keep what they promise?]

In this study, a novel real-time polymerase chain reaction (PCR) assay (DermaGenius®2.0, PathoNostics BV, Maastricht, The Netherlands) and a recently developed microarray test (EUROArray Dermatomycosis, Euroimmun, Lübeck, Germany) were evaluated regarding their diagnostic specificity to identify dermatophyte DNA. The tests were compared to conventional methods and sequencing. The microarray Dermatomycosis test allows the detection of 50 dermatophytes and definitive identification of 23 dermatophyte species, 6 yeasts and moulds combined in one test. In comparison, real-time PCR is able to identify 11 dermatophytes and one yeast at the species level. Using the EUROArray, 22 out of 24 dermatophyte species were correctly identified. Using real-time PCR, 9 out of the 11 different dermatophytes included in the test kit were correctly identified. Both molecular tests for detection and differentiation of dermatophytes are useful tools for daily clinical practice. The real-time PCR test does not detect as many species, and specificity is slightly lower. However, real-time PCR is a very fast and easy to perform test, especially since no post-PCR step is necessary. Real-time PCR detects the most frequent dermatophytes like T. rubrum, T. interdigitale, and M. canis without any problems. The EUROArray is more elaborate to perform in the lab, due to the hybridization step. However, the EUROArray shows higher specificity and can detect a much broader range of causative agents, including rare species, in dermatomycology.

Trichophyton mentagrophytes - a new genotype of zoophilic dermatophyte causes sexually transmitted infections

BACKGROUND

A new genotype of the zoophilic fungal species Trichophyton (T.) mentagrophytes was recently described in two studies. It was isolated from three patients who had visited Southeast Asia and one patient who had visited Egypt. In contrast to these studies, we have observed a number of cases with the dimensions of an epidemic outbreak.

PATIENTS AND METHODS

At the University Hospital Charité Berlin, 43 patients, mostly suffering from highly inflammatory, painful and persistent infections of the pubogenital region were observed between January 2016 and July 2017. Mycological examination was performed with fungal culture and sequencing of the ITS (internal transcribed spacer) region of the ribosomal DNA. Three additional genomic regions were spot-checked.

RESULTS

In 37 of the cases, a new genotype of T. mentagrophytes (referred to here as T. mentagrophytes VII) was isolated as the etiological agent, and sequencing revealed identical sequences for all isolates. Most of the infected patients had no history of travel, and only two patients reported contact with animals.

CONCLUSIONS

The new genotype clustered phylogenetically among the strains of the zoophilic species T. mentagrophytes with four different DNA markers. While human-to-human transmission of zoophilic dermatophytes is rare, transmission via sexual contact seemed to be quite effective here.