[Diagnosing dermatomycoses in a clinical mycology laboratory: guidelines proposed by the Czech Society for Medical Microbiology Working Group on Mycology].

This draft of guidelines for the laboratory diagnosis of dermatomycoses was developed based on discussion among members of the Czech Society for Medical Microbiology Working Group on Mycology. The document Guidelines for the Laboratory Diagnosis of Dermatomycoses was published for discussion on the Czech Society for Medical Microbiology website on 23 March 2020. Until recently, recommendations concerning this area of laboratory diagnosis in mycology were only limited to information in manuals and no comprehensive and systematic document concerning these issues was available. In an effort to fill the gap, members of the working group developed recommendations covering various laboratory aspects of mycology, from obtaining a proper history, to adequate sampling techniques, sample analyses using conventional microscopy and culture techniques, to interpretation of results. Additional information was on the diagnostic potential of novel, modern technology, in particular molecular genetic methods and mass spectrometry. The recently developed European standards for testing the susceptibility of dermatophytes to antifungals were also included in the recommendations. The document will be regularly updated based on new findings.

An Outbreak of Trichophyton quinckeanum Zoonotic Infections in the Czech Republic Transmitted from Cats and Dogs.

Trichophyton quinckeanum, a zoophilic dermatophyte mostly known as the causative agent of rodent favus, is relatively rarely reported to cause human infections. Indeed, no infections were detected in Czechia between 2012 and 2015 despite routine verification of species identification by ITS rDNA sequencing. By contrast, 25 human and 11 animal cases of infection were documented from December 2016 to December 2020 and the rates tended to grow every following year. Interestingly, most of the cases were reported in the Olomouc region, suggesting a local outbreak. We bring the evidence that human T. quinckeanum infections are most commonly contracted from infected cats or, less frequently, dogs. Although rodents or contaminated soil and environment could be the source of infection to cats and dogs, the occurrence of infections in multiple animals in the same household suggests direct transmission among animals. Confirmation of the identification by molecular methods is highly recommended due to morphological similarity with T. mentagrophytes/T. interdigitale. Antifungal susceptibility testing of isolates to eight antifungals was performed using EUCAST methodology (E.Def 11.0). Among the tested antifungals, terbinafine, amorolfine, ciclopirox and efinaconazole were most potent in vitro and elevated minimum inhibitory concentrations were obtained for fluconazole and ketoconazole.

The Oomycete Pythium oligandrum Can Suppress and Kill the Causative Agents of Dermatophytoses.

Pythium oligandrum (Oomycota) is known for its strong mycoparasitism against more than 50 fungal and oomycete species. However, the ability of this oomycete to suppress and kill the causal agents of dermatophytoses is yet to be studied. We provide a complex study of the interactions between P. oligandrum and dermatophytes representing all species dominating in the developed countries. We assessed its biocidal potential by performing growth tests, on both solid and liquid cultivation media and by conducting a pilot clinical study. In addition, we studied the molecular background of mycoparasitism using expression profiles of genes responsible for the attack on the side of P. oligandrum and the stress response on the side of Microsporum canis. We showed that dermatophytes are efficiently suppressed or killed by P. oligandrum in the artificial conditions of cultivations media between 48 and 72 h after first contact. Significant intra- and interspecies variability was noted. Of the 69 patients included in the acute regimen study, symptoms were completely eliminated in 79% of the patients suffering from foot odour, hyperhidrosis disappeared in 67% of cases, clinical signs of dermatomycoses could no longer be observed in 83% of patients, and 15% of persons were relieved of symptoms of onychomycosis. Our investigations provide clear evidence that the oomycete is able to recognize and kill dermatophytes using recognition mechanisms that resemble those described in oomycetes attacking fungi infecting plants, albeit with some notable differences.

[Practical knowledge in fungal diagnosis in some biological materials]. / Praktické poznatky v mykologické diagnostice u nekterých biologických materiálu.

The article deals with certain problematic issues associated with routine laboratory diagnosis of mycoses from secretions and samples taken from the respiratory tract and maxillary sinuses as well as samples of skin and skin appendages. The text is based on both the author's own long-term experience and experience gained from cooperation with other laboratories. To improve the detection of filamentous fungi in lower respiratory tract secretions, it is recommended to use 0.5 mL of the material for individual culture media. In both secretions and other biological material, the role of microscopic examination is stressed. In many cases, this may also be the only reliable laboratory procedure. Detection of filamentous fungi should be interpreted in close cooperation with clinicians, especially in order to obtain history data. These are particularly important in the diagnosis of endemic mycoses. Equivocal or unusual findings should be verified by repeated laboratory tests.

Rare and new etiological agents revealed among 178 clinical Aspergillus strains obtained from Czech patients and characterized by molecular sequencing.

A collection of 178 Aspergillus isolates, recovered from Czech patients, mostly from 2007-2011, was subjected to multilocus DNA sequence typing using the ITS region, ß-tubulin, and calmodulin genes. An unusually wide spectrum of etiologic agents that included 36 species of Aspergillus is discussed in the context of recent taxonomic and clinical reports. Invasive aspergillosis (IA), onychomycosis, and otitis externa were the predominant clinical entities. Five cases due to species newly proven as etiologic agents of human mycoses, as well as cases with unique clinical manifestations caused by unusual agents are discussed in more detail. Three species (i.e., A. insulicola, A. westerdijkiae and A. tritici) were identified as the confirmed etiologic agents of non-dermatophytic onychomycosis. Emericella rugulosa was recovered from a premature newborn with a fatal necrotising disseminated infection and is reported for only the second time as the cause of IA. Furthermore, we document the first infection due to A. calidoustus in a patient with chronic granulomatous disease. The infection manifested as a latent brain aspergilloma with an unusual clinical-laboratory finding. In addition to the well-known agents of human mycosis, several rarely isolated or poorly documented species were identified. An undescribed cryptic species related to A. versicolor was found to be common among isolates linked to proven and probable onychomycosis. An isolate representing A. fresenii, or an unnamed sister species, were causal agents of otomycosis. Three well defined, and tentative new species belonging to section Cervini, Candidi and Aspergillus (Eurotium spp.), were associated with cases of probable onychomycosis.

Phaeohyphomycosis and onychomycosis due to Chaetomium spp., including the first report of Chaetomium brasiliense infection.

Chaetomium species have been rarely described as aetiological agents of invasive and dermatomycotic infections in humans. The majority of cases have been reported within the last two decades. Treatment failed in most of these cases. In this paper we present two cases in which Chaetomium spp. can be clearly identified as an aetiological agent in pathological conditions. In the first report, we describe a new aetiological agent, Chaetomium brasiliense, which was implicated in a case of otitis externa in a patient with spinocellular carcinoma basis cranii. The patient had been repeatedly treated for relapsing otitis externa and had previously undergone surgery several times for otitis media. The fungal aetiology was confirmed by repeated positive culture and histologic studies. The second case involved onychomycosis with strikingly brown nail discoloration due to Chaetomium globosum in an otherwise healthy patient. The nail lesion was successfully cured by oral terbinafine. The determination of both species was supported by sequencing of rDNA regions. The morphological aspect of Chaetomium spp. identification is also discussed. In vitro antifungal susceptibility tests demonstrated that both isolates were susceptible to terbinafine and azole derivates except fluconazole. Amphotericin B was effective only against the C. brasiliense strain. We review the literature to summarize clinical presentations, histologic findings, and treatment strategies.