Presumptive Zoonotic Kerion by Nannizzia gypsea: Case Report

Nannizzia gypsea (formerly Microsporum gypseum) belongs to geophilic dermatophytes, fungi involved in keratin degradation in the soil; however, they are also found in dogs and cats. Transmission to humans can occur directly by contact with soil, but indirect transmission via domestic animals is reported too. The exact source of the infection is usually difficult to assess and in most cases only hypothesised and rarely investigated. This case report describes a kerion caused by N. gypsea in a 2-year-old boy, where the contagion was probably secondary to domestic healthy carrier dogs. A “One-Health” approach involving human dermatologists and veterinarians, combined with the use of conventional and molecular-based techniques, allowed tracing of the epidemiological chain and managing of not only the treatment but also the prevention of a recurrence. The child's lesion began to regress after about 8 weeks of treatment with both systemic and topical therapy, while the dogs were given chlorhexidine and miconazole baths. No recurrences nor new infections occurred, demonstrating the effectiveness of the strategies used.

Diversity of Geophilic Dermatophytes Species in the Soils of Iran; The Significant Preponderance of Nannizzia fulva

A molecular epidemiology study was conducted between 2016 and 2017 by a network of collaborators from 12 provinces in the Islamic Republic of Iran. A total of 1484 soil samples from different habitats were screened for the presence of dermatophytes by using the hair baiting technique. The primary identification of isolates was carried out by amplification and MvaI restriction fragment length polymorphism (RFLP) of the internal transcribed spacers regions of ribosomal DNA (ITS-rDNA). The identifications, especially in the cases of isolates with unknown RFLP patterns, were confirmed by sequencing of the ITS-rDNA region. As a result, 256 isolates were recovered. The isolation rate was higher in soils with pH range 7.1–8.0, collected from animal habitats (n = 78; 34%) and parks and gardens (n = 75; 32%), geographically from Mazandaran Province (n = 115; 49.5%) and seasonally in the spring (n = 129; 50.4%), all of which were statistically significant (p < 0.05). The dermatophytes comprising five species of the two genera, viz., Nannizzia fulva (n = 214), N. gypsea (n = 34), Arthroderma quadrifidum (n = 5), A. gertleri (n = 2) and A. tuberculatum (n = 1), were isolated. The geophilic dermatophytes occurred in various soils from different parts of Iran; however, surprisingly, N. fulva emerged as the dominant species, outnumbering the common geophilic species of N. gypsea. For the definitive identification of soil inhabitant dermatophytes, DNA-based identification is strongly recommended.

Some correlations between the occurrence frequency of keratinophilic fungi and selected soil properties

The results of studies on the correlation between the occurrence frequency of keratinophilic fungi, including geophilic dermatophytes and chrysosporium, and soil properties are presented and discussed in the article. The fraction with 0 &lt; 0.02 mm content and the soil pH were the most significant ecological factors that determined the frequency of occurrence and the distribution of these fungi in the soil

Studies on the mycroflora colonizing keratin-bark-urea manure

The studies demonstrated the succession of physiologically differentiated communities of fungi that colonize the organic component of keratin-bark-urea manure. There were no records of any typical keralinolylic forms that represent geophilic dermatophytes and chrysospories.

Geophilic dermatophytes and other keratinophilic fungi in the nests of wetland birds

The frequency and species diversity of keratinophilic fungi in 38 nests of nine species of wetland birds were examined. Nine species of geophilic dermatophytes and 13 <em>Chrysosporium</em> species were recorded. <em>Ch. keratinophilum</em>, which together with its teleomorph (<em>Aphanoascus fulvescens</em>) represented 53% of the keratinolytic mycobiota of the nests, was the most frequently observed species. <em>Chrysosporium tropicum, Trichophyton terrestre</em> and <em>Microsporum gypseum</em> populations were less widespread. The distribution of individual populations was not uniform and depended on physical and chemical properties of the nests (humidity, pH).

Species diversity of keratinophilic fungi in various soil types

Keratinophilic fungi are a highly specialized, keratin-degrading ecological group. They live in natural environments, mostly in the keratinrich remains of dead animal in the soil. We investigated species diversity in four types of soils with different physico-chemical properties. The strain material was identified based on morphological characters. Different representatives of Chrysosporium and geophilic dermatophytes dominated depending on soil pH. Geophilic dermatophytes were represented by one species, Trichophyton ajelloi, and the Chrysosporium group was represented by Chrysosporium keratinophilum. The frequency of Trichophyton ajelloi increased with an increase in pH, and it reached the maximum in strongly acidic soil (podzol), unlike the Chrysosporium group. The frequency of Chrysosporium keratinophilum was positively correlated with the content of humus, nitrogen, CaCO3 and phosphorus in the soils.