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Dermatophytes are filamentous keratinophilic fungi responsible for superficial fungal diseases involving the skin, hair, or nails. On the basis of the site of the lesions, conditions are called tinea corporis, [...]

Trichophyton indotineae is an emerging species of the Trichophyton mentagrophytes complex (TMC), responsible for an epidemic of widespread hairless skin infections that is frequently (50–70%) resistant to terbinafine. In order to initiate appropriate treatment as quickly as possible without waiting for culture positivity (10–15 days) and molecular identification from the strain, we developed a dual quantitative PCR (qPCR) for the direct detection of T. indotineae in clinical samples. We first designed a T. indotineae -specific qPCR assay (TI -qPCR) targeting a single specific polymorphism in the internal transcribed spacer region. Although none of the 94 non-dermatophyte and 7 dermatophyte species were amplified, this TI -qPCR allowed amplification of other TMC species at a lower yield. With equal amounts (0.1 ng) of DNA per reaction, the mean quantitative cycle (Cq) values for T. indotineae and non- indotineae TMC were 27.9 (±0.1) and 38.9 (±0.3), respectively. Therefore, we normalized this assay against a previously validated pan-dermatophyte qPCR assay (PD-qPCR) and relied on the ΔCq [(TI -qPCR) − (PD-qPCR)] to identify T. indotineae versus other TMC species. Dual assay was validated using 86 clinical samples of culture-confirmed T. indotinea and 19 non- indotineae TMC cases. The mean ΔCq for non- indotineae TMC was 9.6 ± 2.7, whereas the ΔCq for T. indotinea was −1.46 ± 2.1 (P  < .001). Setting the ΔCq at 4.5 as a cutoff value resulted in 100% specificity for the detection of T. indotineae. This dual qPCR assay quickly detects T. indotineae from skin scrapings, aiding in early diagnosis and treatment for patients with suspected infection. [ABSTRACT FROM AUTHOR]

Tinea capitis (TC) is still a frequent dermatophytosis in France, both autochthonous and imported. A nationwide retrospective survey was performed and a total of 4395 TC cases were recorded within 36 French mycology laboratories during a 6-year period. TC is a disease that occurs in childhood with 85% of the cases occurring before 10 years old and 94% before the age of 15. Anthropophilic origin was predominant with 779 cases of Trichophyton tonsurans (32.6%), 738 cases of Trichophyton soudanense/T. violaceum (31%), and 445 cases of Microsporum audouinii (19.2%). Of note, T. tonsurans represents more than 80% of the cases in the French West Indies (Martinique and Guadeloupe). By contrast, zoophilic species were less prevalent with mainly M. canis (10.3%) confirming the shift from zoophilic to anthropophilic species observed in many centers during the last decades. During this survey, diagnosis methods were also collected. Most labs had a classical process for the diagnosis: microscopic direct examination associated to cultures on Sabouraud and Sabouraud-cycloheximide media (incubated between 25 ± 5°C for at least 3 weeks) in all laboratories. Identification of the causal dermatophyte was performed by microscopic and macroscopic examination of the cultures in 100% of the labs, with various specific culture media available when fructification was insufficient (mainly malt or potato-dextrose agar, or Borelli medium). New techniques were also implemented with the introduction of MALDI-TOF mass spectrometry identification in more than two third of the labs, and molecular identification available if necessary in half of the labs. [ABSTRACT FROM AUTHOR]

Tinea capitis (TC) is a highly contagious fungal infection of the scalp due to dermatophytes in children. To obtain information on the epidemiology of TC in the urban area of Paris, we analysed the microbiological results of 3090 patients seen with suspected TC from October 2010 to September 2015 at Saint Louis hospital, Paris, France. A peak of TC was observed in 3-6 year-old children, followed by a progressive decrease until 16 years of age. Of the 1311 positive cultures, 95% (1246) yielded one of the three anthropophilic species [Trichophyton tonsurans (33.5%), Trichophyton soudanense (38.3%), or Microsporum audouinii (28.2%)].When considering one TC case per family, we observed a significant increase of T. tonsurans (P = .018) during these 5 years. The increase was more pronounced (P = .0047) in patients of West-African descent (n = 666), and was at the expense of M. audouinii and T. soudanense. On the other hand, the Caribbean patients (n = 85) remained predominantly (72.9%) infected by T. tonsurans. Our results show a better virulence of T. tonsurans over other species as already reported. Since T. tonsurans has not been reported in Africa, the infection of patients of West-African descent probably took place in the Paris area by exchanges with Caribbean patients. This increase of TC due to T. tonsurans was observed in the context of griseofulvin being the only licensed paediatric treatment for TC in France, which should deserve reappraisal because terbinafine may be more efficacious. [ABSTRACT FROM AUTHOR]

Althought Malassezia spp. have been involved in various pathologies, they are an integral part of the cutaneous, gut, oral, ears, nose and throat (ENT) mycobiota. Since Malassezia are difficult to grow in culture, unexhaustive molecular biology methods have been developed to detect them. The aim of the study was to evaluate an in-house pan-Malassezia quantitative polymerase chain reaction (panM-qPCR) on various clinical human samples and determine Malassezia burden in various human mycobiota. The panM-qPCR was designed to target the repeated 28S rDNA gene from all Malassezia species. We used the assay to quantify the Malassezia burden on 361 samples from 161 subjects (80 skin swabs from 10 healthy volunteers (HV), 13 samples from 2 seborrheic dermatitis patients (SD), 90 skin samples from 19 burned patients, 119 stool samples from 89 immunocompromised patients, 59 ENT samples from 41 patients). For HV, the amount of Malassezia was different according to the swabbed areas. Quantification cycle (Cq) in SD is lower than in HV. In burned patients, Cq was significantly lower compared to HV. In stool samples, 6.7% were positive for Malassezia spp. with a high Cq. For the ENT area, a higher proportion of positive specimens were detected in ear samples than in nose samples. Our findings emphasized the importance of qPCR, confirming elevated Malassezia spp. levels on individuals' faces and scalps, increased burden in SD patients and in severely burnt patients than in HV. The pan-MqPCR appears to be a promising tool for studying Malassezia in various human mycobiota., (© The Author(s) 2024. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology.)