Dermatophytoses represent a major health burden in animals and man. Zoophilic dermatophytes usually show a high specificity to their original animal host but a zoonotic transmission is increasingly recorded. In humans, these infections elicit highly inflammatory skin lesions requiring prolonged therapy even in the immunocompetent patient. The correct identification of the causative agent is often crucial to initiate a targeted and effective therapy. To that end, matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) represents a promising tool. The objective of this study was to evaluate the reliability of species identification of zoophilic dermatophytes using MALDI-TOF MS. The investigation of isolates from veterinary clinical samples suspicious of dermatophytoses suggests a good MALDI-TOF MS based identification of the most common zoophilic dermatophyte Microsporum canis. Trichophyton (T.) spp. usually achieved scores only around the cutoff value for secure species identification because of a small number of reference spectra. Moreover, these results need to be interpreted with caution due to the close taxonomic relationship of dermatophytes being reflected in very similar spectra. In our study, the analysis of 50 clinical samples of hedgehogs revealed no correct identification using the provided databases, nor for zoophilic neither for geophilic causative agents. After DNA sequencing, adaptation of sample processing and an individual extension of the inhouse database, acceptable identification scores were achieved (T. erinacei and Arthroderma spp., respectively). A score-oriented distance dendrogram revealed clustering of geophilic isolates of four different species of the genus Arthroderma and underlined the close relationship of the important zoophilic agents T. erinacei, T. verrucosum and T. benhamiae by forming a subclade within a larger cluster including different dermatophytes. Taken together, MALDI-TOF MS proofed suitable for the identification of zoophilic dermatophytes provided fresh cultures are used and the reference library was previously extended with spectra of laboratory-relevant species. Performing independent molecular methods, such as sequencing, is strongly recommended to substantiate the findings from morphologic and MALDI-TOF MS analyses, especially for uncommon causative agents.

Pour déterminer les caractéristiques épidémiologiques des dermatophytoses chez les élèves, nous avons effectué trois enquêtes transversales entre décembre 2009 et février 2012 dans des écoles primaires publiques situées dans trois zones éco-climatiques différentes du Mali. Sur un échantillon aléatoire de 590 élèves (âge moyen de 9,7 ans ; 286 garçons), la prévalence clinique des dermatophytoses était de 59,2%. La teigne du cuir chevelu (39.3%) représentait la forme clinique la plus fréquente ; la prévalence des autres dermatophytoses était de 13,6% avec une prédominance de l'atteinte de la peau glabre (81,3%). Une forte prévalence (59,5%) des cas confirmés de teigne a été enregistrée dans la zone climatique soudano-guinéenne. Nous avons mis en évidence le genre masculin et la résidence dans la zone bioclimatique Soudano-guinéenne comme facteurs de risque indépendants associés à la teigne du cuir chevelu. Les espèces de dermatophytes identifiées étaient T. soudanense (41,3%), M. audouinii (36,5%), T. violaceum (3,7%), T. mentagrophytes (2,1%) et l'association de T. soudanense avec M. audouinii (14,8%) ou T. mentagrophytes (1,6%). Sur 41 instruments de coiffure prélevés, 73,2%, étaient contaminés par deux espèces anthropophiles : T. soudanense (53,3%) et M. audouinii (46,7%). Au plan thérapeutique, nous avons évalué l'activité de la squalamine, contre des dermatophytes in vitro. Cette molécule a présenté des CMIs variant de 4 à 16 mg/l. Nous avons ensuite montré une bonne tolérance et une efficacité partielle de la squalamine en topique dans le traitement de la teigne du cuir chevelu dans un essai clinique de phase II, randomisé, en double aveugle, contrôlé par placebo. / To determine the epidemiological characteristics of dermatophytoses in Malian schoolchildren, we conducted three cross-sectional surveys between December 2009 and February 2012 in three public primary schools located in three climatic zones. A randomly selected sample of 590 schoolchildren (mean age: 9.7 years, 286 males) participated in this study. Overall, three hundred and twelve participants were diagnosed to have dermatophytosis lesions, giving a 52.9 % prevalence of clinical dermatophytoses. Tinea capitis was the most common clinical presentation, with a 39.3% prevalence, whereas the prevalence other dermatophytoses was 13.6%. A high (59.5%) prevalence rate of confirmed cases of tinea capitis was observed in the Sudano-Guinean climatic zone. Male gender and living in this climatic zone were independent risks factors associated with tinea capitis. Mycological culture found T. soudanense (41.3%), M. audouinii (36.5%), T. violaceum (3.7%), T. mentagrophytes (2.1%), and the combination of T. soudanense with M. audouinii (14.8%) or T. mentagrophytes (1.6%). In addition, we found a high contamination rate (73.2%), with two anthropophilic dermatophytes: T. soudanense (53.3%) and M. audouinii (46.7%), of hairdressing tools in peri-urban area of Bamako. Regarding anti-dermatophyte therapy, we showed a significant in vitro activity of squalamine against clinical dermatophyte isolates, with MICs ranging from 4 to 16 mg/l. In a phase II, randomized, double-blind, placebo-controlled, clinical trial, a topical treatment with squalamine ointment was well tolerated and exhibited a partial clinical activity in the treatment of tinea capitis.