Original article/Article original
Epidemiology and fungal species distribution of superficial mycoses in Northeast BrazilÉpidémiologie et distribution des espèces fongiques des mycoses superficielles dans le Nord-est du Brésil

https://doi.org/10.1016/j.mycmed.2016.08.009Get rights and content

Summary

Objective

Dermatomycoses are superficial fungal infections which affect the skin, hair and nails of humans and animals. Male and female patients of all ages are affected by this condition. The main etiological agents of dermatomycoses are the dermatophytes fungi of the genera Trichophyton, Microsporum and Epidermophyton, while the main yeasts belong to the genera Candida, Malassezia and Trichosporon. The variation in the distribution of dermatomycoses worldwide justify the conduction of epidemiological studies in order to contribute for the better understanding of patterns of mycological cutaneous infections. This study was conducted from April 2013 to December 2014.

Material and methods

A total of 205 patients were evaluated, while 235 clinical specimens were obtained. From our positive cases of mycological examination, 73 (64.6%) patients were female, while 40 (35.4%) were male. Scales from the skin and nails were collected and observed at optical microscopy after potassium hydroxide clarification. Cultures were performed on Sabouraud Dextrose Agar added chloramphenicol. Identification was performed by classic methodology.

Results

We found that the glabrous skin was the largest source of dermatomycoses (30.11%), followed by toenails (27.4%) and fingernails (17.7%). Regarding onychomycosis, the most affected population was over 50 years old. Trichophyton rubrum was the dermatophyte fungal species more commonly found. Most of the patients with pityriasis versicolor were adults and female. Another important fact observed is that Candida parapsilosis was the most prevalent species. Finally, a high incidence of T. tonsurans in cases of superficial mycoses was observed.

Conclusion

Our results clearly demonstrate peculiarities in terms of etiological agents of dermatophytoses distribution in a specific region of Brazil.

Résumé

Objectif

Les mycoses cutanées sont des infections fongiques superficielles qui affectent la peau, les cheveux et les ongles chez l’homme et les griffes des animaux. Les patients masculins et féminins de tout âge sont touchés par cette maladie. Les principaux agents étiologiques de la dermatomycose sont les dermatophytes des genres Trichophyton, Microsporum et Epidermophyton, alors que les principales levures appartiennent aux genres Candida, Malasezzia et Trichosporon. Les variations de la distribution mondiale des dermatomycoses justifient la conduction d’études épidémiologiques afin de contribuer à une meilleure compréhension des tendances des infections cutanées mycologiques. Cette étude a été réalisée entre avril 2013 et décembre 2014.

Matériel et méthodes

Un total de 221 patients ont été évalués, 255 échantillons cliniques ont été obtenus. Dans les cas d’examen mycologique positif, 87 (65,4 %) patients étaient des femmes, alors 46 (34,6 %) étaient des hommes. Les produits de grattage de la peau et des ongles ont été recueillis et observés au microscope optique après clarification par l’hydroxyde de potassium. Les cultures ont été effectuées sur gélose Sabouraud additionné de chloramphénicol. Ainsi, l’identification a été réalisée par une méthodologie classique.

Résultats

Nous avons constaté que la peau glabre était la principale source de mycoses superficielles, suivie par les ongles. En ce qui concerne l’onychomycose, la population de plus de 50 ans a été la plus touchée. Trichophyton rubrum a été l’espèce des dermatophytes plus fréquemment trouvée. La plupart des patients souffrant de pityriasis versicolor ont été des adultes et des femmes. Un autre fait important observé c’est que Candida parapsilosis était l’espèce de levure la plus répandue. Enfin, une forte incidence de T. tonsurans a été observée.

Conclusion

Nos résultats démontre clairement les particularités en termes d’agents étiologiques et de la distribution des dermatophytoses dans une région spécifique du Brésil.

Introduction

Dermatomycosis are superficial fungal infections which affect the skin, hair and nails of humans and animals. They affect both male and female patients of all ages and have a worldwide distribution. However, hot and humid climates such as in tropical and subtropical areas contribute to the high prevalence of number of cases in countries from Latin America, Africa and Asia [2], [11], [39].

Superficial fungal infections are related to several predisposing factors, including: climate conditions, people migrations, sports activities, prolonged contact with water, lifestyle, immunological status, drug therapy and age of patients [11]. In addition, life conditions and the environment where people are inserted influence epidemiological characteristics of human infection [11].

The main etiological agents of dermatomycosis are the dermatophytes fungi of the genera Trichophyton, Microsporum and Epidermophyton. The non-dermatophyte agents include other filamentous fungi such as Fusarium and Aspergillus and mainly yeasts belonging to the genera Candida, Malasezzia and Trichosporon [9].

Dermatophytes fungi are filamentous, hyaline, septate and present arthroconidia in their micromorphology. The high incidence of these fungi on epidemiological data of dermatomycosis is influenced by the high production of keratinasis, an important enzyme used for acquisition of nutrients from the environment, but also contributes for fungal invasion of the stratum corneum of epidermis and to degrade keratin of the skin, hair and nails [9]. Therefore, these fungi are known as keratinolytic [6].

Yeasts belonging to the Candida genus are also involved in superficial infections and the main species isolated from dermatomycosis are the Candida parapsilosis species complex, Candida albicans and Candida tropicalis. The lesion occurs mainly in intertriginous areas of the body, such as interdigital, inguinal, intergluteal and inframammary regions as well as nails and periungueal regions [37]. The genus Malassezia comprises lipophilic yeast-like fungi that are part of the normal skin microbiota in humans and warm-blooded animals [15].

The variation in the distribution of dermatomycoses according to the local geography, inspires the conduction of epidemiological studies in order to contribute for the better understanding of patterns of mycological dermatomycoses and etiologic distribution of the most common fungal agents which cause infection in the skin and its annexes. Of note, each species presents peculiarities in terms of body sites and age of patients which they cause disease. Therefore, this study aimed to conduct an epidemiological survey of dermatomycoses derived from patients in a private laboratory located in Northeast Brazil. This data will contribute to increase the discussion on the epidemiology of dermatomycosis in a region of Brazil where this clinical scenario is poorly investigated.

Section snippets

Collection of clinical specimens

Strains were collected from April 2013 to December 2014 at a private clinical laboratory analysis from the city of Natal, Rio Grande do Norte State, Northeast Brazil and sent for further identification at the Laboratory of Medical and Molecular Mycology, Department of Clinical and Toxicological Analysis, Federal University of Rio Grande do Norte. The patients were referred by dermatologists from different clinical ambulatories of the state. During the period of the study, 205 patients of both

Results

In the present study a total of 205 patients were evaluated, while 235 clinical specimens were obtained. A total of 225 samples were analyzed by direct microscopic examination (DME) and culture. Of note, 113 clinical specimens were positive, while 122 were negative for mycological examination. We obtained 42.7% (96 cases) correspondence between direct examination and culture (Table 1). From our positive cases of mycological examination, 73 (64.6%) patients were female, while 40 (35.4%) were

Discussion

In the present study, we observed that among positive cases of mycological examination there was a higher prevalence of female patients with dermatomycosis. It seems that differences in distribution of positive cases of superficial fungal infections between both genders are variable worldwide. For instance, in a retrospective study from 2004 to 2014 performed in China, male patients were predominant (55.3%) rather than female (44.7%) [4]. The same distribution per gender was observed in a

Disclosure of interest

The authors declare that they have no competing interest.

Acknowledgements

We are very grateful to Brazilian Ministry of Education for financial fundings. We also would like to thank Professor Arnaldo Lopes Colombo for donation of reference strains used as controls for fungal identification and to Professor Marcelo Lancellotti for the critical review of the French translation.

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