Úlcera de Buruli / Buruli ulcer

A úlcera de Buruli, uma doença infecciosa causada pela Mycobacterium ulcerans (M. ulcerans),é a terceira micobacteriose em ocorrência, após a hanseníase e a tuberculose. Essa micobacteriose atípica tem sido relatada em mais de 30 países, principalmente, nos que têm climas tropicais e subtropicais, mas a sua epidemiologia permanece obscura. Recentemente, os primeiros casos autóctones do Brasil foram relatados, fazendo com que dermatologistas brasileiros estejam atentos a esse diagnóstico. O quadro clínico varia: nódulos, áreas de edema, placas, mas a manifestação mais típica é uma grande úlcera, que ocorre, em geral, nas pernas ou nos braços. Apesar do amplo conhecimento quanto ao seu quadro clínico em países endêmicos, nas outras áreas, esse diagnóstico pode passar despercebido. Assim, médicos devem ser orientados quanto à úlcera de Buruli, pois o diagnóstico precoce, o tratamento específico e a introdução de cuidados na prevenção de incapacidades são essenciais para uma boa evolução.

Buruli ulcer, an infectious disease caused by Mycobacterium ulcerans, is the third most prevalent mycobacteriosis, after tuberculosis and leprosy. This atypical mycobacteriosis has been reported in over 30 countries, mainly those with tropical and subtropical climates, but its epidemiology remains unclear. The first autochthonous cases of infection in Brazil have recently been described, making this diagnosis important for Brazilian dermatologists. Clinical manifestations vary from nodules, areas of edema, and plaques, but the most typical presentation is a large ulcer, usually in the limbs. Despite considerable knowledge about its clinical manifestations in some endemic countries, in other areas the diagnosis may be overlooked. Therefore, physicians should be educated about Buruli ulcer, since early diagnosis and treatment, including measures to prevent disability, are essential for a good outcome.

[Rate of production of inflammatory cytokines TNF and IL- by peripheral blood mononuclear cells stimulated with mycolactone]

Mycobacterium ulcerans is the etiological agent of Buruli ulcer [BU]; the third most common mycobacterial infection in humans after tuberculosis and leprosy. BU is now considered by the WHO to be an emerging infection of major concern. M. ulcerans produces mycolactone toxin, which is required for the organism's virulence. Mycolactone destroys tissue and suppresses host immune responses. In this descriptive analytical study, peripheral blood mononuclear cells from three volunteers with no history of buruli ulcer were used. IL-6 and TNF produced by these cells at different preincubation times with LPS and mycolactone were measured by using ELISA kits. This study showed hyper inhibition of IL-6 and TNF production by mycolactone. TNF levels in the control tubes [containing LPS] in 4hours reached its maximum value and then decreased. While the production of IL-6 in the tube with fresh cells [zero time] had the highest value, after 16hours, it reached its minimum. Since TNF and IL-6 are important immunity inflammatory cytokines, it can be well imagined that decrease of TNF production by this bacterium plays a role in weakening of inflammatory response. So Mycobacterium ulcerans destroys macrophages and at the same time prevents TNF production by important cells in innate immune mechanism