Mycetoma: reviewing a neglected disease

Abstract

Mycetoma caused by either filamentous fungi (eumycotic) or bacteria (actinomycotic) has recently been recognized by the World Health Organization as a neglected tropical disease. Although mycetoma is preventable and treatable, especially in the early stages, it carries high morbidity and a huge socioeconomic burden. Skin and subcutaneous tissue is affected, with a classic presentation of hard woody swellings, discharging sinuses and presence of grains (containing the causative organism). Variants with swelling without sinuses have also been described. Left untreated it may involve underlying bone and muscle, leading to permanent disability. Common actinomycotic species include Streptomyces somaliensis, Actinomadura madurae, Actinomadura pelletieri, Nocardia brasiliensis and Nocardia asteroides, while Madurella mycetomatis, Madurella grisea, Pseudoallescheria boydii and Leptosphaeria senegalensis are common eumycotic agents. Men are more commonly affected than women, and the leg is the most frequently affected site. Diagnosis in suspected lesions is made with the help of grain examination, microscopy, imaging (radiography, ultrasonography, magnetic resonance imaging) and culture, and more recently by molecular methods such as PCR and molecular sequencing. Molecular sequencing for both fungi and bacteria is important for rapid and correct diagnosis, especially in culture-negative cases. Treatment is long, more successful in actinomycetoma than eumycetoma, and may require a holistic approach comprising antimicrobials, surgery and rehabilitation. Mycetoma can be prevented by simple measures such as wearing protective garments and shoes, especially in rural areas and during outdoor activities.