Appropriate diagnosis and treatment of eumycetoma may vary significantly depending on the causative agent. To date, the most common fungus causing mycetoma worldwide is Madurella mycetomatis. This species fails to express any recognizable morphological characteristics, and reliable identification can therefore only be achieved with the application of molecular techniques. Recombinase polymerase amplification (RPA) and loop-mediated isothermal amplification (LAMP) are proposed as alternatives to phenotypic methods. Species-specific primers were developed to target the ribosomal DNA (rDNA) internal transcribed spacer (ITS) region of M. mycetomatis. Both isothermal amplification techniques showed high specificity and sufficient sensitivity to amplify fungal DNA and proved to be appropriate for detection of M. mycetomatis. Diagnostic performance of the techniques was assessed in comparison to conventional PCR using biopsy specimens from eumycetoma patients. RPA is reliable and easy to operate and has the potential to be implemented in areas where mycetoma is endemic. The techniques may be expanded to detect fungal DNA from environmental samples.
Madurella mycetomatis is the most common causative agent of human eumycetoma worldwide, as evidenced in a recent review and meta-analysis on the disease (1). This highly morbid and destructive infection mainly affects individuals of low socioeconomic status in arid climate zones in the tropics (2). Although mycetoma was introduced into the medical literature in the 18th century, it still remains neglected and it has recently been recognized by the World Health Organization as a neglected tropical condition (2-4). The prevalence of the infection in villages in Sudan where the condition is endemic is estimated to be 14 per 1,000 inhabitants (5). At the Mycetoma Research Centre, Khartoum, Sudan, the main reference center in the country, the annual incidence of new cases is Ͼ300 (6). Despite this high incidence, appropriate diagnoses and therapies for this disease are still lacking (7).Mycetoma is a subcutaneous infection that mainly affects the extremities and leads to massive disfigurement and disability (8, 9). The infection is thought to occur as a result of transcutaneous trauma, which allows insertion of the causative agent into skin and subcutaneous tissue. A distinctive and unique feature of mycetoma agents is their ability to form compact grains in infected tissue that will be discharged through the sinuses (10). Since mycetoma can be caused by both bacteria (actinomycetoma) and fungi (eumycetoma), the discharged grains are different (11). Black grains are caused by fungi, while actinomycetoma grains are white, yellow, or red (2, 10, 12). Molecular phylogeny of the eumycetoma causative agents has shown that the black-grain agents belong to entirely different fungal species, and these fungi differ in their antifungal susceptibility profiles (13,14). Therefore, precise identification of the causative agent is necessary.Current techniques for mycetoma diagnostics mostly co...