VNTR confirms the heterogeneity of Madurella mycetomatis and is a promising typing tool for this mycetoma causing agent

The neglected tropical disease mycetoma is a chronic granulomatous inflammatory and infectious disease affecting various body parts. The most common causative agent is the fungus Madurella mycetomatis. In order to study the genetic diversity of this fungus and to monitor any potential outbreaks, a good typing method that can be used in endemic settings is needed. Previous typing methods developed were not discriminative and not easy to perform in resource-limited laboratories. Variable-Number-Tandem-Repeat (VNTR) typing overcomes these difficulties and further enables interlaboratory data comparison. Therefore, in this study we developed a VNTR method for typing M. mycetomatis. Six tandem-repeats were identified in the genome of M. mycetomatis isolate MM55 using an online tandem repeats software. The variation in these repeats was determined by PCR and gel-electrophoresis on DNA obtained from 81 M. mycetomatis isolates obtained from patients. These patients originated from Sudan, Mali, Peru, and India. The 81 isolates were divided into 14 genotypes which separated into two main clusters with seven and five subdivisions, respectively. VNTR typing confirms the heterogeneity of M. mycetomatis strains and can be used to study the epidemiology of M. mycetomatis. The results presented in this article are made fully available to the scientific community on request from the Eumycetoma Working Group. We hope that this open resource approach will bridge scientific community working with mycetoma from all around the world and lead to a deeper understanding of M. mycetomatis.