Molecular detection of M. mycetomatis in soils and thorn samples. (A) Results of the broad-spectrum ITS PCR employing primers ITS4 and ITS5. Note that amplicons can be observed in all lanes. (B) Result of the nested PCR using M. mycetomatis-specific primers. Lanes 1 to 6, amplicons derived from Dutch control samples: lanes 7 to 14, amplified material from Sudanese samples; lane 15, results obtained with purified M. mycetomatis DNA; lanes 16 and 17, negative controls; lanes M, 100-bp molecule sizing ladder, and the 600-bp fragment is indicated (arrow).