Fig. 1
Three-month-old Mycobacterium ulcerans colonies growing on Middlebrook 7H10 agar supplemented with 10% oleic acid, albumin, dextrose, and catalase (OADC). Scale bar = 1 mm.
Fig. 2
Five-month-old Mycobacterium ulcerans colonies growing on Middlebrook 7H10 agar supplemented with 10% OADC. Scale bar = 1 mm.
Macroscopic examination reveals the presence of large and small Mycobacterium ulcerans colonies after 3 (Fig. 1) and 5 months (Fig. 2) of growth at 30°C on Middlebrook 7H10 agar supplemented with 10% oleic acid, albumin, dextrose, and catalase (OADC). The buff-colored M. ulcerans colonies on supplemented Middlebrook 7H10 medium appear dry, waxy, wrinkled, and rough with irregular edges. Buff-colored colonies qualitatively indicate absence of mycolactone toxin production.Colonies of M. ulcerans on OADC-supplemented Middlebrook 7H10 agar are variable in size and have elevated, condensed centers which gradually flatten toward the irregular, undulating periphery (Fig. 1 and 2). Compared to the younger M. ulcerans colonies in Fig. 1, the mature M. ulcerans colonies are slightly larger and raised, exhibiting more compacted, dense colony growth (Fig. 2).
Prior to imaging, cultures were inoculated onto Middlebrook 7H10 agar supplemented with 10% OADC from frozen stock cultures stored at -70°C. Plates were wrapped with parafilm and incubated at 30°C for 3 or 5 months. Images for Fig. 1 and 2 were taken on a Fisher Scientific Stereomaster zoom microscope equipped with a 1.3 megapixel color digital camera head for direct real-time viewing via a computer monitor.
