There is now considerable evidence to suggest that this disease is an infection. Mycobacterium ulcerans has recently been isolated from lesions and is unique to tropical ulcers.[5] Early lesions may be colonized or infected by, Bacillus fusiformis (Vincent's organism), anaerobes and spirochaetes. Later, tropical ulcer may become infected with a variety of organisms, notably, staphylococci and/or streptococci.[4] The condition has been shown to be transmissible by inoculation of material from affected patients.[5]