In 20 grade 1 ulcers (92%), no virulence genes were identified whereas these genes were present in all but one grade 2-4 ulcers.

• 除了1名病人外，致病基因在所有2-4级溃疡病人中都被检测到，而在1级溃疡病人中，20名(92%25)未检测出致病基因。