A point mutation in the napA gene may cause the negative characteristic of nitrate reduction in Mediaevalis and Microus strains. A 122-bp frameshift deletion in the araC gene may lead to the arabinose negative phenotype of Microus strains.

• 所有脱氮阴性菌株的napA基因发生了突变 ,所有甘油利用阴性菌株的 glpD基因发生了突变 ,所有阿拉伯糖利用阴性菌株的araC基因发生了突变。