One of two usually recognized orders of true bacteria,gram-negative spiral or spherical or rod-shaped bacteria usually motile by polar flagella,some contain photosynthetic pigments.

• 两个公认的真细菌目之一，革兰士阴性螺旋形球形或杆形细菌，通常通过极性鞭毛移动，有的含有光合色素。