They are rods, coccal rods, or cocci, sized at about 0.5-1.0 x 0.5-2.6 μm. They are obligately aerobic, but some can undergo anaerobic respiration if nitrate is present. They tend to be colorless. They typically occur in the soil and water, and some live in the intestinal tracts of vertebrates. Samples from blood, urine, feces, discharge from ears, spinal fluid, and wounds have produced this type of bacteria. Zoonotic infections from ferrets have been recorded.[4]