In which group of bacteria would you find oxidase-negative species?

The Enterobacteriaceae family includes a wide variety of bacteria, many of which are commonly found in the intestinal tract of humans and animals. This family is characterized by being oxidase-negative, meaning they do not produce the enzyme cytochrome oxidase, which is involved in the electron transport chain for energy production. This trait is a key biochemical characteristic that aids in identifying members of this family during laboratory testing.

In contrast, other groups of bacteria might include oxidase-positive species. For instance, while Vibrionaceae contains certain species that are oxidase-positive, Micrococcaceae generally has members that are also oxidase-positive. Streptococcaceae, though primarily known for being catalase-negative, can exhibit varied oxidase reactions, making it less definitive in this context. Therefore, the identification of Enterobacteriaceae as a group of predominantly oxidase-negative species is grounded in fundamental microbiological principles and biochemical testing practices.