Which of the following characteristics is true for the Enterobacteriaceae family?

The Enterobacteriaceae family, which includes many important genera such as Escherichia, Klebsiella, and Salmonella, is characterized by several distinctive biochemical properties. The correct choice highlights that members of this family ferment glucose, reduce nitrate to nitrite, and are oxidase negative.

Fermenting glucose is a fundamental characteristic of Enterobacteriaceae, allowing them to utilize glucose as a primary source of energy through fermentation pathways. The reduction of nitrate to nitrite is another common trait within this group, as many Enterobacteriaceae possess nitrate reductase enzymes that facilitate this process, which can be used to differentiate them in laboratory settings.

Additionally, being oxidase negative distinguishes the Enterobacteriaceae from other enteric pathogens, such as Pseudomonas, which are oxidase positive. This oxidase test is a useful diagnostic tool in microbiology.

In contrast, while some members of the Enterobacteriaceae family do produce gas during fermentation, the other options incorporate characteristics that do not universally apply to all members of this family or contain inaccuracies, making them less applicable as defining traits. Hence, the combination of glucose fermentation, nitrate reduction to nitrite, and oxidase negativity reflects the characteristics that are true for the Enterobacter