Enterobacteriaceae family traits: Which core biochemical properties are typically exhibited by members of Enterobacteriaceae?

Introduction / Context:Enterobacteriaceae are a large family of Gram-negative rods that inhabit the intestinal tract and environment. Rapid screening in the laboratory often relies on a combination of simple biochemical reactions that, together, define the family and help separate it from other Gram-negative groups.

Given Data / Assumptions:

• We are considering family-level properties rather than species-level exceptions.
• Tests include catalase, oxidase, and glucose fermentation.
• Nonfastidious culture on standard media is assumed.

Concept / Approach:Most Enterobacteriaceae are catalase-positive, helping them detoxify peroxides. They are characteristically oxidase-negative, distinguishing them from oxidase-positive non-fermenters like Pseudomonas. Fermentation of glucose (with or without gas) is a hallmark; lactose fermentation varies among genera (e.g., E. coli positive; Salmonella negative). Therefore, the combination of catalase-positive, oxidase-negative, and glucose fermenters is typical of the family.

Step-by-Step Solution: Evaluate catalase: generally positive across Enterobacteriaceae. Evaluate oxidase: classically negative, separating from many non-enterics. Evaluate glucose fermentation: present in family members, though gas production varies. Select the inclusive option that all statements are true.

Verification / Alternative check:Standard identification schemes (e.g., IMViC, TSI, oxidase) rely on this triad to orient the work-up toward Enterobacteriaceae.

Why Other Options Are Wrong:

• Each single statement captures only part of the family profile.
• None of these: Contradicted by textbook biochemical patterns.

Common Pitfalls:Overgeneralizing lactose fermentation as universal; it is variable within the family and should not be used alone to define membership.

Final Answer:All of these.