What is a key biochemical test used to differentiate Enterobacteriaceae?

The urease test is a key biochemical test used to differentiate members of the Enterobacteriaceae family, particularly to distinguish species that are urease positive from those that are urease negative. This is significant because certain Enterobacteriaceae, like Proteus spp., can hydrolyze urea to ammonia, leading to alkaline conditions and a color change in the medium, which is a characteristic feature of urease-positive organisms.

In contrast, organisms that do not produce urease will not change the pH of the medium, maintaining an acidic environment. This test can help distinguish between similar species within this family, which is important for accurate identification and appropriate treatment.

While other biochemical tests, such as the catalase test, oxidase test, and coagulase test, are useful in microbial identification, they are less specific for Enterobacteriaceae differentiation. For instance, the catalase test differentiates catalase-producing organisms from non-producing ones across many bacterial genera, the oxidase test is primarily used to distinguish between oxidase-positive and oxidase-negative bacteria (helpful for identifying specific groups like Pseudomonas but not Enterobacteriaceae), and the coagulase test is mainly used for differentiating Staphylococcus aureus from other