Which test is primarily used to distinguish the Micrococcaceae family from the Streptococcaceae family?

The catalase test is crucial for differentiating members of the Micrococcaceae family from those in the Streptococcaceae family. Micrococcaceae, which includes genera like Staphylococcus and Micrococcus, are catalase-positive, meaning they produce the enzyme catalase that breaks down hydrogen peroxide into water and oxygen. This reaction produces bubbles when hydrogen peroxide is applied to a colony. In contrast, Streptococcaceae, which includes Streptococcus species, are catalase-negative and do not produce this enzyme. This key difference provides a straightforward and reliable means of classification between these two families based on the presence or absence of catalase.

While other tests like bacitracin sensitivity and hemolysis patterns can offer additional information, they are not primarily definitive for distinguishing between these two families. Therefore, the catalase test stands out as the most direct and effective method for this specific differentiation.