Harr Microbiology Practice Test 2025 – Your Comprehensive All-in-One Guide to Exam Success!

The test that rapidly differentiates Micrococcus from Staphylococcus is the modified oxidase test. Micrococcus species are positive for oxidase activity, demonstrating the presence of cytochrome c oxidase, which is involved in their respiratory processes. This means they can oxidize certain substrates and produce color changes indicative of this activity. In contrast, Staphylococcus species are usually oxidase-negative, reflecting their different metabolic pathways.

The modified oxidase test is specifically designed to highlight this difference in oxidase activity, making it a rapid and effective tool for differentiating between these two genera of bacteria. This is particularly useful in clinical microbiology for accurate identification and subsequent treatment decisions based on the type of bacteria present.