Which test differentiates Staphylococcus aureus from Staphylococcus intermedius?

The ability to differentiate Staphylococcus aureus from Staphylococcus intermedius is crucial in clinical microbiology, particularly due to their differing pathogenic potential. The slide coagulase test is a reliable method for this differentiation, as Staphylococcus aureus produces coagulase, an enzyme that causes blood plasma to clot. This test involves mixing a bacterial colony with plasma on a slide; if the coagulase is produced, visible clumping occurs, indicating Staphylococcus aureus.

While Staphylococcus intermedius does not produce coagulase, it is not typically used in the slide coagulase test scenario. The other tests listed do not provide the necessary specificity for distinguishing between these two species effectively. The acetoin test relates to the ability to produce butanediol fermentation, which is unrelated to the identification of these staphylococci. The catalase test, while useful for differentiating staphylococci from streptococci (since staphylococci are catalase-positive), does not differentiate between Staphylococcus species. The urease test detects urease production, which is more characteristic of other bacterial genera and not specific for these Staphylococcus species.

The slide coagulase test stands out as the most