Which of the following is a common laboratory test for identifying Staphylococcus aureus?

The coagulase test is a common laboratory method used to identify Staphylococcus aureus, a key pathogen responsible for various infections. This test detects the presence of coagulase, an enzyme produced by Staphylococcus aureus that causes blood plasma to coagulate. Positive coagulase test results are indicative of S. aureus, as other Staphylococcus species are typically coagulase-negative and do not produce this enzyme.

Blood cultures, while valuable for identifying bacteria in the bloodstream, are not specific for distinguishing Staphylococcus aureus from other organisms. Gram staining, although useful for determining the presence and general classification of bacteria, does not differentiate between Staphylococcus species on its own. PCR analysis can be employed to detect specific genetic material from Staphylococcus aureus, but it is not as commonly used for routine identification in a basic laboratory setting compared to the coagulase test. Thus, the coagulase test remains a mainstay in the identification of this particular bacterium in a clinical environment.