What is detected in the latex agglutination test for Staphylococcus aureus?

What is detected in the latex agglutination test for Staphylococcus aureus?

• A. Protein A
• B. Clumping Factor
• C. Protein A or Clumping Factor
• D. Coagulase

Answer: (C)

The key idea is that this latex agglutination test for Staphylococcus aureus targets surface proteins specific to this bacterium, not the enzyme activity alone. It detects two components: clumping factor (bound coagulase) and Protein A. If the organism has clumping factor, it binds fibrinogen on the latex beads and causes visible clumping. If Protein A is present, it binds the Fc region of IgG on the beads, also producing agglutination. Because either factor can yield a positive result, the test is designed to detect Protein A or Clumping Factor. Coagulase itself is the enzyme used in a separate coagulase test, not the latex detection in this assay.

The key idea is that this latex agglutination test for Staphylococcus aureus targets surface proteins specific to this bacterium, not the enzyme activity alone. It detects two components: clumping factor (bound coagulase) and Protein A. If the organism has clumping factor, it binds fibrinogen on the latex beads and causes visible clumping. If Protein A is present, it binds the Fc region of IgG on the beads, also producing agglutination. Because either factor can yield a positive result, the test is designed to detect Protein A or Clumping Factor. Coagulase itself is the enzyme used in a separate coagulase test, not the latex detection in this assay.