S. aureus uses<unk>  to form a fibrin<unk> t from fibrinogen present in the bloodstream. This helps the bacteria evade detection and phagocytosis by the immune system.<unk>  is a protein enzyme produced by several microorganisms that enables the<unk> nversion of fibrinogen to fibrin. In the laboratory, it is used to distinguish between different types of Staphylococcus isolates. Importantly, S. aureus is generally<unk> -positive, meaning that a positive<unk>  test would indicate the presence of S. aureus or any of the other 11<unk> -positive Staphylococci. A negative<unk>  test would instead show the presence of<unk> -negative organisms such as S. epidermidis or S. saprophyticus. However, it is now known that not all S. aureus are<unk> -positive. Whereas<unk> -positive Staphylococci are usually pathogenic,<unk> -negative Staphylococci are more often associated with opportunistic infection. It is also produced by Yersinia pestis.<unk>  reacts with prothrombin in the blood. The resulting<unk> mplex is called staphylothrombin, which enables the enzyme to act as a protease to<unk> nvert fibrinogen, a plasma protein produced by the liver, to fibrin. This results in clotting of the blood.<unk>  is tightly bound to the surface of the bacterium S. aureus and can<unk> t its surface with fibrin upon<unk> ntact with blood. The fibrin clot may protect the bacterium from phagocytosis and isolate it from other defenses of the host. The fibrin<unk> t can therefore make the bacteria more virulent. Bound<unk>  is part of the larger family of MSCRAMM adhesin proteins.
Coagulase
Hemostat
Fibrinolysin
Transfer factor
Thrombin
Proteases 
Streptokinase
Prothrombinase