Koaguloidas

Koaguloidas, or coagulase, is an extracellular enzyme produced by certain bacteria, most notably Staphylococcus aureus. It catalyzes the transformation of soluble fibrinogen in blood plasma into insoluble fibrin, causing clot formation. This clotting can create a protective fibrin barrier around bacterial colonies, aiding immune evasion and tissue invasion.

There are two main forms of coagulase activity. Bound coagulase is attached to the bacterial cell wall and is often referred to as clumping factor because it can cause visible clumping of cells in plasma. Free coagulase is secreted into the surrounding environment and forms a complex with the host’s prothrombin to generate staphylothrombin, which directly converts fibrinogen to fibrin. Together, these activities promote clot formation and lesion development.

In clinical microbiology, coagulase testing helps distinguish Staphylococcus aureus from other staphylococci. S. aureus is typically coagulase-positive, whereas most other Staphylococcus species are coagulase-negative. Some species may show variable results, and additional tests are often used for accurate identification. The presence of coagulase is associated with higher virulence in S. aureus strains, contributing to abscess formation and persistent infections, while coagulase-negative staphylococci are generally less virulent but can cause device-related infections.

Laboratory methods include the slide (clumping factor) test to detect bound coagulase and the tube (free coagulase) test to detect secreted enzyme activity, often using rabbit plasma. Proper interpretation requires consideration of control strains and clinical context.