Staph Bacteria

What is Staph bacteria ?

        Staphylococcus aureus is, like all staphylococci, a Gram-positive shell with a diameter of about 1 micrometer in clusters appearing in the microscopic examination.
It is still not sporulated and has no visible capsule microscope.

Characteristics of Staph bacteria culture

        It grows easily on ordinary media aerobic as anaerobic training on solid media, colonies of smooth, shiny and curved, more or less pigment in yellow gold hence the name Staphylococcus aureus Staphylococcus or "golden". In liquid medium, it produces in the broth, a homogeneous disorder.
It has no requirements. If the ideal conditions for growth are a temperature of 37 ° C and a pH of 7.5, major changes are allowed. Like all Micrococacceae, it multiplies in environments containing a high concentration of NaCl (5 to 10 g per cent).
It can convert many substrates, including sugars, which has little practical value except for mannitol (a polyol) and St. aureus can ferment unlike most SNA.

Enzymatic equipment of Staph bacteria

        In addition to those required for metabolic functions described above, various enzymes can be demonstrated in Staphylococcus aureus: catalase which exists in all Micrococacceae, coagulase , phosphatase, hyaluronidase, fibrinolysine, lipase and characteristic proteolysines Stahp aureus.
The presence of a coagulase identifies, in practice this case aureus. There is a free coagulase and coagulase bound. The coagulase-free is a diffusible protein, reacts as prothrombin coagulant and, within hours, plasma citrated human or rabbit. The bound, or clumping factor reacts directly with fibrinogen, causing agglutination of staphylococci when mixed with a plasma.
The activity of these enzymes explains in part the pathophysiology of staph infection, their research is also useful for the classification and typing of strains.

For a bacterium colonizes tissue, it must first adhere it. This step is crucial in the further development of the infection. staphylococcus aureus colonizes the skin and mucous membranes adhering to cells and components of the extra-cellular matrix. Colonization occurs without any prior injury. However, it is favored by any breaking of the barrier Mucocutaneous.

        Several staphylococcal constituents involved in this phenomenon. staphylococcus aureus has a large number of proteins exposed on the surface of the bacteria and have the ability to bind to molecules of the host. There is talk of adhesins. A number of these adhesins belong to the family of MSCRAMM (Microbial Surface Component Recognizing Adhesive Matrix Molecules) ie they recognize the molecules in the extra-cellular matrix. The extra-cellular matrix is composed of molecules interacting with each other and with surrounding cells. It is composed of collagen, elastin, and proteoglycans of structural glycoproteins such as fibronectin. staphylococcus aureus produces several toxins which target cell membranes. These toxins bind to target cells and cause the formation of membrane channels allowing ions (pore-forming toxins).