coagulase test

The coagulase test is an important test for identifying the pathogenicity of staphylococci. Pathogenic staphylococci can produce two coagulating enzymes, one is a coagulation factor that binds to the cell wall, and is called a coagulase, which acts directly on fibrinogen in the plasma, causing precipitation to occur, surrounding the bacteria and agglomerating into pieces. The positive result of the slide method is caused by this aggregation factor; the other coagulase is secreted outside the bacteria, called free coagulase, which turns prothrombin into a thrombin product and turns fibrinogen into Fibrin, which causes plasma to coagulate. The test tube method allows simultaneous determination of both bound and free coagulase. Basic Information Specialist classification: Infectious disease inspection and classification: pathogenic microorganism inspection Applicable gender: whether men and women apply fasting: not fasting Tips: Plasma must be fresh. Normal value The type and proportion of the flora in the body are normal, and the human body is in a dynamic balance. Clinical significance This test is only used for the identification of pathogenic grape balls. Abnormal result 1. Invasive diseases mainly cause suppurative inflammation. Staphylococcus can invade the body through a variety of routes, resulting in multiple infections of the skin or organs, and even sepsis. (1) skin soft tissue infections are mainly sputum, pain, folliculitis, purulent acne, paronychia, stye, cellulitis, wound suppuration and so on. (2) Infection of internal organs such as pneumonia, empyema, otitis media, meningitis, pericarditis, endocarditis, etc., mainly caused by Staphylococcus aureus. (3) Systemic infections such as sepsis, sepsis, etc., are caused by Staphylococcus aureus, and Staphylococcus epidermidis can cause severe sepsis when the newborn or body defense may be seriously damaged. 2. Toxic diseases caused by exotoxin produced by Staphylococcus aureus (1) Food poisoning Symptoms such as nausea, vomiting, abdominal pain, and diarrhea can occur after 1 to 6 hours of eating enterotoxin-containing food. Most patients recover within a few hours to one day. (2) scalded skin syndrome is more common in neonates, young children and adults with low immune function. It begins to have erythema, and there is skin wrinkling in 1 to 2 days, which then forms blisters and falls off the epidermis. Caused by epidermal solubilized toxins. (3) Toxic shock syndrome is caused by TSST1, mainly characterized by high fever, hypotension, erythema rash with desquamation and shock, etc. More than half of the patients have vomiting, diarrhea, myalgia, conjunctival and mucosal congestion, liver and kidney dysfunction, etc. Occasionally there is a manifestation of heart involvement. (4) pseudomembrane enteritis is essentially a dysbacteriosis enteritis, the pathological feature is that the intestinal mucosa is covered by a layer of inflammatory pseudomembrane composed of inflammatory exudate, intestinal mucosal necrosis and bacteria. About 10 to 15% of the population has a small amount of Staphylococcus aureus living in the intestine. When dominant bacteria such as Bacteroides fragilis and Escherichia coli are inhibited or killed by the application of antibacterial drugs, the resistant Staphylococcus aureus takes the opportunity. Reproduction produces toxins, causing clinical symptoms characterized by diarrhea. The people in need of examination have some of the above clinical symptoms. Positive results may be diseases: sepsis, sputum considerations Note: 1 slide method is a screening test, both positive and negative need to be tested by test tube method. 2 plasma must be fresh. 3 Heparin should be used instead of citrate as anticoagulant anticoagulated plasma. 4 This test can also be measured using a commercially available latex agglutination test kit. Inappropriate crowd: No. Forbidden before examination: Pay attention to normal eating habits and pay attention to personal hygiene. Requirements for inspection: Actively cooperate with the doctor. Inspection process Coagulase test method: 1. Slide method: add 1 drop of normal saline in the center of a clean glass slide, mix the culture to be tested with the inoculation loop (mix positive and negative control) to make a bacterial suspension, if there is no self within 10~20s When the clotting phenomenon occurs, the human or rabbit fresh plasma 1 ring is added and mixed with the bacterial suspension to observe the result. 2. Test tube method: Add 0.5 ml of rabbit or human plasma diluted 1:4 in the test tube, add 1~2 colonies of the test bacteria, set the water bath at 37 ° C, and observe the result once every 30 minutes. result: 1. Slide method: Agglutination is positive within 5~10s. 2. Test tube method: If there is a clot or a whole tube agglutination, it is positive. After 2 hours, the above phenomenon did not occur, and then left to stand for observation. Not suitable for the crowd No. Adverse reactions and risks no.