morphology and dyeing
mening membrane inflammation is a gram-staining negative, often double-arrangement, a doubles having a diameter of about 0.8 μm . Single bacteria is kidney shaped. When double arrangement, the two concave faces are opposite. No spur, no split is formed. Macaremia, newly separated strain has capsular.
Specific oxygen. High nutritional requirements. The most common medium is chocolate culture medium. The blood agar medium made of blood was heated 80 ° C. When the culture is initially separated, 5% to 10% of CO2 gas is also required. After 48 hours in culture, the meningum is formed in a circular ridge on the medium, and the surface is gloss, transparent or translucent dew drops of 1 mm to 5 mm in diameter. Colorless formation. No hemolytic phenomenon on the blood plane.
Decomposing the sugar-produced acid is not yet gas. Oxidase test positive. Menmachi can produce self-dissolving enzymes, if it is not timely transgenerated, the bacteria is obeyed after several days.
antigen construction and classification
1. Capsular Polysaccharides antigen has group specificity. According to this antigenicity, the meningum is divided into at least 13 serum groups. The relationship with human disease is mainly A, B, C, Y and W-135 groups. The A group and C groups are the major serum groups that cause epithelial inflammation.
2. Outer MEMBRANE PROTEIN has a type specificity. Based on the outer membrane protein to divide meningitis nursa into 20 blood types. Type 2 and 15 types related to epidemic cerebrospinal meeding. The function of the outer membrane protein is to form a pore on the bacterial cell wall, which is advantageous for nutrients into the cell.
3. Lipopolysaccharal antillars (LPS) This antigen has a common antigen with E. coli. Lipopolysaccharides are the main pathogenic substances of meningum in Nursa.
The resistance of meningitis is weak to the external environment. Dry, sunshine, wet heat and general disinfectant quickly kill bacteria. The bacteria can produce a self-soluble enzyme. In vitro 25 ° C, the alkaline environment will soon cause the bacteria swelling, cracking death.
Pathogenicity and immunity
1. Vulnese: capsules can resist the phagocytosis of phagocytic cells in the host, enhance bacteria to the body's invasion.
2. Phane: Medium bacteria mediates the surface of the host susceptible cells, which is advantageous to settle in the host, reproduction.
3. Endotoxin: It is the main pathogenic substance of meninga Naztea. The endotoxin acts on small blood vessels or capillaries, causing blood suppression, bleeding, and manifesting the skin hemorrhagic ecmissal; acting on adrenal gland, leading to adrenal bleeding. A large number of endotoxins can cause diffuse intravascular coagulation, DICs, resulting in shock and poor prognosis.
epidemic cerebrospinal membrane (abbreviated brain) is a suppurative meningitis caused by meninga Naztea (NM) through respiratory tract.
Human is the only susceptible host of Mennean Naztea. Bacteria intrusion into the body by the nasopharyngeal portion, relies on the effect of bacteria adhesion to the surface of the nasopharyngeal mucosa epithelial cells. Most people are infected with a state or a recessive infection, and the bacteria is only removed after a short stay in the body. Only a few people develop into meningitis. my country has caused meningitis, and B groups are often a state of bacteria. The pathogenesis of meningum inflammatory infection can be divided into three stages:
1 pathogens first invaded by nasopharyngeal, relied in the surface of the nasopharyngeal mucosa epithelial cell surface, causing local infection; / p>
2 subsequent bacteria invade blood flow, causing symptoms such as fungalmia, accompanying cold, fever, vomiting, skin hemorrhagic splash, etc. The blood and lymph solution reacly reaches the brain spinal cord, causing cerebrospinal cyprotary inflammation. Patients have high heat, headache, injection vomiting, and neck-tone-backed mening membrane stimulus. Severe people can lead to DIC, circulatory system failure, and enter coma within hours after the onset. The pathological changes are expressed as mening membrane acute suppurative inflammation accompanied by vascular embolism and white blood cells.
Immunogeneous immunity is mainly immunized by body fluid immunity. Anti-infection, recessive infection or vaccination for 2 weeks, the level of serum in serum is significantly increased. Secrecy IgA antibody prevents meningum in Naztea invaded respiratory mucosal epithelial cells; serum IgG and IgM antibody have the effect of killing pathogens under the participation of complements; serum antibodies can enhance phagocytic bacteria to cause phagocytes to pathogenesis under complement Kill. Infants within 6 months can obtain IgG antibodies through the parent, which produces natural passive immunization, so infection is rare. After 6 months, the level of antibody from the mother gradually decreased, and the susceptibility of the infant gradually increased, so the child's immunity was the lowest in infants, and it was a vulnerable population of meningiane.
Take the patient's cerebrospinal fluid or pungent skin bleeding and sputum to remove exudate. The blood specimens were cultured. Macaretic assault detection can take nasopharyngeal swabs.
Direct smear detection
The cerebrospinal fluid is centrifuged, and the deposition smear is taken, and the Gram-stained post-mirror test. Or disinfected patients with skin bleeding, use a sterile needle to pick out the osmium to remove the oozade, the Gram-stained post-lens test. In the mirror, a preliminary diagnosis can be made when there is a gram-staminated binococcus, which has a Gram-dyed negative dualococcus.
Isolated culture and identification
The blood and cerebrospinal fluid specimens were placed on the serum broth culture medium, inoculated onto chocolate, placed on a chocolate, placed in 5% to 10% Incubation in the CO2 environment. Picking suspicious colonies and smear detection, and biochemical reactions (Table 13-1) and agglutination test identification of type specific multivalent serum.
is mainly carried out by oxidase, sugar fermentation, and cultural growth characteristics.
1 Bacterial morphology is kidney shaped;
2 oxidase test positive;
3 tonar enzyme test positive;
4 decomposing glucose The maltose is not yet gas;
5 capsular polysaccharide antigen direct agglutination test.
Depending on capsular polysaccharide, meningin Nazhi can be divided into A, B, C, D, X, Y, Z, 29E, W135, L , 13 serum groups such as H, I, and K, where A, B, and C are most common, accounting for 90%.
About the diagnosis of serum agglutination method, it is recommended that the meningum Nariobacterium produced by Tianjin Bioconch Chip Company has a full set of serum products. This product has a diagnosis of serum in 10 common serum groups containing meningin Nazhimonium.
Nucleic acid amplification method
The clinical diagnosis of epidemic meshitis is usually based on the clinical symptoms such as fever, vomiting, and headache. Further confirmed diagnosis needs to be separated from the patient's cerebrospinal fluid or acute flavor. However, the detection positive rate of the separation culture method is low. And at least 2 to 3 d can be diagnosed infection. This is very disadvantageous for the timely treatment of the disease. In addition, affected by antibiotics and other non-specific factors. The sensitivity of the separation culture method is not high. It greatly reduces the reliability of diagnostic results. Therefore, finding a fast, sensitive and detection method for i clinical diagnosis is very prosperous. In recent years, because of the advantages of good specificity, high sensitivity and short detection cycle, gene diagnostic techniques established on the basis of PCR have been widely used in clinical detection of various pathogenic microorganisms. The Huaxi Public Health School of Sichuan University is jointly established by the PCR technology based on PCR technology, and established a rapid diagnosis method of NM ABC groups.
Nucleic acid amplification technology, Polymerase Chainrection, PCR, the basic principle is designed, synthesized two oligonucleotides, as primers, corresponding to a pathogen to be tested At both ends of the specific sequence, then the process of replication in vitro simulation DNA in vivo is repeatedly amplified, and the target sequence is larger or even millions of tens of thousands of times.
Rapid Diagnosis method
Based on the soluble antigen in cerebrospinal fluid and serum in patients with meningitis. Therefore, there is a known antibody to detect a corresponding antigen.
1. Convective immune electrophoresis: This method is more sensitive to conventional cultures and high specificity. It can generally be obtained within 1 hour.
2. SPA Collaborative Test: Mix the patient's brain or serum to be tested with a mixed glutinous glutinus that produces spa in Naztea IgG antibody. If there is a soluble antigen in Neather bacteria in the specimen, the antibody labeled aureus is gathered together to form the agglutination of the naked eye.
Prevention and control principles
Preventing the key infection of meningum infection infection is to eliminate infectious sources as soon as possible, cut off the transmission pathway and improve the immunity of people.
my country officially uses A group of multi-gangfu seedlings in 1980, and clinical observations suggests that school-age children and adult protection rates can reach 90%. However, this vaccine is poorly immunized by infants under the age of 2. One is because the meningitis capsular polysaccharide antigen belongs to T cells non-dependent antigen, and the immune effect is obviously dependent on the age of the vaccination; its second, polysaccharints induced The IgG antibodies produced by the body are mainly IgG2 subclasses, and there is late, usually from 8 to 12 years old to rise to adult levels. Therefore, after the infant mixed polysaccaine is often mainly based on a short IGM antibody. Foreign A group and C groups were used to inoculate 8 to 10 weeks old infants with a population of 3 to 10 weeks of age, which proves that this conjugated bacteria has good immunogenicity and safety.
The treatment of the treatment of the brain is penicillin G, and the dose is large. Chloramphenicol or erythromycin can be used to allergies with penicillin.