Characteristics, culture and diagnosis of Helicobacter helicobacteria

helicobacter pylori, referred to simply as Hp. It was first discovered by Barry J. Marshall and J. Robin Warren, who won the 2005 Nobel Prize in Physiology or Medicine.
morphological features
Helicobacterium is a unpolar, whiplash, end blunt circle, spiral curved bacteria. Length 2.5 to 4.0 m, width 0.5 to 1.0 m. Gloran stain negative. There's motivation. The surface of epithetical cells in the stomach mucous membrane is often typically spiral or curved. When growing
solid
cultured base, rods or cylindrical shapes can sometimes appear except in typical forms.
electron
microscope
one end of the bacteria can extend 2 to 6 whiplashes with a slug. Whiplash is visible at both ends when splitting. Whiplash is about 1 to 1.5 times longer than bacteria. It is about 30nm thick. The top of the whiplash is sometimes visible as a sprite, an extension of the crucible. A speckular root can be seen at each whipping root extending into the inside of the cell wall at the top of the bacterio. There is still an electron density reduction area on its inside. Whiplash acts as a propeller in motion and anchors in the settlement process.
Physiology and
Molecular Biology
Characteristics
Helicobacter pyridobacteria is a micro-oxygen-demanding bacteria, environmental oxygen requirements of 5 to 8%, in the atmosphere or absolute anaerobic environment can not grow. Many solid cultures can be used as basic cultures for Helicobacter pylud (Helicobacter pylut) isolation culture, and Breitbart
agaride
is used more, but only if the appropriate amount of whole blood or fetal cattle
serum
is used as a supplement. Often to vancomycin, TMP, b sexmycin B and other components of antibacterial agents to prevent the growth of bacteria.
helicobacterium is not
most classical bio
scicide experiments commonly used to identify gut bacteria in clinical and microbial experiments. Oxidase, tentacles, urea enzymes, alkaline phosphatase, r-glutamine transpeptide enzyme, leucine peptide enzyme these seven enzyme reactions are used as the basis for the bio-chemical identification of Helicobacter pylud.
whole gene sequence of helicobacter pyridobacteria has been measured, with the urea enzyme gene having four open reading boxes: UreA, UreB, UreC, and UreD. UreA and UreB
polypeptides
equivalent to two sub-unit structures of urea enzyme structures. Helicobacter pyridobacteria is extremely rich in urea enzymes, containing about 15% of the bacterial protein, the activity is equivalent to 400 times that of Bacillus deformation. Urea enzyme catalytic urea hydrolysis forms ammonia clouds to protect bacteria from survival in high acid environments. In addition, the VacA gene and the CagA gene encode bubble toxin and cytotoxin-related proteins, respectively.
According to the expression of these two genes, helicobacter pyridobacteria strains are divided into two main types: type I. contains CagA and VacA genes and expresses two proteins, type II. does not contain the CagA gene, does not express two proteins, there are still some intermediate expression, that is, the expression of one of the toxic factors. It is now thought that type I. is more closely related to stomach disease.
culture
biopsy specimens used for culture should be placed in physiological saline, nutritious broth, or 20% glucose and immediately transferred to bacterial chamber culture. If the specimen cannot be cultured within 4 hours, it should be kept at 4 degrees Celsius, but not more than 24 hours. The only way to preserve biopsy specimens for culture over a long period of time is to place them in -70 degrees Celsius or liquid nitrogen.cultured helicobacteria in the united States includes both non-selective and selective. Commonly used non-selective cultures are cerebral palsy agar, Colombian agar, trypsin soy agar, and Wilkins-Chalgren agar. The medium needs to be added 7% to 10% of the defibrin horse blood. Sheep's blood, human blood, horse serum, chlorinated hemolyxin, starch, cholesterol or cyclodextrins can also replace horse blood. The choice of medium is to add certain antibacterial drugs to the above medium, such as vancomycin, acetic acid, dymycin B, polymycin B, and methamphetamine (TMP).
commonly used are Skirrow and Dent recipes. The former was originally used in the culture of Campylobacter and can also be used in helicobacteria culture. The latter is an improvement of the former, i.e. polyciscosin is replaced with cephalosporine, because a small number (about 5%) of Helicobacter pylore strains are sensitive to polysporine. Drnt is formulated for vancomycin (10mg/L), cephalosporine (5mg/L), TMP (5mg/L) and dythromycin B (5mg/L). It has been reported that some strains are sensitive to acid, so the antibiotic should be avoided in the medium as far as possible.
Helicobacter pyrethroid infection detection methods
Helicobacter pyrethroid infection detection methods are many, including the direct examination of bacteria, urethroid enzyme activity determination, immunology detection and polymerase chain reaction methods.
(1) Direct examination of bacteria
refers to the gastric mucous membrane (mostly gastric sinus mucous membrane) for direct smearing, dyeing, tissue slice staining and bacterial culture to detect Helicobacter pyrobacteria. Among them, gastric mucous membrane bacterial culture is the most reliable method to diagnose Helicobacter helicobacterium, which can be used as a "gold standard" to verify other diagnostic tests, and at the same time, it can carry out drug sensitivity tests to guide clinical selection of drugs.
(2) Urological enzyme examination
Because Helicobacter pyrobacteria is the only bacteria in the human stomach that can produce a large number of urinary venom enzymes, helicobacter pyrobacteria infection can be diagnosed by detecting urinary venom enzymes. Urinase breaks down the gastric urethra to produce ammonia and carbon dioxide, so that urea concentration is reduced and ammonia concentration is increased. Based on this principle, a variety of testing methods have been developed: (1) gastric biopsy tissue urine venom test; (2) respiratory test; (3) gastric urea or urea nitrogen determination; (4) 15N-urea test.
(3) Immunological Testing
There are a variety of immunological testing methods to detect Helicobacter pyrobacteria
antibodies
in the serum, including complement binding tests, coagulation tests, passive blood coagulation assays, immunoprinting techniques and enzyme-combined adsorption assays (ELISA).
(4) Polymerase chain reaction technology
Normal gastric mucous membranes rarely detect helicobacter pyrethroids (0 to 6%), chronic gastritis patients helicobacter pyrethroid detection rate is very high, about 50% to 80%, chronic active gastritis patients Helicobacter pyrethroid detection rate is higher, up to more than 90%.
(5) C-14 exhalator and exhalator detection pocket
only need to blow air for 5 minutes, no other discomfort. This method enables many patients with high blood pressure, heart disease and allergies to gastroscopy to avoid the discomfort of gastroscopy, which is one of the ideal detection methods. Is currently the detection of HP in the medical community's gold standard. Sensitivity 95%, specificity 95% to 100%.