Helicobacter pylori: the main carcinogen that infects 4 billion people.

In the physical examination report, people sometimes see that the report says "Helicobacter pylori positive". Some people who are positive for Helicobacter pylori take it for granted, while others are worried and can't sleep at night. So, what exactly is Helicobacter pylori? What are the symptoms of Helicobacter pylori infection? Does helicobacter pylori positive need treatment?

There are two mouths in human stomach, the entrance is called cardia and the exit is called pylorus. The pylorus is the transitional part from the stomach to the duodenum. There is a special kind of bacteria growing here, called Helicobacter pylori.

Helicobacter pylori (HP) is a kind of Gram-negative bacteria with spiral curvature, blunt end, single-stage multi-flagella and slight aerobic capacity. Like to grow on the surface of gastric mucosal epithelial cells and the bottom of gastric mucus, the number of gastric antrum is the most, and the number of gastric body and bottom is less. It is the only microorganism known to survive in human stomach.

Helicobacter pylori is comparable to mice and cockroaches in the bacterial world, and has settled in the stomachs of more than 4 billion people around the world. The infection rate in some developing countries is as high as 80% ~ 90%. From June 2002 to June 2004, China Helicobacter pylori research cooperation group conducted an investigation in 19 provinces, municipalities and autonomous regions. The results showed that the total infection rate of Helicobacter pylori was 56.22.

The infection rate of Helicobacter pylori varies from region to region. The infection rate of Helicobacter pylori in developing countries is relatively high, but the infection rate of Helicobacter pylori in developed countries is rapidly decreasing. However, in developed countries, the infection rate of Helicobacter pylori among the first and second generation immigrants from developing countries is much higher than that of other populations. Therefore, the health department generally believes that medical and health conditions and the level of socio-economic development are the key factors for whether Helicobacter pylori can become a climate.

When it comes to the discovery of Helicobacter pylori, Robin Warren, an Australian pathologist, and Barry Marshall, a professor of clinical microbiology have to be mentioned.

During 1979, a curved bacterium was observed in the gastric antrum mucosa of Robin Warren's chronic gastritis patients, and it was found that there was always inflammation in the gastric mucosa adjacent to this bacterium. Some people suspect that this bacterium is closely related to chronic gastritis. 198 1 year, Barry Marshall cooperated with Warren to confirm this suspicion. They also found that all patients with duodenal ulcer, most patients with gastric ulcer and about half of patients with gastric cancer also had the bacteria in their gastric mucosa. 1982, they put forward the hypothesis that gastric ulcer and gastric cancer are caused by helicobacter pylori, but at first they were laughed at by other scholars and doctors. Because the previous theory believed that gastric ulcer was mainly caused by stress, irritating food and hyperacidity, no one believed that bacteria would survive in a very acidic stomach.

In order to make people pay attention to this theory, Marshall drank about 20 ml of Helicobacter pylori culture solution himself, and soon suffered from gastric ulcer, which was cured with antibiotics. The action of "testing poison with one's own body" confirmed that this bacterium is the chief culprit of gastric ulcer.

Since then, the academic research on Helicobacter pylori and its related diseases has been deepening. At present, it has been clearly concluded that Helicobacter pylori infection is related to gastritis, peptic ulcer, gastric cancer and gastric mucosa lymphoma. 1994, the International Agency for Research on Cancer (IARC) under the World Health Organization (WHO) designated Helicobacter pylori as a "class I carcinogen", and it was the first prokaryote that was proved to be carcinogenic to human beings (an organism formed by a single prokaryote, which generally has no inner membrane, a heterokaryon wrapped by a nuclear membrane, no chromosomes in the cell, and the DNA strand is not spiral, but exists in the cytoplasm in a free form. According to the report of WHO, 50% of gastric cancer is related to Helicobacter pylori, and the risk of gastric cancer of infected people is 2-3 times higher than that of non-infected people. There are also some cohort studies that estimate that the life-long risk of Helicobacter pylori infection is 3 ~ 10 times that of healthy people.

Barry Marshall and Robin Warren won the 2005 Nobel Prize in Physiology or Medicine for "discovering Helicobacter pylori and its pathogenic mechanism for peptic ulcer disease".

The host range of Helicobacter pylori is very narrow, and it is almost only found in humans and other primates. Their acid resistance and exercise ability are much stronger than other bacteria. When it enters the stomach, it adds the following "four guarantees" to itself: 1 Flagella on bacteria provide the power to pass through the mucus layer. 2. Release adhesin, which is closely attached to gastric epithelial cells to avoid being emptied by the stomach with food. 3. Secreting superoxide dismutase and catalase can resist the attack of neutrophils in human immune system. 4. Urease rich in Helicobacter pylori can hydrolyze urea to produce ammonia. Ammonia is an alkaline substance, which produces an "ammonia cloud" protective layer around bacteria, which can resist the killing effect of gastric acid.

After the helicobacter pylori mucosa settles in the gastric mucosa, it will stimulate the secretion of gastric acid, thus slowly damaging the gastric wall, resulting in a certain degree of damage to the gastric wall, thus forming a peptic ulcer.

Theoretically, the longer the infection time of Helicobacter pylori, the higher the risk of gastric cancer. The younger the infection age, the greater the possibility of developing gastric cancer in the future. Helicobacter pylori can cause chronic gastritis to exist for a long time and recur, causing more than 90% of chronic gastritis. In addition, Helicobacter pylori may also bring stubborn bad breath, which can only be completely eliminated through "mass killing". Helicobacter pylori infection has been included in the screening of early gastric cancer in China.

Because of the long incubation period of infection, it is not easy to detect, and most infected people are asymptomatic. Kerwin Chen, a professor at Southern Medical University and deputy head of the Helicobacter pylori group of the Gastroenterology Branch of the Chinese Medical Association, gave such a set of data: Helicobacter pylori infection will inevitably cause chronic active gastritis, but 70% of infected people do not show symptoms; Only 10% people will suffer from indigestion, which is often manifested as abdominal distension, dull pain in the upper abdomen, nausea, belching (belching), bad breath, general malaise, etc. 10% ~ 20% people will have symptoms such as inflammation and peptic ulcer. It can be said that most infected people often know that Helicobacter pylori is lurking in the body through physical examination.

There are many methods to detect Helicobacter pylori, including gastric biopsy urease test, serum antibody test and breath test. Among them, breath test is the most popular because it is convenient, fast, accurate and painless. You can check whether you are infected with Helicobacter pylori by blowing one breath. Before breath test, subjects need to be on an empty stomach for 3 hours.

It should be noted that breath test is only a preliminary test, which cannot replace gastroscopy diagnosis, and positive breath test cannot be equated with "stomach disease" (after all, 70% of infected people have no symptoms). Conversely, if there are symptoms in the stomach and the breath test of Helicobacter pylori is negative, it does not mean that there is no stomach disease. It can only show that these symptoms are not caused by Helicobacter pylori and need further diagnosis by gastroscope.

The human body's resistance has little effect on whether it is infected with Helicobacter pylori, and the key lies in whether it is exposed to the source of infection for a long time.

Helicobacter pylori is mainly transmitted through droplets and oral cavity. Its English name is Helicobacter Pylori, because its tail flagella can move like a helicopter propeller and "swim" from the stomach to the mouth, so it may exist in the saliva and sneeze of infected people. In this way, to prevent the infection or recurrence of Helicobacter pylori, it is inseparable from the old-fashioned problem of "stressing hygiene". Specifically, eat less raw food, share meals as much as possible, use public chopsticks, wash your hands frequently, and couples avoid deep kissing. To prevent diseases from entering the mouth.

Helicobacter pylori has its own preferences, and children under 10 are easy to be targeted and belong to the susceptible population. Among the children infected with Helicobacter pylori in China, 10 years old accounts for 40% ~ 60%, increasing by 3% ~ 10% every year. 10-year-old infected people increased by 0.5% ~ 1% every year. In addition, the infection rate of Helicobacter pylori in children in economically developed countries or regions is low, while the infection rate of children in developing countries and poverty-stricken areas is high.

Some parents like to chew food before feeding their children, or unconsciously try the temperature of food with their own mouths. These habits should be abandoned, otherwise the adult Helicobacter pylori may be transmitted to children. Most people infected with Helicobacter pylori are always in constant contact with the source of infection, such as poor sanitation, polluted water sources, or infected family members. So they are often infected with new Helicobacter pylori. In addition, people's stomach immune system is not strong. Helicobacter pylori has no other competitors in the stomach-other bacteria can't survive in the stomach, so they find their own comfortable place to survive for a long time.

For people who have been infected by Helicobacter pylori and caused corresponding symptoms, the most common clinical treatment is quadruple therapy: proton pump inhibitor (PPI)+ two antibiotics+bismuth, among which amoxicillin/metronidazole+clarithromycin/levofloxacin is the first choice. Generally, it can be cured after one course of treatment 10 ~ 14 days and 1 ~ 2 courses of treatment. However, when choosing the scheme, we have to consider the patient's age, whether there are other diseases, whether there are mixed drugs such as hypertension and diabetes, drug interaction and drug allergy. Most hospitals advocate individualized treatment.

Chen Hong, chief physician of the Department of Gastroenterology, Peking University First Hospital, once wrote that to see whether Helicobacter pylori is completely eliminated, it is necessary to stop taking drugs at least 1 month and check again every year. If it is normal for 2 to 3 years in a row, it means that it is really cured.

In an interview with the media in China, Marshall's team said that Helicobacter pylori generally does not recur after being truly eradicated, and there are few cases of being infected for the second time. The so-called "recurrence" is not really eradicated, because some drugs only inhibit the vitality of Helicobacter pylori, but do not really kill it. If it is not eradicated during the treatment, the problem of antibiotic resistance is likely to greatly reduce the success rate of retreatment. Therefore, the therapeutic goal of Helicobacter pylori is to ensure the success rate of eradication as much as possible. According to official website information of Australian Trade and Investment Committee, in Marshall Infectious Diseases Research Center of Australia, the eradication rate of Helicobacter pylori in patients is over 95% by adopting Marshall hp (English abbreviation for Helicobacter pylori) personalized precision medicine.

The reason why the "eradication rate" is emphasized is that the treatment process of Helicobacter pylori is rather painful, and the drugs are irritating to the digestive tract, which may be repeated to a certain extent, and it is difficult for many patients to really persist. Failure to complete the course of treatment according to the doctor's requirements, irregular medication and reduced dosage may all lead to the failure of eradication treatment.

The Japanese suggest that children should be treated after 12 years old, but there are no guidelines in China. Lu Hong, a professor of gastroenterology at Renji Hospital affiliated to Shanghai Jiao Tong University School of Medicine, believes that the treatment effect of 18 years old will be better. Because with the growth and maturity, some children can heal themselves without treatment, and the most important thing is to avoid long-term contact with the source of infection; In addition, children's tolerance to drugs is poor, and the adverse reactions and side effects in the treatment process are greater, and the process is more painful and difficult to adhere to.

Editor: Ye Xiaoting/Ye Xiaoting @ vip. 163.com

Editor:/cuiyue84452 1292@qq.com Cui Yue