Helicobacter pylori: Small bacteria, big threat, how much do you know?

Author: Fan Ruirui, PhD, Xiang'an Hospital Affiliated to Xiamen University

Reviewer: Chen Jin, Chief Physician, First Affiliated Hospital of Chongqing Medical University

My name is Helicobacter pylori, you can also call me Hp (Helicobacter pylori). Although it is small in size, it poses a huge threat to human health. The news that "the average infection rate of Helicobacter pylori in my country is as high as 59%" was once on the Internet hot search and became an "Internet celebrity". Although many people know me now, some people are not very familiar with me.

I am a monopolar, multi-flagellated, blunt-ended, spirally curved Gram-negative bacillus, 2.5 to 4.0 microns long and 0.5 to 1.0 microns wide. I have specific requirements for the oxygen content in the environment and must survive at an oxygen content of 5% to 8%. I cannot survive in the atmosphere or in an absolutely anaerobic environment. I am the only bacterium that can survive in the human stomach for a long time, and humans are my only natural source of infection. In 1989, I was officially named "Helicobacter pylori" by the World Health Organization's Bacterial Nomenclature Committee. In 1994, I was listed as a Class I biological carcinogen by the World Health Organization. It has now been confirmed that my presence is a major risk factor for gastric ulcers and gastric cancer, especially my detection rate in gastric ulcer patients is as high as more than 80%.

Today, I am parasitic on Xiao Wang, with great ambitions, and want to expand my "territory". I usually hide in Xiao Wang's saliva, dental plaque, stomach and feces, and mainly spread through his saliva or feces. Among them, oral transmission is my main transmission route. Xiao Wang often does not use serving chopsticks during dinner parties, which is the best time for me to expand my "territory".

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During a dinner party between Xiao Wang and his friends, I targeted Xiao Zhao as my target for expanding my "territory" and successfully entered Xiao Zhao's stomach through saliva, which then started my "expansion journey":

1. Colonization: After arriving at Xiao Zhao’s stomach, I quickly “settled down” on the gastric mucosa, especially the gastric antrum which became my main “stronghold”.

2. Survival: I use the urease produced by my own body to break down urea into ammonia and carbon dioxide. This process effectively neutralizes stomach acid and ensures that I can survive in the acidic stomach environment.

3. Pathogenicity: After settling in the gastric mucosa, I triggered an inflammatory reaction in the gastric mucosa, causing Xiao Zhao to have stomach pain, indigestion and other symptoms. If I could stay here for a long time, it might further develop into gastric ulcers and even induce gastric cancer.

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Under my persistent attack, Xiao Zhao's gastric mucosa was finally damaged. In addition, Xiao Zhao's daily life was irregular and he was an absolute master of staying up late. It didn't take long for Xiao Zhao to develop bad breath, periodic abdominal pain, acid reflux, belching and other symptoms. Xiao Zhao couldn't stand it and went to the hospital for treatment. The doctor suggested that he do a urea breath test first, because this detection method is non-invasive, painless, accurate, and has low radiation, and the results can be obtained in about half an hour. The result showed Hp (+), and that's how I was discovered.

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Later, Xiao Zhao's gastroscopy showed that I had successfully dug a "swimming pool" in his stomach - the ulcer, a circular building with a diameter of less than 2 cm. I usually choose to "dig a swimming pool" on the lesser curvature of the stomach. I dig the "swimming pool" very deep, reaching the muscle layer or even the serosal layer, and the surrounding mucosal folds are distributed radially from the ulcer to the surrounding area. In the active stage, the following four layers of tissue structure can be seen under the microscope at the bottom of the ulcer, namely ① inflammatory exudate layer, ② necrotic layer, ③ granulation tissue layer, and ④ scar layer.

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The doctor also told Xiao Zhao that I, Helicobacter pylori, was the "culprit" of his gastric ulcer and that I must be eliminated before there is a possibility of cure. I "shuddered" after hearing this. Under the doctor's advice, Xiao Zhao adopted a quadruple treatment plan: proton pump inhibitor + bismuth + 2 antibacterial drugs. The doctor seriously reminded him: If you do not strictly follow the doctor's advice and take the medicine at will, it may cause a variety of complications, such as bleeding, perforation, pyloric obstruction and even cancer. Among them, bleeding is the most common, and perforation is the most dangerous. Only by following the doctor's advice and taking the medicine on time and in the right amount can you recover. Generally, after 10 to 14 days of standardized treatment, I will be eliminated. After taking the medicine for 14 days, Xiao Zhao's symptoms gradually disappeared, and he was relieved after going to the hospital for a reexamination to confirm that I was "eradicated". In this battle with me, Xiao Zhao won! Finally, the doctor also taught Xiao Zhao many measures to prevent me from "coming back" again: ① Eat less takeout, promote the system of separate meals, and disinfect tableware regularly; ② Maintain oral health and quit smoking; ③ Avoid consuming too much irritating food to reduce damage to the gastric mucosa.

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My journey in the human body has come to an end. Although I have temporarily lost the battle with Xiao Zhao, this is only a fragment of a long battle for health. The Hp family behind me is huge and complex. They lurk in different forms and in different environments, ready to launch new challenges at any time.

Therefore, it is crucial for each of us to understand the "big threat" behind the "small bacteria". This requires us to continuously enhance our scientific understanding of Hp and its family and master effective prevention and intervention measures. At the same time, enhancing public health awareness and strengthening personal hygiene habits are also important lines of defense against the invasion of such microorganisms.