口腔细菌 z-bo 2020-09-23 344

　　Previously, some scientists said that there are about 600 kinds of bacteria commonly found in the human oral cavity. Fortunately, most of these bacteria are beneficial bacteria. However, these bacteria are closely related to human health, and the occurrence of many diseases may be related to The bacterial communities in the oral cavity are related.

　　Recently, scientists from the University of Texas have discovered through research that a healthy oral bacteria may be able to promote the growth of pathogenic bacteria. The researchers pointed out that the bacteria called Streptococcus gordonii in the oral cavity can provide oxygen to the bacteria associated with actinomycetes. Or bacteria can infect teeth, gums and other tissues.

　　So are oral bacteria good or bad? The editor below has made an inventory of this and will learn with everyone!

　　[1] Oral bacteria not only affect dental health but also increase the risk of stroke

　　In a study of acute stroke patients admitted to the hospital, researchers gained a deeper understanding of the relationship between specific types of stroke and oral bacteria. Researchers from Osaka, Japan and the University of Louisville in the United States conducted this study together, and the results were published in scientific reports under the Nature Publishing Group.

　　In this study, researchers found that 26% of patients with intracerebral hemorrhage had a specific type of bacteria in their saliva—CNM-positive Streptococcus mutans. In other types of stroke patients, only 6% of patients can detect the presence of the bacteria.

　　Stroke mainly includes ischemic stroke (caused by obstruction of blood vessels in the brain) and hemorrhagic stroke (caused by rupture of blood vessels in the brain).

　　The researchers also analyzed patients whose MRI test results showed cerebral microhemorrhage. These patients may develop dementia and may also have intracerebral hemorrhage. They found that the saliva contained CNM-positive Streptococcus mutans compared to patients without the Patients with bacteria have a greater number of cerebral microbleeds.

　　[2] Sino-US cooperation found that oral bacteria can increase the risk of esophageal cancer

　　Researchers from the School of Dentistry at the University of Louisville recently discovered that a bacterium called Porphyromonas gingivalis is present in 61% of esophageal squamous cell carcinoma (ESCC) patients. The bacterium itself is related to the occurrence of gum disease. In contrast, the bacterium is only present in 12% of the surrounding tissues of cancer cells, and it cannot be detected in normal esophageal tissue. Related research results were published in the international academic journal Infectious Agents and Cancer.

　　Huizhi Wang, a Chinese scientist who led the research, said: “This research shows for the first time that P. gingivalis infection may be a new risk factor that promotes the occurrence of ESCC, and this bacteria may also become a new organism in the diagnosis of this type of cancer. Scientific markers. If these data are further confirmed, it will show that eliminating a common oral pathogen may help reduce the number of patients with ESCC."

　　It is understood that there are two main types of esophageal cancer: adenocarcinoma and squamous cell carcinoma. Squamous cell carcinoma is more common in developing countries.

　　[3] Researchers found that oral bacteria can cause bowel cancer

　　There are thousands of bacteria in the oral cavity, which is also the reason why diseases are imported from the mouth. However, according to research conducted by Harvard Medical School, there is a kind of suo in the mouth? gan? Fusobacterium ju can even cause bowel cancer. In the past, scientists only knew that this kind of bacteria had a certain connection with bowel cancer, but this time Harvard University researchers found a large number of Fusobacteria in colon adenomas. Although colorectal adenoma is a benign tumor, it may also become malignant. The researchers analyzed that this may be caused by the overreaction of the immune system caused by Fusobacterium.

　　Another study from Case Western Reserve University found that FadA, an adhesion factor on the surface of Fusobacterium, can enter intestinal tumors and cause tumor proliferation. When the molecule is blocked, the development of the tumor is controlled to a certain extent.

　　These two studies revealed a new mechanism of intestinal cancer, and also provided a reference for future drug development.

　　[4] Immunity: oral bacteria protect tumor cells from immune attack

　　Colon cancer patients have an abnormally high number of common oral bacteria, but the potential role of these bacteria in tumor development is not yet clear. A new study published by Cell Press in Immunity shows that oral pathogenic bacteria-Fusobacterium nucleatum can protect a variety of tumor cells from being killed by immune cells. This discovery may open up new avenues for the treatment of cancer patients.

　　Certain bacteria have previously been proven to fight cancer, so the findings here are surprising. Natural killer cells (NK cells) protect the body against various health threats, including viruses and parasites. These cells can also kill tumors, but tumor cells have evolved to avoid this immune response. In the early 1890s, a doctor named William Collet once stated that certain bacteria can enhance anti-tumor immunity. He even successfully treated cancer patients with bacterial extracts. But the relationship between bacteria and tumors is complex, and until now, it is not known whether there are other types of bacteria that have the opposite effect in common cancers: protecting tumors from attack by immune cells.

　　In order to solve this problem, Mandelboim researchers teamed up with the Hadassah College of the Hebrew University to study whether the anti-tumor activity of natural killer cells is affected by Fusobacterium nuclei, which is an oral pathogen and is associated with periodontal disease. It has also been found in human colon tumors.

　　[5] AEM: New oral bacteria can prevent the formation of dental caries

　　English original report: These newly discovered bacteria can help prevent cavities, and scientists want to put them in a pill

　　Keeping the oral cavity clean is not just "brushing with an anti-bacterial toothbrush, and then removing harmful bacteria, leaving behind the bacteria that are beneficial to our oral cavity".

　　But what if there is a more gentle way to limit the proliferation of bacteria? American scientists have identified a new type of oral bacteria that can limit harmful bacteria within a controllable range. This type of bacteria is called "A12" and is essentially a streptococcus. One day in the future, this way of oral cleaning can be achieved by oral administration, as simple as swallowing a small pill.

　　In order to prevent the formation of dental caries and maintain dental health. The PH value of the entire oral cavity needs to be maintained in a stable range. If the oral pH is too acid, many harmful bacteria will grow, which is not good for your white teeth.

　　"When this happens, harmful bacteria will continue to produce acid around the teeth and slowly dissolve the teeth. A simple chemical reaction." Robert Burne, an oral biologist at the University of Florida, said: "Therefore, we are curious about which kind of bacteria can increase the pH of the oral cavity."

　　[6] IJSEM: Common bacteria in the oral cavity can cause serious heart disease and meningitis

　　Recently, researchers from the University of Zurich in Switzerland discovered a common bacterium in the oral cavity. This bacterium may cause serious diseases if it enters the blood. The results of this study were published in the recent international journal The International Journal of Systematic and Evolutionary In Microbiology, this new research discovery will help scientists study how this bacterium causes disease and assess the risk of this bacterium.

　　The bacterium discovered by the researchers is named Streptococcus tigurinus (S. tigurinus, a kind of bacteria of the genus Streptococcus). S. tigurinus is isolated from the blood of patients with endocarditis, meningitis, and spondyloarthritis, and Other bacteria of the genus Streptococcus have high similarities and can reproduce in the oral cavity. Common bleeding from gums provides a convenient way for this bacteria to enter the bloodstream and cause serious infections. Dr. Andrea Zbinden, the researcher who led the research, said: “The identification of S. tigurinus is very important for clinical treatment. It is necessary to accurately identify and study the bacteria for tracking the distribution of the bacteria, as well as the mechanism and pathway of infection, and It can provide some clues for us to find suitable therapeutic drugs for treatment in the clinic.

　　[7] Oral bacteria will be used to diagnose pancreatic cancer

　　News from the American Society for Microbiology, the study found that there is a significant difference between the oral microbial composition of pancreatic cancer patients and healthy controls. This discovery will provide tremendous help in the early diagnosis of pancreatic cancer. Pancreatic cancer is the fourth most fatal cancer, a serious threat to human health. Accurate early diagnosis of pancreatic cancer will greatly increase the survival rate of patients. Unfortunately, an effective technique for early diagnosis of pancreatic cancer has not yet been developed.

　　In this latest study, the research team collected samples from 131 patients, including 63 women and 68 men. Of these 131 people, 14 have been diagnosed with pancreatic cancer, 13 have pancreatic disease, 22 have other types of cancer, and 10 are healthy. The results showed that the composition of the other oral microorganisms (Leptotrichia and Campylobacter) in the patient group with pancreatic cancer was significantly higher than that in the other groups. At the same time, the composition of the other three oral microbes (Streptococcus, Treponema and Veillonella) was significantly lower than that of the other groups.

　　[8] PLoS Pathog: Research reveals how Porphyromonas gingivalis evades immune system-induced inflammation

　　Chronic oral infections caused by pathogens that cause periodontal disease such as P. gingivalis (P. gingivalis) not only cause local inflammation of the gums, leading to tooth loss, but also associated with an increased risk of atherosclerosis. Research published in the journal PLOS Pathogens now reveals how pathogens evade the immune system to not only induce oral inflammation.

　　Like other Gram-negative bacteria, P. gingivalis (P. gingivalis) has an outer layer composed of sugars and lipids. The mammalian immune system has developed to recognize this outer layer of Porphyromonas gingivalis and trigger a multi-pronged immune response. However, due to the "arms race" between pathogens and their hosts, several types of Gram-negative bacteria, including P. gingivalis, partly change their "coats" to avoid host immune defense strategies.

　　Caroline Attardo Genco from Boston University School of Medicine and Richard Darveau of Washington University Dentistry and his colleagues focused on a specific lipid, which is expressed on the outer surface of P. gingivalis, the so-called lipid A. Lipid A interacts with the host immune system. The key regulator TLR4 interacts. P. gingivalis can produce many different versions of lipid A. Researchers hope to figure out how these lipid A "modifies" the immune response and helps pathogens survive and cause local inflammation of the oral cavity and systemic vascular inflammation.

　　【9】Genome Res: Oral environment or change its microbial community structure

　　Recently, a long-term study of human twins by researchers from the University of Colorado Boulder revealed that the community composition of bacteria in their saliva is more affected by environmental factors than genetic factors. The relevant research results were published in the international magazine Genome Research on October 12.

　　In this study, the researchers sequenced the bacterial DNA in the saliva samples of the twins, and compared the sequenced samples with the microbial sequence database. Through analysis and research, scientists can use the microbial communities in the saliva to determine identical twins. Is it more similar than fraternal twins.

　　Researchers also found that the saliva microbiome changes in the early puberty of twins, that is, between the ages of 12-17, which also indicates that lifestyles at different ages can lead to changes in the composition of the microbial community in the saliva. Later, the researchers discovered that many pairs of twins who left home to stay at school had indeed changed the microbes in their oral saliva. And if the twins are separated from each other for a long time, the microbial communities in their saliva will become increasingly dissimilar.

　　The researcher said that this study has established a network to provide conditions for future research on whether environmental impact factors will affect the oral microbial community. With the in-depth research of oral microbiology by researchers in recent years, we can better understand how the oral environment such as alcohol, methamphetamine and even the food we eat affect the balance of our oral microbial community.

　　[10] Microbiology: A new molecule CTLP provides new clues for the treatment of periodontal disease

　　Oral bacteria of the genus Treponema usually accumulate and mix with other oral bacteria to produce destructive dental plaque. Dental plaque composed of bacteria, saliva and food residues is the main cause of gum bleeding and periodontitis. If severe, In the later period, it will develop into severe periodontitis and even tooth loss. The main cause of periodontal disease is the interaction of various bacteria in the oral cavity.

　　Researchers from the United Kingdom recently discovered a CTLP molecule on the surface of the oral bacteria of the genus Treponema. This molecule can recognize different oral bacterial communities and adsorb to the surface of other bacteria. Once CTLP is mixed with the molecules on the surface of other bacteria, it starts to be in the oral cavity. It rages in the blood, inhibits blood coagulation and causes tissue necrosis.

　　Professor Howard Jenkinson led the research. The research paper was recently published in the international journal Microbiology. He said that periodontal disease and gum bleeding are common diseases. This disease affects many people, including the elderly, pregnant women and diabetic patients. Inventing new control methods to control oral bacterial infections requires an in-depth understanding of the microorganisms involved in the infection, how they react, and an in-depth understanding of how these oral microorganisms cooperate to cause dental plaque.