Streptococcus mutans S. Mutans

Streptococcus mutans, a gram-dyed positive bacterium, is one of the most important components of the genus Streptococci, which is the largest proportion of the oral natural flora. Caries is a bacterial infectious disease occurring in the hard tissue of the tooth, the highest incidence in oral diseases. Streptococcus mutans is the main pathogenic bacteria of dental caries, and its transmission methods are various, including maternal transmission, paternal transmission and other transverse propagation modes.Chinese nameStreptococcus mutanssubordinateGram-Dyed positive Neisseria gonorrhoeaefeaturesThe largest proportion of natural oral florafunctionOne of the main components of dental plaque Catalog

1 cause of disease

2 stop plaque

saliva streptococci

? FruA

3 attribute

4 first argument

5 matriarchal propagation

6 Horizontal propagation

7 epilogue

1 cause of illness edit It is one of the most important strains of Streptococcus in oral natural flora, which is positive for three-gram staining. Repeated studies have confirmed that Streptococcus mutans can cause animal models of experimental caries in rodents and primates, and there is evidence that this bacterium is closely related to human caries. According to the cell wall antigen composition of Streptococcus mutans, there are 8 kinds of serum type (a~h) and 6 species (Ⅰ~ⅵ) of guanine (G) and cytosine (C) in the DNA of bacterial cells. In Streptococcus mutans group, Streptococcus mutans and Streptococcus distant (STREPTOCOCCI) were closely related to the occurrence of human caries. The human mouth is filled with germs. In hot and humid conditions, more than 700 species of bacteria thrive in the mouth, including Streptococcus mutans, one of the main components of plaque. Streptococcus mutans adsorbed on a layer of teeth, forming a so-called "biofilm." They consume sugars, produce acids, corrode the enamel layer of teeth, and cause cavities. Other bacteria are like more friendly guests. For example, in 2009, scientists found that saliva streptococcus can reduce the accumulation of Streptococcus mutans biofilm, which exists in the tongue and other soft tissues of the mouth.2 blocking plaque editing Senpuku, a biologist at Japan's National Institute of Infectious Diseases, Tokyo, and colleagues want to know what substances have given saliva streptococcus a powerful resistance to tooth decay. The researchers used chromatography, a method of separating the various molecules in a mixture based on charge or size, to isolate different proteins from the saliva streptococcus samples. The researchers then blended each protein with Streptococcus mutans to measure which of the cultures formed the thinnest biofilm on the laboratory sheet. Protein Frua is an enzyme that decomposes complex sugars, which is the most powerful biofilm blocker.Saliva StreptococcusFruA researchers also found that a form of FruA, produced by the common fungus Aspergillus niger, is a readily available product that has the same good effect in preventing plaque formation. Although the amino acid sequence of this commercial Frua is somewhat different from that of the saliva Streptococcus frua, commercial Frua still works. Senpuku said that this could lead to the rapid development of toothpaste containing Frua.FruAThese findings are reported in the Journal of Applied and Environmental Microbiology, however, this does not mean that you are allowed to eat all the sugars you want to eat. When researchers increased the concentration of sucrose in a mixture of Streptococcus frua and Streptococcus mutans, the beneficial bacteria lost the ability to prevent biofilm formation. The authors of the study wrote that the observations could explain why a 1996 study found that Frua in mice contributed to the formation of cavities. Mary Ellen David, a biologist at the Forsyth Institute in Cambridge, Massachusetts, agreed that the findings could lead to the development of higher quality toothpaste. However, she pointed out that the development task would not be so easy: "A huge challenge is to find a formula that will keep the enzyme active on your favorite grocery store shelves," he said.3 feature editing The strong caries of Streptococcus mutans is mainly determined by its acidity and acid resistance. Streptococcus mutans, which survives in plaque, can quickly ferment a variety of carbohydrates to produce a large amount of acid, which can reduce the local ph to less than 5.5. Streptococcus mutans has strong acid resistance and can continue to live merged acid at ph 4.5. Local ph decreased for quite a long time, avoiding the buffering effect of saliva, which resulted in local hard tissue demineralization, and the process of caries began. Streptococcus mutans can synthesize extracellular dextran, fruit polysaccharide and intracellular polysaccharides with sucrose as substrate. Dextran mediates the adhesion of bacteria and promotes the formation of plaque, which is an important caries-causing virulence factor. The water-soluble glucan, oligosaccharide and intracellular polysaccharide synthesized by the bacterium can also be used as metabolic substrates to provide energy and enhance the caries resistance. Streptococcus mutans surface protein and lipid phosphate wall acid are the surface binders of bacteria, which combine with different receptors in the acquired membrane to promote the formation of adhesion and plaque of the bacterium. Streptococcus mutans is not only the main pathogenic bacteria of crown caries, but also the main pathogenic bacteria of root caries.4 First argumentation editor As early as the 1960s, Keyes first argued that caries is an infectious, contagious disease. Streptococcus mutans (Streptococcusmutans,ms.) is currently considered one of the most important pathogens in human caries. The transmission and acquisition of Streptococcus mutans has always been a matter of concern to people.5 Matriarchal transmission edit The idea of maternal transmission in MS is based on the similarity of the bacteria found in the oral cavity of the mother and infant. The stable colonization of MS in human oral cavity requires the presence of a tooth or non-dandruff surface, so the baby will only get Ms after the tooth has erupted. A large number of genetic fingerprinting studies show that in different populations, the degree of similarity between the child and the mother's Ms genotype is different, depending on the cultural background, the close contact and age of the family members. Ersin the study of 8 high-level MS in Turkish non-irritating saliva (child age of 2~3岁) found that all children with their mothers had similar genotypes to Ms. Lis and other 20 pairs of children who already have MS in the oral cavity (3~4岁) and their mothers were tested, and 20 of the 16 pairs (80%) of the mother and child were found to have similar genotype, suggesting that Ms was a high-prevalence phenomenon in the population. Studies have shown that the primary way to obtain Streptococcus mutans early in the human mouth is from the mother to the child's vertical transmission. A 7-year mother-to-child follow-up survey of 15 children of 0~7岁 found that 9 of the 26 genotypes detected in the oral cavity were in full agreement with their mothers, especially in children, where some of the newly discovered genotypes and Lindquist were present and then lost in their mothers. Emanuelsson collected dental plaque from 25 3-year-olds and their mothers and 18 fathers in the Swiss family, and showed that 6 children had exactly the same genotype as their mother. Spolidoriodmp and other 22 Brazilian family members obtained from the chain strains of the AP-PCR genotyping, the results showed that 12 families have the same genotype of mother and child. Kozaik collected dental plaque specimens from 20 Japanese families (20 couples and their 36 children) and analyzed that 36 of the 70 genotypes found in the child were the same as their mothers. The analysis of 400 strains of the 10 4~5岁-aged children and their mothers in a kindergarten in Anhui province showed that 4 of them found 1 common genotypes and 1 found 2 total genotypes in their mother and child. However, the desoetjj of 21 children with cleft lip and palate and their mother's saliva samples were cultured by PCR to identify Ms isolates, and only 38% of the mother and child were found to have the same PCR genotyping. The findings suggest that Ms transmission between children and mothers with cleft lip and palate is not common, and may be associated with preventive treatment of children with cleft lip and palate and their mothers. In the study of the distribution of the chain bacteria between 20 pairs of 1~2岁 children and grandparents in Beijing city, 11 young children who detected the chain bacteria, 9 had similar genotype with grandparents, and only 3 children had similar genotype with their mother, which may be related to the daily caregivers of the family. Above by genotyping, chromosome DNA fingerprint analysis and other studies have suggested that children through the placenta and breast milk from the mother's passive immunity, may selectively make certain strains colonization, the maternal origin of the strains have a preference. The propagation mode of 2MS's paternal transmission is not unique, and most of the previous studies have shown that MS is mainly transmitted along the matriarchal, but in recent years many scholars have made great progress in the study of the paternal transmission of Ms. Ersinz, who studied the high-level MS in 8 pairs of Turkish mother and child and 3 of them in the saliva (child age of 2~3岁), showed that the child had the same genotype as the parent. The results of SPOLIDORIODMPB, which were obtained from 22 Brazilian family members, showed that the father and son of 3 families had the same genotype. The analysis of 192 strains of chain bacteria collected from 16 families (16 pairs of mother and son, 7 sons and fathers) revealed that there were at least 14 types of ribose in 1 pairs of Kohler, and 6 were of the same ribose type. In China's Hubei province, the Swedish scholar Redmoi 18 children 3 years old family saliva and dental plaque after the analysis, the results 11 family members at the same time isolated ms,3 family father and son of the same, 2 families of all three have a consistent genotype of the strain, MS in the proportion of parent-child transmission is higher. Kozaik collected dental plaque specimens from 20 families in Japan (20 couples and 36 children), and analyzed that 22 of the 70 genotypes found in the child (31.4%) were the same as the father's. The result shows that fathers and others are like mothers who are the source of the spread of the chain bacteria. China's Xu Cobin and other scholars selected a kindergarten in Shenyang, China, 10 children and their fathers as the object of study, take father non-irritating whole saliva and children's dental plaque, the results of the total separation of children 16 genotype, 3 and father of the same. The results of this experiment support the idea of the spread of Ms among Chinese family and fathers. However, Emanuelsson collected 18 cases of 3-year-old children and their father's cheek surface and the surface of the dental plaque, although 2/3 of the fathers have high or high MS level, but the results did not find that the children's genotype and father's similarity.6 horizontal propagation edit A large number of studies have shown that MS is transmitted in many forms. In the same environment over a long period of time, the exposure to parental contact is reduced, and MS is likely to spread horizontally during the window of the infection. For couples, early studies have shown that the phenomenon of MS transmission among adults, both in animals and in clinical studies, show that bacteria are inoculated after adulthood and bacteria are difficult to resettle. In the above-mentioned Emanuelsson investigation of whether there is a family similarity of Streptococcus mutans in the Swiss family (collection of 25 children aged 3 and their mother, including 18 fathers on the cheek surface and the surface of the dental plaque), there was no matching genotype between the 11 couples. Kozaik They collected plaque specimens from 76 of the 20 Japanese families (20 couples and their 36 children), and the results showed that only two couples had the same genotype and had less chance of transmission. But a similar genotype was found among spouses in the study of high-level MS in non-irritating saliva of 8 pairs of Turkish mothers and fathers, 3 pairs of sons and Ersin. NIE collected 11 pairs of Chinese family couples in the buccal and dental plaque, and the clinical isolates of the chain strains of bacteria genotyping and genotyping, 3 months later repeat this process. The results showed that a couple of Streptococcus mutans had the same genotype in the first Test, but in the second Test it was found that the husband had lost the gene-linked strain. However, another couple who did not find the same genotype in the first test found the same genotype 3 months later. This information shows that couples have the opportunity to obtain strains of Streptococcus mutans from each other, and the results show that there is a spread of the chain bacteria among the adults in the family, but it is not easy for the transmission strains to exist in the mouth of the infected person for a long time. The above-mentioned spolidoriodmp, among others, showed that 7 pairs of twins had similar genotypes in different trials of 22 Brazilian families from hereditary aspects to differentiate the chain strains. There are also many scholars think that children in kindergartens can appear in the spread of Ms. Mattos-granerro isolates Streptococcus mutans from the oral cavity of a Brazilian nursery child and carries out genotyping. Of the 24 children, there were about 2~5 strains of Streptomyces isolates, about 29% of which carried 2 or three genotypes. The presence of paired chain strains among children in the same nursery showed a level of spread between them. Our country's about and so on a kindergarten 24 3~4岁 kindergarteners Children carries on the research, has detected 29 different genotypes the chain bacterium, through the DNA fingerprint analysis, has 2 kinds of genotype in 11 kindergarteners children's oral cavity to have the duplicate detection. But similar experiments found that the level of the chain bacteria in day-care children was significantly smaller than that of kindergarteners children. RENATAMG, who also studied 35 ms-infected children from 9 kindergartens in 3 cities, found 5 children with the same variable-chain genotype in the same kindergarten as the 76 strand isolates. In addition, the phenomenon of transmission outside the home has also been reported, KulKARNIGV's study of 5 families in Canada found that only 13% (3 types) of 23 types of oral chains in 7 children were from mothers or fathers, and 87% were outside the home, suggesting that external sources of the family were also important. 7 Conclusion editor Caufield PW proposed that the initial settlement of the infant chain had an obvious infection period, beyond which the chain was difficult to settle. The susceptibility period of MS infection decreased with age, until 5 years old, the microbial ecosystem of deciduous plaque was basically stable. The young stage is a critical period for obtaining MS, known as the "duration of infection (windowof infectivity)", for an average period of about 26 months. The oral flora gradually stabilized with time, and the difficulty of Ms Colonization increased. Therefore, in the MS susceptibility period to reduce parental saliva ms level measures, such as the use of chlorhexidine gel, fluoride coating, etc., can effectively reduce the chance of infants infected with MS, and subsequently reduce the occurrence of dental caries.

Streptococcus mutans S. Mutans