变异链球菌脂磷壁酸的生物学效应

脂磷壁酸是变异链球菌的毒力因子,在变异链球菌致龋过程中发挥着重要作用,在龋病进展过程中诱导牙髓免疫应答。本文就变异链球菌脂磷壁酸的结构和功能,脂磷壁酸在牙周病进展、补体激活、细胞因子产生和牙髓细胞程序性死亡等方面的生物学效应的研究进展作一综述。     

Adsorption of Streptococcus mutans lipoteichoic acid to hydroxyapatite.

Lipoteichoic acid extracted from cells of S. mutans strain BHT exhibited a high affinity for hydroxyapatite. Phosphate ions, fluoride ions and to a lesser extent human saliva inhibited or reversed this adsorption. Extracellular lipoteichoic acid preparations obtained from the supernatant of cultures of the same bacteria exhibited similar properties. It is suggested that lipoteichoic acids could play a significant role in the colonization of teeth by Gram-positive bacteria and thereby contribute to the formation and pathogenicity of dental plaque.     

Streptococcus mutans in plaque after mouth-rinsing with buffers of varying pH value

Abstract – After a period of mouthrinsing with a phosphoric buffer solution with low pH the proportional distribution of Streptococcus mutans in plaque from occlusal retention sites was significantly higher than after a control period. This indicates that colonization with S. mutans may be favored or that other microorganisms competing with S. mutans are inhibited under these circumstances.     

Prevalence of Streptococcus mutans with different colonial morphologies in human plaque and saliva

Abstract – Plaque and saliva samples were obtained twice from 58 children at an interval of 1 year and examined for the prevalence of Streptococcus mutans on Mitis salivarius (MS) and Mitis salivarius bacitracin (MSB) agar. Two types of S. mutans colonies with different colonial morphologies were seen on both media. They were serologically identified as serotypes c/e/f and d/g respectively. The first type, morphogroup c/e/f, had the typical "frosted-glass" appearance. It was the most prevalent and was found in 97% of the children. The second type, morphogroup d/g, had a creamy marzipan consistency with a dull, granular surface, gray to brown in color and often with some liquid around or on top of the colony. Group d/g was detected in 21 children (36%) and then together with colonies of group c/e/f. Children infected with single or multiple morphogroups of S. mutans generally harbored the same groups 1 year later. There was a significant positive correlation between the proportion of S. mutans in plaque and their numbers in saliva.     

Effect of chlorhexidine on the relative proportions of Streptococcus mutans and Streptococcus sanguis in hamster plaque

abstract — The effect of chlorhexidine on the proportions of Streptococcus mutans and Streptococcus sanguis in plaque was studied in hamsters fed a diet containing 28% sucrose. In animals given chlorhexidine in their drinking water for 10 d a decrease in the population of S. mutans and an increase of S. sanguis occurred in the plaque. Following the removal of chlorhexidine the population of S. mutans increased again in the presence of sucrose and the number of S. sanguis returned to initial values. When animals were given a sucrose-free diet the low proportion of S. mutans observed following the short-term chlorhexidine period persisted. These data indicate that there is an inverse relationship between the number of S. sanguis and S. mutans in plaque and that the sensitivity in vivo of S. mutans to chlorhexidine can be used to suppress the population of S. mutans with a concomitant rise in the proportion of S. sanguis .     

Effect of a fluoride-containing varnish on Streptococcus mutans in plaque and saliva

Abstract – The effect of topical application of a fluoride-containing varnish, Duraphat®, on the level of Streptococcus mutans in saliva and in dental plaque was investigated in schoolchildren. Samples of saliva and pooled buccal plaque were taken before varnish application and 4, 10 and 21 d after treatment. Fluoride varnish treatment with or without a preceding dental prophylaxis had no significant effect on the plaque and salivary levels of S. mutans. The findings suggest that the caries-reducing effect of fluoride varnish cannot be explained by an alteration of the incidence of 5. mutans in dental plaque or in saliva.     

粪肠球菌和变异链球菌脂磷壁酸的生物学活性

粪肠球菌是难治性根尖周炎根管内的主要致病菌。变异链球菌是引起龋齿的主要致病菌。粪肠球菌和变异链球菌的毒力因子脂磷壁酸（LTA）皆可促进细胞分泌炎症因子,引发炎症反应,促进根尖周牙槽骨吸收;有助于细菌黏附于牙体表面和生物膜的形成。粪肠球菌和变异链球菌LTA在细菌致病性方面起着重要的作用,但其机制尚不清楚。因此,研究LTA的致病机制及分子结构,旨在实现阻断其致病通路、降低其致病性。     

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目的    探讨2岁儿童口腔菌斑中变形链球菌（变链菌）的检出率和蔗糖依赖性黏附能力。方法    选取广州市郊花都区2008年8—9月于入托前在妇幼保健院儿保科体检的2岁高龋（龋失补牙数≥ 5）及无龋（龋失补牙数 = 0）儿童各32名,形态学、生理生化学方法对其牙菌斑进行分离鉴定;采用分光光度比浊法,检测高龋儿童和无龋儿童变链菌临床分离株对玻壁的黏附情况。结果    64名儿童中变链菌的检出率为56.25%,高龋组儿童变链菌检出率（75.00%）显著高于无龋组儿童（37.50%）,差异有统计学意义（P < 0.05）。生化鉴定获得高龋儿童75株和无龋儿童34株变链菌临床分离株。在含1%蔗糖的培养基中,高龋组变链菌分离株对玻壁的黏附比为0.58 ± 0.15,略高于无龋组0.56 ± 0.13,但两组间差异无统计学意义。结论    2岁儿童变链菌检出率与高发龋相关,而未见其蔗糖依赖性黏附力对龋病高发有影响。     

Salivary Streptococcus mutans and caries prevalence in Brazilian schoolchildren

The aim of the present study was to determine the levels of salivary Streptococcus mutans in Brazilian schoolchildren, and its possible correlation with caries prevalence. A positive correlation between different levels of S. mutans and caries prevalence was observed, individuals with high levels of S. mutans (greater than 100 colonies) had a DMFS significantly higher than those with low or no detectable S. mutans (0, 1-20, 21-40 colonies).     

Adaptation by Streptococcus mutans to acid tolerance

Our previous continuous culture studies with strains of Streptococcus mutans have indicated that the organism has the capacity of adapt to growth in acidic environments. This study was undertaken to examine this question in more detail. S. mutans Ingbritt and the phosphotransferase system (PTS)-defective mutant, S. mutans DR0001/6, were grown in continuous culture at pH 7.5 and 5.5 or 5.1, and the pH optimum for glucose uptake and glycolysis and the capacity of the cells to generate pH gradients were determined over the pH range 4.5 to 8.0 with steady state, washed cells. In addition, the proton permeability of the cells was measured over the pH range by an acid pulse technique. The results indicate that the pH optimum for glucose uptake by S. mutans Ingbritt grown at pH 7.5 was 7.5 and this optimum shifted to 7.0 and 6.0 for cells grown at pH 5.5 and 5.1, whereas with the S. mutans DR0001/6, the optimum shifted from 7.5 to 7.0 for the pH 5.5 cells. A similar shift in the pH optimum for glycolysis was observed for the 2 strains, and this was particularly pronounced for cells incubated with glucose in the presence of gramicidin to dissipate proton gradients. The capacity of the cells to generate pH gradients was related to their metabolic activity, and although larger gradients were not formed by the pH 5.5 cells, these cells were nevertheless capable of maintaining gradients at a lower pH; S. mutans DR0001/6 generated 2-fold larger pH gradients at pH 5.5 than S. mutans Ingbritt.(ABSTRACT TRUNCATED AT 250 WORDS)     

变异链球菌蛋白质组研究进展

变异链球菌是口腔龋病的重要的病原菌之一。随着实验新技术的不断涌现,对于变异链球菌的研究,也从形态学、生化鉴定、基因等的水平,上升到蛋白质组水平。变异链球菌的蛋白组随着生长环境、生长状态和菌珠的变化而变化。本文综述了近年来变异链球菌蛋白质组的研究状况。     

Streptococcus mutans establishment and dental caries experience in children from 2 to 4 years old

Abstract – 39 children were studied longitudinally at the age of 2, 3, and 4 yr for the colonization of S. mutans in plaque and saliva and for caries experience. S. mutans was found in 38% of the children, and the predominant serotype group was c/e/f. A total of 16 children got caries before the age of 4. Children who harbored S. mutans in their plaque at the age of 2, appeared to be the most caries-active individuals. Their caries index values (number of decayed, missed and filled surfaces, dmfs = 10.6±5.3) at the age of 4 differed significantly from the values of children who harbored S. mutans later (dmfs = 3.4±1.8,P<0.005) or remained free from S. mutans infection (dmfs = 0.3±1.1, P<0.0003). It was thus concluded that the early establishment of S. mutans in the plaque of primary incisors indicated early and extensive caries attack in young primary dentition.     

Ultrastructural visualization of the adherence of Streptococcus mutans and Streptococcus salivarius to hydroxyapatite

Abstract – S. mutans and S. salivarius adherence to saliva-coated and saliva-uncoated hydroxyapatite was studied by transmission and high resolution scanning electron microscopy. No difference was observed between the saliva-coated and saliva-uncoated study series of adherence. The attachment of individual bacteria to apatite crystals was found to be mediated by cell wall projections. These electron-dense structures were characteristically well formed in S. mutans, and even in S. salivarius the projections appeared to link the bacteria to the apatite. The site of attachment in the bacterial cell wall was always at the division area. We suggest that the possible metabolic activity at the cell wall division site, therefore, also works in the adherence process.     

Streptococcus mutans-like bacteria from human dental plaque in a Sri Lanka (Ceylon) population

Abstract – This paper reports on the presence of low numbers of Streptococcus mutans among the oral streptococci present in human dental plaque in a Sri Lanka (Ceylon) population, where the caries activity is low and a low sucrose intake is combined with the presence of heavy plaque deposits. Plaque samples of unknown age were collected from 10 individuals in a tea estate, and another 10 samples were collected from dental students 19 days following interruption of oral hygiene. Of 670 such strains of oral streptococci studied, none showed typical "frosted glass" colony morphology on Mitis Salivarius agar. However, when subjected to physiological tests 14 of them were classified as S. mutans.     

Streptococcus mutans, lactobacilli and dental health in 13–14-year-old Swedish children

Abstract The dental health and the prevalence of Streptococcus mutans and lactobacilli were examined in 101 13–14-year-old children. The average number of decayed (incipient caries) and filled surfaces (DFS) was 10.1 and 12.8, respectively. S. mutans was not detected in 11% of the children while 21% had 10⁶ or more S. mutans per ml saliva. Lactobacilli were not found in 21% of the children whereas 11% had 10⁵ or more lactobacilli per ml saliva. Statistically significant correlations were found between S. mutans and lactobacilli, S. mutans and DFS, lactobacilli and DPS and S. mutans plus lactobacilli and DFS. Increasing numbers of S. mutans and lactobacilli, alone and in combination, were associated with an increased caries frequency.     

固定矫治中牙面变形链球菌附着状况及结扎材料对其影响的研究

目的研究托槽粘接前后牙面变链菌的附着状况及结扎材料对变链菌附着的影响。方法随机在28例患者牙弓一侧用不锈钢丝结扎，另一侧用弹力圈结扎。于粘接前和粘接后1、3、7、11、15、19周进行变链菌和总厌氧菌培养。比较同种结扎材料粘接前后和同一时间点不同结扎材料间变链菌计数和百分比的差异。结果粘接后两种结扎材料侧变链菌计数和百分比均增加，与粘接前差异有统计学意义（P〈0．01）。弹力圈结扎侧粘接后1周、3周的变链菌百分比（1．83％、1．87％）分别高于不锈钢丝结扎侧（1．78％、1．82％），差异有统计学意义（P〈0．01，P〈0．05）。结论托槽粘接后个体患龋概率增高。在矫治中推荐使用不锈钢结扎丝结扎。     

Proportions of Streptococcus mutans, lactobacilli and Actinomyces spp in root surface plaque

Abstract – The incidence of Streptococcus mutans, lactobacilli and Actinomyces was examined in root surface dental plaque from 24 subjects with root surface caries and in 24 subjects with exposed root surfaces as a consequence of periodontitis but without root surface caries. Plaque was collected from the most posterior teeth in each quadrant: in the caries group from carious lesions and in the periodontitis group from buccal root surfaces. There were significantly higher proportions of S. mutans and lactobacilli in dental plaque samples taken from subjects suffering from root surface caries than in samples from subjects without root surface caries. The level of the group A. viscosus/naeslundii in the periodontitis group was higher than that found in the root surface caries group, but the difference was not statistically significant.     

Effect of SnF2, administered as mouthrinses or topically applied, on Streptococcus mutans, Streptococcus sanguis and lactobacilli in dental plaque and saliva

Abstract – Mouthrinsing with SnF₂ reduced the Streptococcus mutans population in plaque and saliva and the proportion of Streptococcus sanguis in plaque. The effect was of short duration: 2 weeks after treatment the values of S. mutans in plaque and saliva were even higher than the pretreatment values. Topical SnF₂ applications reduced the S. mutans population in plaque and saliva but did not reduce the proportion of S. sanguis in plaque. The eflect was more prolonged: 4 weeks after treatment the S. mutans population in interproximal plaque remained significantly reduced and the salivary levels of the organism had not fully returned to pretreatment levels. Both SnF₂ treatments significantly increased the salivary levels of lactobacilli. The values of laclobacilli in saliva remained signilicantly increased 4 weeks after the SnF₂ mouthrinsing but had almost returned to pretreatment levels within 2 weeks after the topical SnF₂ applications. The findings suggest that the cariogenic potential of dental plaque is differently affected depending on whether a drug is administered as a mouthrinse or is applied topically.     

Streptococcus mutans in plaque and saliva after mouthrinsing with SnF2

Abstract – Mouthrinses with SnF2 in 11 subjects significantly reduced ( P <0.01) the total colony forming units (CFU) count and the numbers of Streptococcus mutans and Streptococcus sanguis in plaque. The numbers of S. mutans and S. sanguis were significantly more reduced than was the total CFU count. After rinsing with SnF2 S. sanguis was present in 97% and S. mutans in only 42% of plaque samples from tooth surfaces where they were detected after rinsing with water. SnF2 also significantly reduced ( P <0.01) the number of S. mutans in saliva. Mouthrinses with NaF did not markedly affect the number of S. mutans either in plaque or in saliva.     

Streptococcus mutans and dental caries in urban and rural schoolchildren in Thailand

Two groups of Thai schoolchildren aged 11-13 yr were examined for dental caries, dental fluorosis and Streptococcus mutans. One hundred children lived in an urban district, Bangkok, and 71 children in a rural district, Petchaboon. Saliva samples were analyzed for S. mutans by the spatula method. The fluoride content of the drinking waters was also determined. The prevalence of caries, diagnosed according to WHO, was 89% in Bangkok and 18% in the rural district. Mean DMFT was 3.46 and 0.38 respectively. S. mutans was found in 98% of the urban children and in 82% of the rural. The differences in distribution between S. mutans and DMFT classes were statistically significant for the total sample. Mild fluorosis was present in some of the rural children.