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

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 chlorheximide can be used to suppress the population of S. mutans with a concomitant rise in the proportion of S. sanguis.     

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.     

蔗糖环境对寡发酵链球菌与变异链球菌双菌种生物膜形成的影响

目的探讨蔗糖环境对寡发酵链球菌与变异链球菌双菌种生物膜形成的影响,并与血链球菌和变异链球菌的双菌种生物膜形成进行比较。方法运用菌落计数法观察蔗糖环境下唾液包被的玻璃生物模型中单/双菌株寡发酵链球菌,变异链球菌和血链球菌24 h生物膜形成情况;运用激光共聚焦显微镜观察蔗糖环境下寡发酵链球菌,变异链球菌和血链球菌单/双菌株生物模型中24h生物膜形成厚度。结果无糖环境下,单菌株模型中,菌落数:血链球菌(55.67±5.36)>变异链球菌(53.48±2.63)(P>0.05)>寡发酵链球菌(46.24±2.34)(P<0.05);生物膜厚度:血链球菌(17.23±3.82)>变异链球菌(15.16±4.21)(P>0.05)>寡发酵链球菌(10.54±4.37)(P<0.05)。双菌株模型中,变异链球菌菌落数降低幅度:血链球菌组>寡发酵链球菌组(P<0.05)。生物膜厚度:血链球菌组(8.12±2.82)<寡发酵链球菌组(11.27±3.55)(P<0.05)。蔗糖环境下,单菌株模型中,菌落数:变异链球菌(58.54±2.74)>血链球菌(51.87±5.35)>寡发酵链球菌(48.57±3.05)(P<0.05)生物膜厚度:变异链球菌(20.63±5.71)>血链球菌(13.37±4.93)>寡发酵链球菌(12.45±4.62)(P<0.05)双菌株模型中;变异链球菌菌落数降低幅度,寡发酵链球菌组>血链球菌组(P<0.05),生物膜厚度:寡发酵链球菌组(6.67±2.19)<血链球菌组(10.45±2.72)(P<0.05)。结论外界糖环境影响寡发酵链球菌和血链球菌对变异链球菌的抑制作用,蔗糖环境下,寡发酵链球菌的抑制作用强于血链球菌。     

Effect of penicillin on Streptococcus mutans, Streptococcus sanguis and lactobacilli in hamsters and in man

The effect of penicillin on the number of oral Streptococcus mutans, Streptococcus sanguis and lactobacilli in hamsters and in man was investigated. This is of interest as S. mutans and lactobacilli are involved in the carious process while S. sanguis is not. Hamsters infected with both S. mutans and S. sanguis or only S. sanguis received penicillin in their drinking water for 14 d. The treatment reduced the proportion of S. mutans and S. sanguis in dental plaque to undetectable levels. After the penicillin treatment the population of S. mutans and S. sanguis gradually increased. In man, the effect of oral penicillin therapy was examined in 21 adults with more than 2 X 10(5) S. mutans per ml saliva. The penicillin treatment had almost no effect on the numbers of S. sanguis and lactobacilli, but a pronounced decrease in the number of S. mutans was observed. The duration of this effect, however, was short. Consequently, such treatment alone is of limited value for the control of the oral infection of these microorganisms.     

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.     

Effect of penicillin on Streptococcus mutans, Streptococcus sanguis and lactobacilli in hamsters and in man

Abstract – The effect of penicillin on the numbers of oral Streptococcus mutans, Streptococcus sanguis and lactobadlii in hamsters and in man was investigated. This is of interest as S. mutans and lactobacilli are involved in the carious process while S. sanguis is not. Hamsters infected with both S. mutans and S. sanguis or only S. sanguis received penicillin in their drinking water for 14 d. The treatment reduced the proportion of S. mutants and S. sanguis in dental plaque to undetectable levels. After the penicillin treatment the population of S. mutans and S. sanguis gradually increased. In man, the effect of oral penicillin therapy was examined in 21 adults with more than 2 × 10⁵ S. mutans per ml saliva. The penicillin treatment had almost no effect on the numbers of S. sanguis and lactobacilli, but a pronounced decrease in the number of S. mutans was observed. The duration of this effect, however, was short. Consequently, such treatment alone is of limited value for the control of the oral infection of these microorganisms.     

Effects of chlorhexidine and iodine on in vitro plaques of Streptococcus mutans and Streptococcus sanguis

Abstract – Both chlorhexidine and iodine showed greater antimicrobial effect on in vitro grown S. mutans plaque than on plaque composed of S. sanguis . One treatment with iodine for 8 min inhibited the acid production of S. mutans plaque whereas S. sanguis plaque required 20 min to be similarly affected. In contrast one treatment with chlorhexidine for up to 20 min did not completely inhibit the acid production of plaque of either microorganism. Repeated short term exposures increased the bactericidal effect of chlorhexidine but not that of iodine. The difference in antimicrobial effect between chlorhexidine and that of iodine on S. mutans and S. sanguis should be investigated in persons heavily infected by S. mutans .     

Effects of acidification on growth and glycolysis of Streptococcus sanguis and Streptococcus mutans

After carbohydrate intake, pH in dental plaque decreases rapidly and reaches about 4 within a few minutes. The acidification not only promotes demineralization of tooth surface but can also cause damage to bacteria in dental plaque. We, therefore, investigated the effect of acidification on the dental plaque bacteria Streptococcus sanguis and Streptococcus mutans. At pH 4.0 and 4.2, both growth and glycolytic activities in these streptococci were repressed. Prolonged acidification (for 60 min at pH 4.0) not only repressed both growth and glycolytic activities but also impaired them in S. sanguis cells with concomitant inactivation of the glycolytic enzymes, hexokinase, phosphofructokinase, glyceraldehyde-phosphate dehydrogenase and enolase. The impaired abilities of glycolysis and growth recovered following incubation at pH 7.0 for 80–90 min, and this was accompanied by reactivation of the glycolytic enzymes. On the other hand, these impairments were not observed in S. mutans cells exposed to prolonged acidification. These results indicate that the low pH frequently occurring in dental plaque may transiently impair streptococcal glycolysis and growth and that S. mutans is more durable to the acidification than S. sanguis.     

Compounds which affect the adherence of Streptococcus sanguis and Streptococcus mutans to hydroxyapatite.

Several compounds were evaluated in an in vitro assay system for their ability to block the adherence of Streptococcus sanguis to saliva-coated hydroxyapatite and Streptococcus mutans to dextran-coated hydroxyapatitite. Fatty acids, ranging from C-12 to C-20, the enzyme amylase, chlorhexidine, human sera, and several serum proteins blocked S sanguis adherence to saliva-coated hydroxyapatite. Chlorhexidine blocked S mutans adherence to dextran-coated hydroxyapatite, but human sera and serum proteins did not. The effects of these compounds on the adherence of these organisms to hydroxyapatite may help in the development of specific plaque control methods for use in human populations.     

Streptococcus mutans, not detected?

The growth of Streptococcus mutans was followed for three years in 24 healthy 12-17 year-old children, who were selected for the study on the basis of undetectable levels of salivary S. mutans. The saliva samples were cultured by a dip-slide method based on mitis-salivarius agar supplemented with sucrose and bacitracin. At the final occasion, additional examination of plaque and saliva of 10 children using TSY20B agar was performed. During the 3-year study period, S. mutans was found in saliva samples from 15 children on one or more of the 4 test occasions, suggesting that most 'S. mutans negative individuals' were those in whom S. mutans could not be temporarily detected. The additional examination of plaque did not increase the number of 'S. mutans-positive individuals'.     

Effects of highly concentrated stannous fluoride and chlorhexidine regimes on human dental plaque flora

The aim of this study was to determine the effect of an intensive antimicrobial treatment on the number of Streptococcus mutans, Streptococcus sanguis, Actinomyces viscosus/Actinomyces naeslundii, and the total Colony-forming Units (CFU) in plaque. The dentition of human volunteers was treated in a dental office with either chlorhexidine (5%) or stannous fluoride (8%). Following the office treatment with chlorhexidine, selected volunteers rinsed daily at home for seven or 49 days with chlorhexidine solution (0.2%), while another group flossed daily at home for seven days with dental floss impregnated with chlorhexidine. On days one, seven, 21, 35, and 49 after the local applications, we took saliva samples and plaque samples from fissures, smooth surfaces, and approximal areas. Chlorhexidine and stannous fluoride suppressed S. mutans and the Actinomyces species on all surfaces and in saliva. S. mutans on tooth surfaces was suppressed for approximately seven days and returned to the baseline level at day 21. A. viscosus/naeslundii was suppressed for more than seven days on the teeth. S. sanguis and the total CFU returned to the baseline level within seven days on all surfaces and in saliva. Rinsing or flossing with chlorhexidine suppressed S. mutans during the period of time that these supplements were used. Brushing for seven days with chlorhexidine gel (1%) without a preceding intensive chlorhexidine treatment had virtually no effect on S. mutans in approximal areas and in saliva, but suppressed S. mutans in fissures and on smooth surfaces.     

Susceptibility of Streptococcus mutans and Streptococcus sobrinus to antimicrobial agents after short-term oral chlorhexidine treatments

Effects of three different types of short-term applications (1–3 limes during 1 week) of chlorhexidine (1 or 40%) on the susceptibility of 863 clinical isolates of Streptococcus mutans and 53 isolates of Streptococcus sobrinus from 58 subjects were studied. Chlorhexidine-resistant isolates were not found either before or after the treatment. The minimum inhibitory concentrations (MICs) to chlorhexidine of all isolates of S. mutans were ≤1 μg/ml, and of S. sobrinus ≤2 μg/ ml. S. mutans and S. sobrinus were also susceptible to ampicillin, penicillin, cefuroxime, and tetracycline. In conclusion, different short-term chlorhexidine regimens do not induce resistance in S. mutans or S. sobrinus and, furthermore, these species have so far retained their susceptibility to common antibiotics.     

Effect of caries preventive measures on Streptococcus mutans and lactobacilli in selected mothers

Abstract – Mothers of first-born babies were selected on the basis of high salivary counts of Streptococcus mutans. All experimental subjects were given a basic caries preventive program in order to decrease the level of S. Mutans in saliva. the program included dietary counseling, which stressed the role of sucrose in the accumulation of S. Mutans. The treatment was carried out in a public dental office. The effect of the treatment was assessed by microbiological examination of salivary levels of S. mutars and lactobacilli. a stratistically significant reducation in both S. mutans and lactobacilli was found. The basic preventive program was effective in reducing the nuber of S. mutans below a selected threshold value of 3000000 CFU per mlsaliva in 60% of the mothers. In the remaining subjects chlorhexidine treatment was required to suppress the salivary levels of S. mutans below this value.     

Metabolism of 17B-estradiol by oral Streptococcus mutans, Streptococcus sanguis, Bacillus cereus and Candida albicans

The ability of oral isolates of Streptococcus mutans, Streptococcus sanguis, Bacillus cereus and Candida albicans to metabolize 17 beta-estradiol was analyzed by thin-layer chromatography using 4-14C-estradiol as the substrate. All test microorganisms metabolized 17 beta-estradiol. Estrone was the main metabolic product, except for B. cereus, which converted 17 beta-estradiol mainly to unidentified, more polar metabolites. S. sanguis and B. cereus had the most active metabolism but S. mutans and C. albicans were also active.     

噻唑蓝比色法检测变异链球菌、血链球菌、伴放线菌嗜血菌的研究

目的探讨噻唑蓝（MTT）法用于口腔常见细菌（变异链球菌、血链球菌、伴放线菌嗜血菌）活菌计数的可行性及具体应用过程中的实验条件。方法本实验以菌落形成单位（CFU）法为标准对照。实验通过改变比色的波长、反应时间、试剂剂量、细菌菌龄等实验条件,获得MTT法测量常见口腔细菌的一系列参数,对变异链球菌、血链球菌、伴放线菌嗜血菌进行活菌计数,并与CFU法所测的细菌数量相比较。结果MTT法在测量变异链球菌时,最佳的检测波长为510 nm,最佳的测定细菌范围是1.5×105～1.0×107 CFU·mL-1。MTT法在测量血链球菌时,最佳的检测波长为545 nm,最佳的测定细菌范围是1.5×105～2.0×107 CFU·mL-1。MTT法在测量伴放线菌嗜血菌时,最佳的检测波长为557 nm,最佳的测定细菌范围是1.0×106～5.0×107 CFU·mL-1。MTT法与菌落形成单位法的测量结果是一致的,并且对于不同菌龄的变异链球菌、血链球菌、伴放线菌嗜血菌均适用。结论MTT法可以用于检测变异链球菌、血链球菌、伴放线菌嗜血菌等口腔常见细菌的活菌数量,并且具有快速、方便等优点。     

Recolonization of human tooth surfaces by Streptococcus mutans after suppression by chlorhexidine treatment

In eight subjects who were initially highly colonized with Streptococcus mutans and who used a 1% chlorhexidine gel, the numbers of this organism were suppressed in both plaque and saliva. Bacterial plaque samples were obtained from all tooth surfaces, and the recolonization pattern of S. mutans was studied over a 26-week period. At baseline, 83% of all surfaces harbored S. mutans with buccal surfaces colonized in higher frequency than the others. After chlorhexidine treatment, the proportion of tooth surfaces colonized by S. mutans was reduced to a low level. Re-appearance was slow. S. mutans was first recovered from the most posterior teeth in the mouth, the molar surfaces were recolonized earlier than were those of pre-molars and anterior teeth, and the buccal surfaces were recolonized more readily than were the other tooth surfaces. The data show that there is a specific recolonization pattern of S. mutans after chlorhexidine treatment, and that the re-emergence of S. mutans is most probably due to regrowth of bacteria which have not been eradicated.     

Effect of the antibacterial agents octenidine and chlorhexidine on the plaque flora in primates

Abstract— The effect of the antibacterial substance octenidine on plaque formation and on oral microflora in eight monkeys fed a sucrose diet was studied. Plaque was obtained from buccal tooth surfaces of premolars and first molars in two quadrants using a swab and a dental carver and examined using culture and fluorescent antibody procedures. A significant reduction in plaque score was observed on the buccal tooth surfaces after daily topical application of 1% solutions of octenidine and chlorhexidine for 7 d; octenidine was more effective man chlorhexidine. Placebo treatment with water was without significant effect. Octenidine and chlorhexidine affected the plaque flora in a similar manner; the proportion of S. sanguis increased in relation to baseline levels while the population of Actinomyces, especially the group A. viscosus and A. naeslundii, was markedly reduced. S. sanguis showed an inverse relationship to members of Actinomyces in response to the action of the antimicrobial agents. Both plaque sampling methods revealed similar changes in bacterial composition as a result of treatment. The data show that octenidine is an effective inhibitor of dental plaque and its antimicrobial and antiplaque properties make it worthy of further studies.     

口腔环境因素对血型链球菌和变形链球菌生长的影响：II.氧的影响

口腔的链球菌族属于微需氧菌，易受到氧代谢产物的抑制作用，作者采用连续培养方法，观察血型链球菌（以下简称为血链菌）３４和变形链球菌（以下简称变链菌）Ｉｎｇｂｒｉｔｔ（ｃ）在有氧情况下的生长状态，得出血链菌３４的耐氧能力高于变链菌Ｉｎｇｂｒｉｔｔ（ｃ）的结果。这一结果与血链菌为牙菌斑的先锋定殖菌的现象相一致。而变链菌的耐氧能力差使其生长，以及致龋作用对牙菌斑的内环境有一定的依赖性。     

菌斑固相、变形链球菌及葡聚糖对酸的缓冲作用

目的研究糖代谢后菌斑固相缓冲力的变化及影响因素。方法采集40名18~21岁的大学生的饥饿牙菌斑,体外10%蔗糖孵育1h。体外制备无糖培养和2%蔗糖培养的变链菌团。以25mmol/L KCl制备菌斑固相、变链菌团和不溶性葡聚糖混悬液及可溶性葡聚糖溶液,用1mmol/LHCl滴定并计数细菌密度,统计学分析。结果变链菌团代谢蔗糖后的缓冲容量为(0·099±0·047)mmol/L,比无蔗糖培养的变链菌团的缓冲容量(0·609±0·202)mmol/L低,且缓冲力随细菌密度降低直线下降,葡聚糖几乎没有缓冲作用[(0·028~0·032)mmol/L]。人牙菌斑固相缓冲力的变化规律与体外纯菌培养研究结果一致。结论菌斑固相缓冲力与所含细菌密度密切相关。     

Antineoplastic agents inhibit the growth of Streptococcus mutans and Streptococcus sanguis in vitro

The effect of methotrexate (MTX) and doxorubicin on the growth, metabolism and ultrastructure of Streptococcus mutans and Streptococcus sanguis was studied in vitro. Both anticancer drugs exerted an inhibitory effect on the oral streptococci. MTX was more inhibitory than doxorubicin. The minimum inhibitory concentrations (MICs) of MTX to S. mutans were 0.25-2.5 micrograms/ml and that of doxorubicin 0.2 mg/ml. The MICs of MTX and doxorubicin to S. sanguis were 0.025 micrograms/ml and 2.0-0.02 mg/ml, respectively. When saliva samples of patients with malignant tumors receiving various doses of MTX were analyzed, MTX was found to be secreted into the oral cavity at concentrations ranging from 0.014 to 4.486 micrograms/ml. The saliva of these patients was also found to inhibit the growth of S. mutans, and the inhibition zones were in accordance with the MIC values observed. The results suggest that anticancer therapy must be taken into account when the salivary microbiological findings of cancer patients are interpreted.