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.     

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 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 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.     

Antimicrobial susceptibility of 1042 strains of Streptococcus mutans and Streptococcus sobrinus: comparison from 1985 to 1989

A total of 1042 strains of Streptococcus mutans and Streptococcus sobrinus isolated between 1985 and 1989 were tested to study the evolution of their sensitivity to penicillin, amoxycillin, amoxycillin/clavulanic acid, cefuroxime, tetracycline, erythromycin, spiramycin, acetyl spiramycin, lincomycin and clindamycin. The strains were taken from stock cultures and isolated from human saliva and dental plaque. The minimal inhibitory concentration (MIC) was determined by an agar dilution method. Except for spiramycin and acetyl spiramycin, all the antibiotics inhibited 100% of the strains with concentrations less than or equal to 2 micrograms/ml. Microorganisms from both species underwent a slow progressive loss of sensitivity to all the antibiotics over a 5-year period of study, showing statistically significant results in most cases.     

Activity of amine-stannous fluoride combination and chlorhexidine against some aerobic and anaerobic oral bacteria

The in vitro susceptibility of 128 bacterial strains was tested to amine fluoride-stannous fluoride (AmF + SnF) and chlorhexidine (CHX) solutions. Actinobacillus actinomycetemcomitans, Streptococcus mutans, and Bacteroides intermedius were among the species investigated. The 50% and 90% minimal inhibitory concentrations (MICs) were assessed by an agar dilution method. The MIC ranges for A. actinomycetemcomitans were 2-32 micrograms/ml for CHX and 0.25-64 micrograms/ml for AmF + SnF. The respective values for S. mutans were 0.5-8 micrograms/ml (CHX) and 2-8 micrograms/ml (AmF + SnF); and 4-8 micrograms/ml (CHX) and 2-4 micrograms/ml (AmF + SnF) for B. intermedius. Streptococcus faecalis and Staphylococcus aureus were most resistant of the control strains (MIC 64 micrograms/ml to CHX and 32 micrograms/ml to AmF + SnF, respectively). Thus, both solutions tested exerted a definite inhibitory action on the dental plaque pathogens studied.     

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.     

The in vitro effects of cetyltrimethylammonium naproxenate on oral and pharyngeal microorganisms of various ecological niches

The purpose of this study was to determine the in vitro susceptibility to cetyltrimethylammonium naproxenate for various aerobic and anaerobic micro-organisms responsible for oral and pharyngeal diseases by assessing the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) or minimum fungicidal concentrations (MFCs) and by determining kill-times. The MICs of cetyltrimethylammonium naproxenate for 46 tested strains (25 reference strains and 21 clinical isolates) ranged from 8 to 500 micrograms/ml. The MIC was found to be 31.25 micrograms/ml for 36% of the reference strains. Even lower MIC values (15.63 micrograms/ml) were observed for some anaerobic strains, for Haemophilus influenzae and for Candida tropicalis. MIC and MBC values corresponded for the majority of strains tested while the MFC for C. tropicalis and C. albicans was much higher. Only 9.5% of the clinical isolates gave a MIC value of 31.25 micrograms/ml. Enterococcus faecalis, Streptococcus pyogenes and Staphylococcus aureus showed MIC at 62.5 micrograms/ml. The MIC and MBC values among the isolates were comparable, while the MFC value for the yeasts was greater. A concentration of 125 micrograms/ml of cetyltrimethylammonium naproxenate inhibited the growth of all bacteria, except Enterobacteriaceae and Pseudomonaceae, and yeasts. Cetyltrimethylammonium naproxenate shows very rapid kill-time for S. sanguis (0"), and rapid (15") for S. pyogenes, S. dysgalactiae and S. mutans and for Moraxella catarrhalis, while a longer kill-time was necessary for the other microbes tested.     

In vitro inhibitory effects of Polygonum cuspidatum on bacterial viability and virulence factors of Streptococcus mutans and Streptococcus sobrinus

OBJECTIVES: Polygonum cuspidatum has been used in Korean folk medicine to improve oral hygiene. This study was performed to evaluate the effects of methanol extract from root of P. cuspidatum (MEP) on bacterial viability and the virulence factors of Streptococcus mutans and Streptococcus sobrinus. METHODS: To test the effects of MEP on bacterial viability, we determined the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) against 20 bacterial strains, including S. mutans and S. sobrinus, using a micro-dilution assay. In case of S. mutans and S. sobrinus, the assays for time-kill and bacterial growth rate at sub-MIC concentrations were also performed. To determine effects of the extract on the virulence factors of S. mutans and S. sobrinus, the assays for sucrose-dependent adherence, water-insoluble glucan formation, glycolytic acid production, and acid tolerance were performed at sub-MIC levels. Phytochemical analysis for constituents of MEP was carried out. RESULTS: MEP showed a broad antibacterial range (MIC 0.5-4 mg/ml). The MBC was two to four times higher than the MIC. The time-kill curves showed S. mutans and S. sobrinus were significantly killed after 1h of incubation. At sub-MIC levels, doubling times of S. mutans and S. sobrinus dose-dependently increased up to 211% and 123%, respectively. At sub-MIC levels, MEP also showed inhibitory effects on the virulence factors of S. mutans and S. sobrinus in a dose-dependent fashion. Phytochemical analysis revealed the presence of alkaloids, sterol/terpenes, tannins, flavonoids, and carbohydrates. CONCLUSION: These data indicate that MEP has inhibitory effects on bacterial viability at higher concentrations (> or =MIC) and the virulence factors of S. mutans and S. sobrinus at sub-MIC concentrations, suggesting that it might be useful for the control of dental plaque formation and subsequent dental caries formation.     

Selective effects of histidine-rich polypeptides on the aggregation and viability of Streptococcus mutans and Streptococcus sanguis

Enriched preparations of histidine-rich polypeptides (HRPs) and isolated HRP pairs (1-2, 3-4 and 5-6) degrade in the presence of fresh autologous whole saliva to a series of low-molecular-weight cationic peptides (HRPs 6a-c and 7). Analysis of the HRPs during degradation indicates that: HRP 1 is not the parent molecule of the HRPs; the HRP pairs do not convert to each other in a cascade-like sequence in saliva; and the HRPs can be separated into 2 groups consisting of HRPs 1-2 and 3-7. Preparations containing HRPs 1-7, 1-2, and 3-7 were obtained by fractionation and separation on Bio-Rex 70, and tested for aggregating and antibacterial effects against Streptococcus mutans BHT, S. mutans GS-5 and Streptococcus sanguis G9B. HRPs 1-2 had significant aggregating effects on all 3 strains but the other HRPs had little to no agglutinating ability. The HRPs did not inhibit the growth of S. sanguis, and HRPs 1-2 enhanced its growth. No growth enhancement by the HRPs was observed for the 2 S. mutans strains. However, significant bacterial inhibition of the S. mutans strains was noted after incubation with HRPs 3-7. The data suggest that the dissimilar effects of HRPs 1-2 and 3-7 may be of importance in the colonization and growth of S. mutans and S. sanguis in vivo.     

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 .     

人唾液中变形链球菌的荧光定量PCR检测

目的探讨荧光定量PCR技术对人唾液中变形链球菌进行定量检测的可行性。方法从30名受试者唾液样本中提取DNA,荧光定量PCR Taqman探针法检测变形链球菌和总细菌含量。结果受试者唾液中变形链球菌的检出率为100%,含量为3.27×104~6.31×106拷贝数/mg。结论使用荧光定量PCR技术可对人唾液中变形链球菌进行快速、批量定量。     

Salivary mucin as related to oral Streptococcus mutans in elderly people

MG1 (MUC5b and MUC4) and MG2 (MUC7), predominant mucins in human whole saliva, provide lubrication and antimicrobial protection for oral tissues. This study examines potential relationships between Streptococcus mutans titers in the oral cavity and the following: mucin concentrations; unstimulated and stimulated whole saliva flow rates; decayed, missing, and filled tooth surfaces; and age of 24 elderly patients. S. mutans titers were determined using Denticult SM. Mucin concentrations were determined using Stains-all, sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Logistic regression was used to identify potential relationships between the above variables. S. mutans classification served as the dependent variable. The remaining variables were possible predictor variables. The best model for predicting S. mutans category contained log MG2 as a predictor variable for all of its parameter estimates. No other set of parameter estimates were statistically significant. These results suggest that elevated S. mutans titers are significantly associated with diminished concentrations of MG2 in unstimulated whole saliva, as quantified in mucin-dye binding units.     

Glucosyltransferase production by Streptococcus sanguis Challis and comparison with other oral streptococci

Glucosyltransferase (GTF) activity in batch cultures of Streptococcus sanguis strain Challis in defined medium was maximum at peak growth and declined rapidly on further incubation into stationary phase. Activity was present in spent culture medium and was associated with 2 polypeptides of approximate Mrs 170 kDa (90% of activity) and 155 kDa (about 10% of activity). Other S. sanguis strains produced similar antigenically-related polypeptides but with varying activities, and antibodies to the S. sanguis enzyme did not react with enzymes produced by other species of oral streptococci. Increasing the [Na+] reduced GTF production by S. sanguis strains Challis and NCTC 7865, and by Streptococcus sobrinus, but not by Streptococcus salivarius. Addition of Tween 80 to cultures caused a rapid inhibition of GTF synthesis by strain Challis, but not by strain NCTC 7865. Benzyl alcohol had a slower and less inhibitory effect on GTF production by strain Challis. Tween 80 generally inhibited to varying degrees GTF production by other oral streptococci through in S. sobrinus it was stimulated. The results suggest controls operating on GTF synthesis and secretion by different strains of oral streptococci appear to be diverse.     

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。     

套式PCR检测唾液中变形链球菌及远缘链球菌

目的 探索一种快速、简便地从人类唾液中同时检测变形链球菌和远缘链球菌的方法。方法 分别以变形链球菌gtfI和远缘链球菌gtfB基因设计两组成套引物，首先用套式PCR（二次PCR）检测变形链球菌和远缘链球菌标准株和临床株，然后用套式PCR直接从唾液中检测这两种细菌。结果 变链菌（血清型c,e,f)的标准株及临床株第1次PCR扩增产物为517bp，第2次扩增产物为468bp；远缘链球菌（血清型d,g)及道勒链球菌（血清型h)的标准株及临床株第1次PCR扩增产物为712bp，第2次扩增产物为663bp;其他异种菌均不能扩增出产物，因此该PCR检测具有高度的特异性。细菌纯培养物及唾液PCR检测的敏感性分别是：第1次PCR为10^5CFU，第2次PCR为10^3CFU。结论 套式PCR能快速在人类唾液中同时检测变形链球菌和远缘链球菌。该检测方法有望运用于临床检测，对揭示两种细菌与龋病发生关系的研究具有一定价值。     

茶多酚对口腔细菌致龋力影响的实验研究

目的：通过研究茶多酚对致龋菌生长，产酸及产胞外多糖的影响。探讨茶多酚是否能有效调节口腔菌群生态平衡，方法：测定茶多酚对三种主要致龋菌－变形链球菌，粘性放线菌和血链球菌的最低抑菌浓度（MIC），再测定低于MIC的4个浓度的茶多酚对三种细菌产酸及产生水溶性和水不溶性多糖能力的影响。结果：茶多配合酚对三种细菌的生长，产酸均有一定的抑制作用。茶多酚能够有效抑制变形链球菌产生水溶性葡聚糖，但对变形链球菌产生水溶性葡聚糖以及粘性放线菌和血链球菌合成胞外多糖无明显的抑制作用。结论：茶多酚能有效抑制变形;链球菌，粘性放射菌和血链球菌的生长，产酸及变形链球菌产生水不溶性葡聚糖。     

白屈菜提取物抑制变形链球菌的实验研究

目的:研究白屈菜提取物白屈菜碱和白屈菜红碱对变形链球菌的抑制作用,探讨其防龋机制。方法:用二倍稀释法将白屈菜碱和白屈菜红碱等倍稀释为不同的浓度,用纸片扩散法测定其对变形链球菌的抑制作用,并用液体培养基测定其最低抑菌浓度(MIC),0.16%氯已啶溶液作为阳性对照。采用Spearman相关检验进行两组样本之间的相关分析。结果:白屈菜红碱乙醇溶液出现抑菌圈,而白屈菜碱乙醇溶液的各个浓度则无抑菌圈;100mg/ml的白屈菜红碱抑菌圈(25.8mm)大于对照组氯已啶溶液的抑菌圈(19.4mm);白屈菜红碱溶液浓度与变形链球菌抑菌圈大小之间具有高度相关性(r=0.99,P<0.01)。白屈菜红碱的最低抑菌浓度为0.78mg/ml。结论:白屈菜提取物白屈菜红碱有明显的抗菌作用,提示其可能具有较强的防龋作用。     

蜂房粗提物对致龋菌影响的实验研究

目的 研究蜂房粗提物对致龋菌生长，产酸及产胞外多糖的影响。探讨蜂房粗提物是否能有效调节口腔菌群的生态平衡。方法 测定蜂房粗提物对3种口腔内变形链球菌，粘性放线菌和血链球菌的最低抑菌浓度（MIC）。再测定低于MIC的4个浓度的蜂房粗提物对上述3种细菌产酸及产生水溶性和水下溶性多糖能力的影响。结果 蜂房粗提物对3种细菌的生长，产酸均有一定的抑制作用。能够有效抑制变形链球菌和血链球菌产生水不溶性葡聚糖，但对糖性放线菌合成水不溶性葡聚糖无明显抑制作用。结论 蜂房粗提物能有效抑制变形链球菌，粘性放线菌和血链球菌的生长，产酸及变形链球菌和血链球菌产生水不溶性葡聚糖。