Effect of sodium nitrite and ascorbic acid on the growth and acid production of Streptococcus mutans

Nitrite at acid pH has been shown to be antibacterial particularly against the highly cariogenic species Streptococcus mutans. Nitrite might yield nitrosamines in vivo but ascorbic acid (vitamin C) could counteract these potential ill effects. The aim of this study is to determine whether ascorbic acid would interfere with the ability of sodium nitrite to suppress growth and acid production of S. mutans, NCTC 10449(T) and NCTC 10832. Strains were grown in Fastidious Anaerobe Broth before exposure to 200 mM nitrite in the presence of various concentrations of ascorbic acid (0.0, 5.7, 11.4, 17.0, 22.7, 28.4, 56.8, 85.2 mM). End pH was measured after 24 h exposure and cultures were serially diluted for viable counts. Statistical significance of differences in end pH values, each from 10 experiments, was determined using the Mann-Whitney U-Test. At all concentrations of ascorbic acid plus 200 mM nitrite plus S. mutans the pH was higher than with controls lacking ascorbic acid and/or nitrite (p>/=0.001). S. mutans was viable (between 4.5 x 10 (8) and 7.9 x 10 (9) cfuml (-1)) after growth in the presence of ascorbic acid at all concentrations without nitrite, whereas it was not detected when 200 mM nitrite was also present. CONCLUSIONS: ascorbic acid does not prevent the action of nitrite against S. mutans. Therefore ascorbic acid could be used in conjunction with nitrite to help counteract potential ill effects for humans.     

A 100 kDa vanadate and lanzoprazole-sensitive ATPase from Streptococcus mutans membrane

The cariogenic potential of Streptococcus mutans is due to the production of organic acids derived from energy metabolism, which implies the need of mechanisms for the organism to tolerate this acidic environment. The F₁F_o-ATPase is generally considered as the main enzyme responsible for cytoplasmic proton extrusion, but mutations that resulted in a 50% reduction in F₁F_o-ATPase activity in S. mutans still allowed the micro-organism to grow and extrude acid, keeping the intracellular pH one pH unit above the extracellular ambient. This finding suggests the existence of other enzymatic (or cellular) mechanisms that keep the cytosolic pH neutral during micro-organism growth.

This paper describes a membrane protein in S. mutans, with a molecular weight of 100 kDa, which exhibits ATPase activity inhibited by classic inhibitors of P-type ATPases (orthovanadate) and H⁺,K⁺-ATPase (lanzoprazole), has an optimum pH comparable to other H⁺-ATPases and undergoes phosphorylation during the catalytic reaction, like that of H⁺-ATPases described in yeast and plant plasma membrane. Together, these results strongly suggest that the enzyme we describe here is a P-type H⁺-ATPase or H⁺,ion-ATPase that can act in association with F₁F_o-ATPase during the growth of the S. mutans.     

一种噬菌体裂解酶的抗龋作用研究

目的: 探讨噬菌体裂解酶ClyR对变异链球菌(Streptococcus mutans,S. mutans)和远缘链球菌(Streptococcus sobrinus,S. sobrinus)临床株的杀菌作用。方法: 收集重度低龄儿童龋(severe early childhood caries,SECC)患者牙菌斑标本进行厌氧培养,通过菌落形态、生化鉴定、16S rDNA序列分析等方法对获得的临床株进行鉴定。通过细菌浊度A₆₀₀的降低和最低杀菌浓度(minimum bactericidal concentration,MBC)评价ClyR的杀菌效果。透射电镜(transmission electron microscopy,TEM)初步探究ClyR的杀菌作用机制。结果: 从分离得到的菌株中随机挑选10株S. mutans和10株S. sobrinus进行杀菌活性测试,50 mg/L ClyR对8株S. mutans有明显杀菌作用,其MBC范围为125 mg/L至 >1000 mg/L不等;对3株S. sobrinus有杀菌作用,其MBC范围为125~500 mg/L不等。TEM观察结果表明ClyR可在细菌细胞壁上打孔,从而使细菌发生渗透性死亡。结论: ClyR对S. mutans和S. sobrinus均有较强的杀菌作用,但对S. mutans杀菌作用较S. sobrinus强,或许可以作为一种防龋药物应用于临床。     

Changes in enamel surface roughness and adhesion of Streptococcus mutans to enamel after vital bleaching

Objectives. The purpose of this in vitro study was to observe the influence of vital bleaching on changes to the enamel surface and adhesion of Streptococcus mutans to tooth enamel.

Methods. The coronal part of each of 70 extracted third molars was cut in half, with either the buccal or lingual half used for experiments or controls. Experimental halves were assigned to the following conditions: (A) enamel was bleached 1, 3 or 5 times using a bleaching material with or without etching; or (B) etched condition without bleaching. All control samples were kept intact in physiological saline solution. Surface roughness (Ra; roughness center-line average: μm) of enamel was measured for 35 pairs of specimens. TS broth culture medium containing 3% glucose was inoculated with S. mutans and cultured for 72 h before adding the other 35 pairs of specimens. Under scanning electron microscopy, the number of S. mutans colonies was counted and statistically analysed.

Results. Compared to controls, bleached enamel displayed increased colonies of S. mutans. Repeated bleaching further increased bacterial adhesion and maximal colonies counts were found under conditions of five bleaching treatments plus etching (p≤0.01). Compared to controls, roughness increased after etching. However, no linear correlation was found between number of S. mutans colonies and roughness.

Conclusion. We conclude that both surface roughness and adhesion of S. mutans to the enamel surface increase after bleaching.     

针对变异链球菌的人源特异性靶向抗菌肽C16LL-37的生物学特性

目的 研究针对变异链球菌（S. mutans）的人源特异性靶向抗菌肽C16LL-37的生物学特性。方法 通过标准固相合成技术（Fmoc保护法）合成人源抗菌肽LL-37、S. mutans感受态刺激肽（CSP）C端16个氨基酸组成的多肽CSPC16及二者的重组多肽C16LL-37;以LL-37、CSPC16为对照组,采用平板菌落计数法检测C16LL-37对S. mutans、黏性放线菌、大肠埃希菌、嗜酸乳杆菌、金黄色葡萄球菌的抗菌活性及其对S. mutans的靶向性。通过扫描电子显微镜（SEM）观察,浓度为32 μmol·L-1的C16LL-37作用后S. mutans的细胞形态学变化;利用酶联免疫吸附法测定C16LL-37的红细胞溶血率以及不同条件对C16LL-37抗菌活性的影响。结果 1）C16LL-37对S. mutans的最小抗菌浓度为16 μmol·L^-1,最小杀菌浓度为64 μmol·L^-1。2）C16LL-37浓度为64 μmol·L^-1时,作用30 min后S. mutans存活率为3.46%,作用60 min后细菌存活率降至0%,其他4种细菌在各时间的存活率均大于60%（P<0.05）。3）SEM观察：经C16LL-37（32 μmol·L^-1）作用后,部分S. mutans细胞形态出现不规则改变,部分细胞的细胞膜粗糙、细胞质外溢或出现细胞裂解。4）C16LL-37浓度不超过64 μmol·L^-1时,红细胞溶血率低于0.33%,与阴性对照组无明显差异（P>0.05）。5）不同温度、pH值、盐浓度及低浓度胰蛋白酶处理后,C16LL-37的抗菌活性无明显变化（P>0.05）。结论 C16LL-37对变异链球菌具有靶向特异性,并且具有较强的抗菌活性、较高的生物安全性及良好的稳定性。     

变异链球菌双组分信号传导系统的研究进展

龋病是一种细菌感染性疾病,变异链球菌是主要致龋菌。变异链球菌的双组分信号传导系统由膜相关组氨酸蛋白激酶和胞内反式作用因子两个基本成分组成。双组分信号传导系统可以使变异链球菌感应外界环境变化和调节内部基因表达,这对于维持细菌的生存和毒力调整有重要作用。本文就与变异链球菌应激应答密切相关的双组分信号传导系统研究现状作一综述。     

Saliva mediated adherence, aggregation and prevalence in dental plaque of Streptococcus mutans, streptococcus sanguis and actinomyces spp. in young and elderly humans

Salivary components in the pellicle mediate bacterial adherence to the tooth. Such components may also aggregate bacteria in saliva and prevent them becoming established in dental plaque. In the present study, the adherence and aggregation of Streptococcus mutans strain Ingbritt, S. sanguis strain 10556 and Actinomyces viscosus strain 19246 mediated by parotid and whole saliva from groups of young and elderly people were examined. Significant differences were found between test strains, salivary secretions and age groups. S. sanguis 10556 and A. viscosus 19246 generally adhered more strongly than S. mutans Ingbritt, which adhered better to pellicles from parotid saliva than from whole saliva. Strain 19246 bound in higher numbers to parotid saliva pellicles from elderly compared to young individuals. Strain 10556 adhered better to whole saliva than parotid saliva pellicles, and the difference was significant among the young individuals, indicating reduced adherence ability in elderly whole saliva. The streptococci were aggregated by parotid and whole saliva, and S. sanguis aggregation was less with whole saliva from the elderly than from the young participants. Besides a correlation between whole saliva aggregation of S. mutans and proportions of bacteria in plaque, no correlations were found for the individual binding properties of saliva and prevalence of bacteria in vivo. However, the level of saliva-mediated adherence in vitro was in the following order: S. mutans < Actinomyces S. sanguis, which corresponded to their isolation frequency in plaque. These findings emphasize the importance of initial adherence to salivary receptors in bacterial colonization on teeth. Further studies are needed to reveal if individual patterns in the in vitro binding characteristics of saliva lead to variation of colonization in vivo.     

基于重水拉曼技术的白色念珠菌对变异链球菌代谢活性和耐药性影响的研究

目的 评价氟化钠(NaF)对变异链球菌的抑菌效能;白色念珠菌代谢产物对变异链球菌代谢活性和NaF作用下的耐药性影响.方法 分别采用肉汤稀释法和重水拉曼技术,参考最低抑菌浓度(MIC)及最小代谢活性抑制浓度(MIC-MA)指标,评价NaF对变异链球菌生长及代谢的抑制效果;采用重水拉曼技术,检测不同浓度白色念珠菌上清液对变...     

Ozone action on Streptococcus mutans and Lactobacillus fermentum: A pilot study

AIM: To study the effectiveness of ozone in the elimination of cariogenic bacteria, followed with fluoride supplements. METHODS: Sixty extracted teeth free of caries were used, and five groups were constituted. In Group I, the teeth were immersed in artificial saliva. In Group II, the teeth were inoculated with Streptococcus mutans (S. mutans) and immersed in artificial saliva. In Group III the teeth were inoculated with Lactobaccilus fermentum (L. fermentum) and immersed in artificial saliva. In Group IV the teeth were inoculated with S. mutans and L. fermentum and immersed in artificial saliva and the teeth in Group V were inoculated with S. mutans and L. fermentum, and were subjected to the application of ozone and to the action of a fluoride mineralizing gel. DIAGNOdent was used to evaluate the caries of the teeth 3 wk after inoculation of bacteria and after that the teeth of Group V were subjected to the application of ozone during 60 s, by HealOzone. After the application of ozone, products of the remineralization kit supplied by the manufacturer were applied daily, during 30 d. At the end samples were collected for analysis and evaluation of bacterial activity by polymerase chain reaction. RESULTS: Regarding the value of caries, obtained via DIAGNOdent, in the initial measurement the groups are homogeneous (P = 0.730). There was an increase in DIAGNOdent values, presenting statistical significant difference regarding the initial measurement in all groups (P ˂ 0.001), except in group I - only artificial saliva - which shows that the artificial carie model was effective. Comparing the initial and final measurements for each of the 60 teeth, it can be observed that in 9 teeth (15.0%) there was a decrease in values between the two measurements, one (1.7%) retained the same values in the two measurements and in the remaining 50 cases (83.3%) there was increase in values between the initial and final measurements. It should also be noted that in the teeth inoculated with S. mutans + L. fermentum, there was an increase of the values in 100% of cases, and in all groups except the group with artificial saliva, there is a more frequent increase in the values. In group V, subject to the application of ozone, bacterial DNA was not detected, in group IV, bacterial DNA was detected. CONCLUSION: Ozone was effective in the elimination of the study bacteria.     

Effects of mouthrinses with triclosan, zinc ions, copolymer, and sodium lauryl sulphate combined with fluoride on acid formation by dental plaque in vivo

Bacteriological tests demonstrated a slight synergistic effect of triclosan and sodium lauryl sulphate (SLS) on the growth of Streptococcus mutans NCTC 10449 and Streptococcus sanguis ATCC 10556 in vitro. A single mouthrinse with SLS (17.4 mM) or SLS plus triclosan (3.5 mM) significantly decreased the number of salivary mutans streptococci in a group of 12 subjects up to 90 min after rinsing. The effect on plaque pH of a mouthrinse with either 12.0 mM NaF, NaF plus 10.0 mM zinc acetate, NaF plus 17.4 mM SLS, or NaF plus SLS plus 3.5 mM triclosan with or without the addition of zinc ions or 0.65% w/v of a polyvinylmethyl ether/maleic acid copolymer was investigated. The plaque pH responses to a 10% w/v sucrose mouthrinse were measured in 2-day-old plaque with microtouch pH electrodes in six groups of 10 subjects 90 min after a single mouthrinse with test solution. There was no significant difference in plaque pH between the various mouthrinses. In conclusion, triclosan enhanced the growth-inhibitory activity of SLS against oral streptococci in vitro but not against salivary mutans streptococci in vivo. Neither triclosan incorporated into a mouthrinse containing SLS plus fluoride, nor the addition of zinc ions or copolymer affected acid formation by dental plaque in vivo.     

sortase A与变异链球菌致龋性关系的代谢组学研究

目的 探索srtA基因编码的转肽酶sortase A（SrtA）影响变异链球菌致龋性的机制。方法 采用基于¹H核磁共振波谱（NMR）的代谢组学方法,比较野生型变异链球菌UA159与srtA基因缺陷型变异链球菌UA159的胞外代谢产物;联合使用主成分分析和正交偏最小二乘法—判别分析鉴定不同菌株之间代谢产物的差异。结果 大多数有差异性的代谢产物是未知的,可识别的差异性代谢产物有亮氨酸和缬氨酸（δ 0.92×10^-6~1.20×10^-6）、乳酸（δ 1.28×10^-6）、酮戊二酸（δ 3.00×10^-6）、甘氨酸（δ 3.60×10^-6）。结论 在进一步完善微生物代谢产物数据库的基础上,¹H NMR代谢组学可用于龋病病因的研究。     

Antimicrobial effect of acidified nitrite on periodontal bacteria

The antimicrobial agent nitric oxide (NO) is formed in the mouth and its concentration is directly related to salivary nitrite, which in turn is related to dietary nitrate intake. The aim of this study was to determine whether nitrite under acidic conditions will have an inhibitory effect, possibly occurring through NO production, on the periodontal disease pathogens Fusobacterium nucleatum, Eikenella corrodens and Porphyromonas gingivalis. Whereas the growth of these organisms was inhibited by a more acid pH, the addition of nitrite caused a marked, further dose-dependent reduction in bacterial numbers after exposure. The ability of these bacteria to recover from nitrite exposure was also affected by pH and nitrite concentration. At acidity levels below pH 5.0, low concentrations of nitrite (0.2 mM) caused effective complete killing of the periodontal bacteria. Addition of sodium thiocyanate did not increase the bacteriostatic or bacteriocidal activity of acidified nitrite against any of the 3 bacteria. These results demonstrate the possibility that nitrite in saliva, under appropriate conditions, may have an effect on the growth and survival of the bacteria implicated in periodontal disease.     

Synergistic inhibition by combination of fluoride and xylitol on glycolysis by mutans streptococci and its biochemical mechanism

The purpose of this study was to evaluate the combined inhibitory effect of fluoride and xylitol on acid production by mutans streptococci, Streptococcus mutans NCTC10449 and Streptococcus sobrinus 6715, from glucose under strictly anaerobic conditions at fixed pH 5.5 and 7.0. The bacteria were grown in a tryptone-yeast extract broth under strictly anaerobic conditions (N2: 80%; H2: 10%; CO2: 10%). Reaction mixtures for acid production from glucose contained bacterial cells with fluoride (0-6.4 mM) and/or xylitol (60 mM). Acidic end products of glucose fermentation and intracellular glycolytic intermediates were assayed. The combination of fluoride and xylitol inhibited acid production more effectively than fluoride or xylitol alone. In the presence of fluoride and xylitol, the proportion of lactic acid in the total amount of acidic end products decreased, while the proportion of formic and acetic acids increased. Analyses of intracellular glycolytic intermediates revealed that xylitol inhibited the upper part of the glycolytic pathway, while fluoride inhibited the lower part. This study indicates that fluoride and xylitol together have synergistic inhibitory effects on the acid production of mutans streptococci and suggests that xylitol has the potential to enhance inhibitory effects of low concentrations of fluoride.     

Differences in pH fall, phosphorus content and dissolution of enamel in layers of the oral bacterium Streptococcus mutans deposited in vitro on bovine enamel granules with and without fluoride varnish

Bovine enamel granules were treated with fluoride varnish for 24 h. Samples of F-treated and untreated control enamel were covered with maleic-acid-NaOH buffer (pH 5.8) previously saturated with enamel salts and containing a standard amount of fresh Strep, mutons cells plus KCl and MgCl₂ (6 and 1 mM, respectively). The cells were centrifuged on the enamel; sucrose was added to the test and to control systems with fluoridated and non-fluoridated enamel; distilled water was added to non-fermenting controls. After incubation at 37 °C for intervals up to 2 h, fluoridation of the enamel had reduced the drop in pH of Strep, mutans plaque by 0.7 pH unit and reduced the release of Ca and P from enamel. Bacterial P levels were also significantly reduced in plaque in contact with fluoridated enamel. Magnesium concentrations outside the enamel were not altered.     

In-vivo dental plaque-forming ability and relative cariogenicity of the bacteria Streptococcus mitis and Streptococcus sanguis I and II in mono-infected gnotobiotic rats

Sixteen strains of Streptococcus mitis, Streptococcus sanguis I and Strep. sanguis II were tested for cariogenic potential and in-vivo plaque-forming ability in a gnotobiotic WAG/RIJ rat test system. All strains produced far less fissure plaque in vivo than strains of Streptococcus milleri or Streptococcus mutans. There was less extracellular matrix around cells of Strep. mitis or Strep. sanguis than around Strep. mutans, in the fissures. Dense sheets of cells were observed only with Strep. mutans. Some localized colonization of exposed smooth surfaces occurred with most strains. Strep, mitis produced no caries in three tests, low-caries scores in two tests and high-caries scores in one test. A single strain of Strep. mitis produced a highly-cariogenic variant able to ferment raffinose. Strep. sanguis I induced low-levels of caries in 12 tests; one test of NCTC 7865 produced moderate levels of caries, and another test of 311 produced no caries. Strep. sanguis 311 was dextran-negative. Strep. sanguis II strains induced no caries in three tests, low caries scores in six tests and moderate levels of caries with Strep. sanguis 402. No strain of Strep. mitis or Strep. sanguis was able to induce smooth-surface lesions.     

Microbial surface interactions: Reduction of the haemagglutination activity of the oral bacterium Fusobacterium nucleatum by absorption with Streptococcus and Bacteroides

Oral strains of Fusobacterium nucleatum showed haemagglutination (HA) of sheep red blood cells and attachment of HA-active F. nucleatum fragments to other microorganisms allowed a means of studying microbial surface interactions. HA-active sonicated fragments (SF) prepared from F. nucleatum were mixed with whole cell suspensions of 48 bacterial strains and, after incubation, the whole cells were separated from the non-absorbed fragments by differential centrifugation. Attachment of F. nucleatum fragments to the cells was indicated by a reduction in the HA activity of the SF in the supernatant fluid remaining after absorption with whole cells. HA activity of the microbial cells used for absorption and the detection of F. nucleatum fragments on these cells by an indirect fluorescent antibody technique provided further evidence of attachment. Of the 48 strains tested, 10 absorbed F. nucleatum HA-active fragments. They included Bacteroides gingivalis, Bacteroides fragilis subsp. distasonis, Bacteroides corrodens, Streptococcus morbillorum, Streptococcus sanguis (Blackburn and JC 74) and Streptococcus mutans AHT, BHT, 10449 and 6715. Chelators revealed that F. nucleatum attached to the microorganisms via a Ca^{2 +}-dependent interaction. Sugar inhibition demonstrated that F. nucleatum attached to the microorganisms via a D-galactose-containing moiety on their surface. A reduction in the absorption of F. nucleatum HA-active fragments by Strep. mutans grown in a higher concentration of sucrose was observed.     

Low-cariogenicity of trehalose as a substrate

Objectives: The effects of trehalose on cariogenesis by mutans streptococci were investigated.

Methods: Inhibited effect of trehalose on water-insoluble glucan (WIG) synthesis from sucrose by glucosyltransferase (GTase) of mutans streptococci was assayed. The acid fermentability of trehalose by mutans streptococci was determined by the measurements of pH, and amounts of lactic acid production. Plaque pH was determined by the measurements of collected plaque from volunteers after sugar mouth-rinse. Rat experimental caries was investigated by feeding a sucrose and/or trehalose diet.

Results: Trehalose was not utilized as a substrate for GTase. In addition, trehalose inhibited synthesis of WIG by GTase in the presence of sucrose. Trehalose showed weaker and slower acid fermentation than sucrose by mutans streptococci. The levels of lactic acid production from trehalose by Streptococcus mutans and Streptococcus sobrinus were 24.2 and 59.8% of those from sucrose, respectively. The minimum plaque pH after sucrose mouth-rinse was lower than those after trehalose mouth-rinse in all subjects. Plaque pH after trehalose mouth-rinse never reached critical pH. The substitution of trehalose for sucrose in the rat diet significantly reduced caries scores. Furthermore, rats fed diets containing sucrose and trehalose had significantly lower caries scores than those fed a sucrose diet.

Conclusions: These results suggested that trehalose might be not only lowly cariogenic but also anti-cariogenic, and is promising as a sugar substitute.     

The effect of sorbitol on the microbiology of the dental plaque in monkeys (Macaca irus)

A group of 4 monkeys was fed an essentially sucrose-free diet containing approximately 1 g/day sorbitol. The animals were infected with plaque from a cariesactive monkey and the population of Streptococcus mutans in plaque was determined over a period of weeks. A further group of 4 monkeys with an already established population of Strep. mutans in plaque was also fed a sorbitol-containing diet. The results obtained suggest that sorbitol will neither aid the implantation nor support the continuance of populations of Strep. mutans in plaque.

All eight monkeys were included in experiments to determine whether adaptive processes occurred in the plaque microflora during prolonged consumption of sorbitol. pH measurements were carried out using antimony micro-electrodes and the number of sorbitol-fermenting organisms in plaque monitored over a 2-yr period. The capacity of plaque to produce acid from sorbitol remained unaltered during the experimental period and no increase in the numbers of sorbitol-fermenting organisms was noted.

Large amounts of plaque were present in the sorbitol-fed monkeys but only one animal developed two small carious lesions after 3 yr consumption of a sorbitol-containing diet. Each of six control, sucrose-fed monkeys developed caries with multiple extensive lesions during the same period.

The results suggest that long-term consumption of sorbitol is unlikely to induce the formation of plaque capable of the rapid fermentation of sorbitol to low pH values.     

The effects of propanol, butanol, chlorhexidine, fluoride and combinations on the potassium and phosphate translocation and acid production by Streptococcus mutans

Non-growing cells of the K-1 strain of Streptococcus mutans, subjected to the influences of certain alcohols, chlorhexidine, fluoride or combinations of these factors, released varying amounts of both potassium and phosphate on incubation at pH 5.8. The combinations caused greater leakages of both potassium and phosphate than did each factor when used singly. Propanol enhanced the influence of both chlorhexidine and fluoride on the cellular potassium and phosphate content or accumulation.

After pretreatment with one or more of these substances, the cells were less able to produce acid during fermentation of sucrose, especially when propanol was used in the pretreatment.

The reduction of enamel solubility that was obtained through a pretreatment with sodium fluoride was not altered by propanol and chlorhexidine when used in the pretreatment together with the fluoride.     

Electron microscopic study of the interaction of oral microorganisms with polymorphonuclear leukocytes

A variety of Gram-positive plaque bacteria can trigger lysosomal enzyme release from rabbit polymorphonuclear leukocytes (PMNs) in vitro. This electron microscopic study was undertaken to assess the correlation between phagocytic activity by PMNs and lysosome release to Streptococcus mutons 6715, Streptococcus sanguis G9B, and Actinomyces viscosus T14. PMN phagocytic activity was quantitated by determining the percentage of cells showing evidence of phagocytosis (phagocytic index) and the number of bacteria within the PMNs (avidity index). High phagocytic activity was accompanied by vigorous PMN lysosomal enzyme release. On the other hand, when PMNs exhibited low phagocytic activity lysosomal enzyme release was minimal. For example, Streptococcus mutans grown in brain-heart infusion broth did not induce significant lysosome release or demonstrable phagocytic activity by PMNs. In contrast, Strep. mutans grown in BHI containing sucrose or pre-incubated with anti-Strep. mutans antibodies acted as potent triggers of lysosome release and PMN phagocytosis. Our results indicate that various species of oral Gram-positive bacteria trigger different responses from PMNs and that phagocytic activity of PMNs correlates well with the ability of these microorganisms to stimulate lysosomal enzyme release.