Intrafamilial distribution of mutans streptococci in Japanese families and possibility of father-to-child transmission

The purpose of this study was to investigate the intrafamilial distribution of mutans streptococci in Japanese families using chromosomal DNA fingerprinting with three endonucleases; EcoRI, HindIII and HaeIII. The analysis of 1,908 isolates cultured from the dental plaque of 76 subjects from 20 families (20 married couples and 36 of their children) resulted in the identification of 144 genotypes containing 114 strains of Streptococcus mutans (serotype c, 66.7%; e, 12.5%) and 30 strains of S. sobrinus (d, 13.2%; g, 7.6%). A mean of 1.89 genotypes (from one to four) was harbored in individual subjects, and a mean of 4.10 genotypes from two to seven was harbored in individual families. Among the 70 genotypes found in the children, 36 (51.4%) were in agreement with their mothers and 22 (31.4%) were in agreement with their fathers. The other genotypes (18.6%) did not correspond with the parents. Homologous strains between parents were found in only two couples. This result showed that fathers or others as well as mothers can be sources of transmission. Further, the serotype d, e and g strains showed significantly higher probabilities of transmission than serotype c.     

ABO segregation distortion in Visakhapatnam, India.

Distortions in mother-infant, mother-child and father-child segregation for the ABO system as well as in the sex of offspring are described in a sample from a maternity service and from families of Visakhapatnam, India. Some distortions follow the expected fetomaternal incompatibility depression, others the expected feto-maternal induction of tolerance, and some remain unexplained. A differential action of selective factors on male and female fetuses, infants and children was also found, but no hypothesis could be postulated to explain it. The mother-infant matrix was found to be different from the mother-child matrix probably due to the inclusion of the reproductive time only in the mother-infant matrix. Unexpectedly, father-child segregation distortions were also found.     

Development of species-specific primers for detection of Streptococcus mutans in mixed bacterial samples

Streptococcus mutans is the major microbial pathogen associated with dental caries in children. The objectives of this study were to design and evaluate species-specific primers for the identification of S. mutans. Validation of the best primer set, Sm479F/R, was performed using seven S. mutans reference strains, 48 ATCC non-S. mutans strains, 92 S. mutans clinical isolates, DNA samples of S. mutans-Streptococcus sobrinus or S. mutans-Streptococcus sanguinis, and mixed bacterial DNA of saliva samples from 33 18-month-old children. All of the S. mutans samples tested positive, and no PCR products were amplified from members of the other streptococci or nonstreptococci strains examined. The lowest detection level for PCR was 10(-2) ng of S. mutans DNA (c. 4.6 x 10(3) copies) in the test samples. The results of this study suggest that the Sm479F/R primer pair is highly specific and sensitive for identification of S. mutans in either purified or mixed DNA samples.     

Evaluation of (GTG)<Subscript>5</Subscript>-PCR for rapid identification of <Emphasis Type="Italic">Streptococcus mutans</Emphasis>

Repetitive sequence-based polymerase chain reaction (PCR) fingerprinting using the (GTG)(5) primer was applied for fast screening of bacterial strains isolated from dental plaque of early childhood caries (ECC)-affected children. A group of 29 Gram-positive bacteria was separated into a homogeneous cluster together with Streptococcus mutans reference strains and constituted an aberrant branch after the numerical analysis of (GTG)(5)-PCR fingerprints. Automated ribotyping with EcoRI restriction enzyme (RiboPrinter microbial characterization system) revealed high genetic heterogeneity among the tested group and proved to be a good tool for strain-typing purposes. Further characterization of the studied strains was achieved by extensive phenotyping and whole-cell protein fingerprinting and confirmed all the strains as S. mutans representatives. Obtained results showed rep-PCR fingerprinting with the (GTG)(5) primer to be a fast and reliable method for identification of S. mutans.     

基于粪便DNA的贺兰山岩羊亲权鉴定和婚配制研究

2017年7-8月和11-12月在贺兰山岩画风景区采集到369份岩羊新鲜粪便样本,用多态性较高的10个微卫星位点进行基因分型,共识别出282只岩羊个体。通过复合扩増和牙釉蛋白基因PCR法共鉴定出152只雄性,130只雌性。微卫星分析得到平均等位基因（Na）为10.1,平均观测杂合度（Ho）为0.7737,平均期望杂合度（He）为0.6512,平均多态信息（PIC）为0.6129。运用Cervus3.0软件进行亲权鉴定,并用Kingroup V2计算个体间的亲缘系数（r）,作为亲权鉴定的补充,共鉴定出父-母-子7对,父-子21对,母-子19对。根据亲缘关系对岩羊的婚配制进行推测分析,表明岩羊婚配制应属一雄多雌。     

Substantivity of zinc salts used as rinsing solutions and their effect on the inhibition of Streptococcus mutans

The antimicrobial efficacy of zinc (Zn) salts (sulfate and acetate) against Streptococcus mutans (S. mutans) present in the oral cavity was tested in this study. The substantivity of Zn salts was assessed by determining the concentration of Zn in whole, unstimulated saliva and by measuring the magnitude of suppression of salivary S. mutans, 2h after rinsing. The concentration of Zn was measured by atomic absorption spectrometry (AAS) with electrothermal atomization (ET AAS) in saliva sampled before (basal) and 24h after mouth rinsing with different concentrations of Zn (0.1%, 0.5% and 1%) administrated as sulfate and acetate. The estimation of Zn levels in samples collected 30, 60, 90 and 120 min after rinsing was carried out by AAS with flame atomization (FAAS). Immediately after rinsing, the concentration of Zn in saliva sharply increased with respect to the baseline values (0.055+/-0.017 mg/L), followed by a sustained decrease, probably due to clearance of salivary flow or swallowing during sampling. A significant reduction (>87%) in the total mean S. mutans counts was found 2h after rinsing either with sulfate or acetate solutions, as evidence of the high substantivity and effectiveness of the Zn salts tested. A statistically significant inverse relationship (p<0.001 and the Pearson correlation coefficients between -34% and -50%) was found between Zn levels and the respective pH values measured in the samples collected 60 and 120 min after rinsing, sustaining the theory of bacterial glycolysis inhibition.     

赤藓糖醇对主要致龋链球菌及耐氟菌株生长和产酸的影响

目的通过赤藓糖醇对变形链球菌、远缘链球菌及其耐氟菌株混合菌生长和产酸影响的体外研究,为赤藓糖醇防龋作用的机理提供制论依据。方法采用最小抑菌浓度递增法对变形链球菌（S.mutans ATCC 25175,S.m）、远缘链球菌（S.sobrinus 6715,S.s）进行氟化钠体外诱导耐氟菌株（S.m-FR、S.s-FR）,利用液体稀释法配制赤藓糖醇TSB液8个浓度,分别加入含有变形链球菌、远缘链球菌及其耐氟菌株的细菌混悬液48 h,用比浊法观察其对混合菌生长的影响,并用pH计测定培养前后上清液的△pH值。结果吸光度A值和△pH值实验前后与对照组相比最低浓度为12%时差异均有统计学意义（P〈0.05）,且随着浓度的升高A值和△pH值均下降。结论赤藓糖醇能抑制变形链球菌、远缘链球菌及耐氟菌株混合菌生长和产酸,并且随着浓度的升高抑制作用增强。     

Antibacterial characteristics of <Emphasis Type="Italic">Curcuma xanthorrhiza</Emphasis> extract on <Emphasis Type="Italic">Streptococcus mutans</Emphasis> biofilm

This study evaluated the antibacterial effects of a natural Curcuma xanthorrhiza extract (Xan) on a Streptococcus mutans biofilm by examining the bactericidal activity, inhibition of acidogenesis and morphological alteration. Xan was obtained from the roots of a medicinal plant in Indonesia, which has shown selective antibacterial effects on planktonic S. mutans. S. mutans biofilms were formed on slide glass over a 72 h period and treated with the following compounds for 5, 30, and 60 min: saline, 1% DMSO, 2 mg/ml chlorhexidine (CHX), and 0.1 mg/ml Xan. The Xan group exposed for 5 and 30 min showed significantly fewer colony forming units (CFU, 57.6 and 97.3%, respectively) than those exposed to 1% DMSO, the negative control group (P<0.05). These CFU were similar in number to those slides exposed to CHX, the positive control group. Xan showed similar bactericidal effect to that of CHX but the dose of Xan was one twentieth that of CHX. In addition, the biofilms treated with Xan and CHX maintained a neutral pH for 4 h, which indicates that Xan and CHX inhibit acid production. Scanning electron microscopy showed morphological changes in the cell wall and membrane of the Xan-treated biofilms; an uneven surface and a deformation in contour. Overall, natural Xan has strong bactericidal activity, inhibitory effects on acidogenesis, and alters the microstructure of S. mutans biofilm. In conclusion, Xan has potential in anti-S. mutans therapy for the prevention of dental caries.     

Unterschiede zwischen Mutter-kind- und Vater-Kind-Korrelationen im Hautleistensystem des Menschen

Zusammenfassung An einem Untersuchungsgut von 92 Familien mit insgesamt 518 Personen wurden für 36 quantitativ erfaßbare dermatoglyphische Merkmale die Korrelationen zwischen den Kindern und ihren beiden Elternteilen festgestellt. Die Korrelationskoeffizienten aus den Mutter-Kind-Vergleichen liegen im Durchschnitt signifikant höher als diejenigen aus den Vater-Kind-Vergleiche, während zwischen Mutter-Sohn und Mutter-Tochter sowie zwischen Vater-Sohn und Vater-Tochter keine wesentlichen Unterschiede bestehen (Tabelle 2). Da illegitime Kinder und intrauterine Umwelteinflüsse als Ursache der höheren Mutter-Kindals Vater-Kind-Ähnlichkeit unwahrscheinlich sind und auch kein Effekt der Geschlechtschromosomen angenommen werden kann, muß damit gerechnet werden, daß das im weiblichen Gameten reichlicher vorhandene Plasma Erbinformationen trägt. Es wurde deshalb die — freilich zunächst nur rein heuristische — Hypothese einer extrachromosomalen Vererbung beim Menschen aufgestellt.

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Differences between mother-child and father-child correlations of the dermatoglyphics in man

Summary Correlations between children and their parents in a sample of about 92 families, being a total of 528 persons, were computed on the basis of 36 quantitative dermatoglyphic features. The average correlation coefficient for the mother-child comparisons is significantly higher than that for the father-child comparisons, whereas there are no essential differences between mother-son and mother-daughter or between father-son and father-daughter correlations (Table 2). Illegitimacy and the intra-uterine environment cannot be regarded as probable causes for the higher similarity between mother and child than between father and child; nor can an effect of the sex chromosomes be assumed. For these reasons the possibility that the plasma — being more abundant in the female gamete — carries genetic information must be considered. Therefore the (heuristic) hypothesis that there is extrachromosomal inheritance in man was formed.

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Manuskriptabfassung nach einem Vortrag auf der Tagung der Arbeitsgemeinschaft anthropologisch-erbbiologischer Gutachter im Oktober 1972 in München und unter Berücksichtigung der dortigen Diskussionsbemerkungen.     

儿童口腔内变形链球菌、乳酸杆菌的检出情况分析

调查评估年龄<12岁儿童口腔内变形链球菌及乳酸杆菌的检出情况及其与龋病的相关性。100例纳入实验的受试者根据不同龋敏感程度分为无龋组(DMFS=0)50人,高龋组(DMFS≥6)50人,按照不同龋敏感度、不同部位采集样本,用乳酸杆菌选择性培养基Rogosa和变形链球菌选择性培养基MSB,将乳酸杆菌和变形链球菌分离,经形态学及生化鉴定。统计2种细菌在不同分组中的检出率及不同致龋菌病例数,研究二者的致龋相关性。乳酸杆菌在100例研究对象中乳酸杆菌在龋坏深层检出率最高76%与光滑面(40%)、窝沟(48%)及唾液(40%)检出率比较有统计学意义(P<0.05),而龋坏深层变形链球菌检出率46%与光滑面(84%)、窝沟(68%)及唾液(78%)检出率比较最低(P<0.05);高龋人群变形链球菌检出率88%,乳酸杆菌检出率为76%均较无龋组相应细菌检出率26%、28%差异有统计学意义(P<0.05)。变形链球菌和乳酸杆菌随着龋敏感度的增加,乳酸杆菌和变形链球菌检出率增高;在龋坏深层更适于乳酸杆菌生长,且其对变形链球菌有一定的抑制作用。     

Examine growth inhibition pattern and lactic acid production in Streptococcus mutans using different concentrations of xylitol produced from Candida tropicalis by fermentation

Twenty clinical isolates of Streptococcus sp. were isolated from six clinical samples of dental caries on MSFA. Amongst these isolates, five clinical isolates were identified as S treptococcus mutans on the basis of morphological, biochemical and 16S rDNA sequencing. The isolated strains of S. mutans were exposed to fermented and purified xylitol (0.25-15.0%) and tested for its anti-microbial effects against control medium (Brain Heart Infusion without xylitol) after 12 h. The plate assay was developed using bromocresol green as an indicator dye in order to study the relative growth inhibition pattern of clinical sample at different concentrations of an anti-microbial compound in a single petriplate. The morphology of S. mutans cells in brain heart infusion (BHI) medium containing xylitol resulted in a diffused cell wall as observed using gram staining technique. The minimum inhibitory concentration (MIC) is 0.25% for S. mutans obtained from different clinical samples. The MIC(50) and MIC(90) is 5.0% and 10.0% xylitol respectively of the selected S. mutans being designated as clinical isolate B (6). The zone of inhibition was 72 mm and lactic acid production was 0.010 g/l at 10% xylitol concentration in Brain Heart Infusion Broth.     

Nonspecific inherited risk factors for acute respiratory diseases in children living in the western part of the Baikal-Amur railway

Variation of 9 polymorphic loci was compared in 2 groups of children from Russian native and migrant population of Western area of Baikal-Amur Railway--those who suffered from acute respiratory diseases during first year of life and their parents, and normal children and their parents. Frequencies of genotypes 1-1 (HP locus). 00 (ABO locus), and pp (F locus) were significantly higher in normal children than in the affected ones. Heterozygosity observed in native parents of the diseased children was lower as compared with other groups. It was possible to distinguish two groups, according to the degree of genic similarity: the first one included healthy children and their parents from migrant and native population, the second one included all affected children and their parents. Significance of association between phenotypes at 3 loci (HP, ABO, P) and predisposition of the children to acute respiratory diseases were evaluated. A conclusion was made that in children of both migrant and native Russian parents similar combinations of anthropological traits and gene markers are the factors of their nonspecific resistance to acute respiratory diseases.     

Genome composition of asymmetric hybrids in relation to the phylogenetic distance between the parents. Nucleus-chloroplast interaction

Summary A series of fusion experiments were performed between protoplasts of a cytoplasmic albino mutant of tomato, Lycopersicon esculentum (ALRC), and gamma-irradiated protoplasts of L. hirsutum and the Solanum species S. commersonii, S. etuberosum and S. nigrum. These species were chosen for their different phylogenetic relationships to tomato. In all fusion combinations except from those between ALRC and S. nigrum, green calli were selected as putative fusion products and shoots regenerated from them. They were subsequently analyzed for their morphology, nuclear DNA composition and chloroplast DNA origin. The hybrids obtained between ALRC and L. hirsutum contained the chloroplasts of L. hirsutum and had the flower and leaf morphology of L. esculentum. After Southern blot analysis, using 13 restriction fragment length polymorphisms (RFLPs) randomly distributed over all chromosomes, all hybrids showed L. esculentum hybridization patterns. No chromosomes of L. hirsutum were found. These results indicate that these hybrids were true cybrids.The putative asymmetric hybrids, obtained with S. commersonii and S. etuberosum, showed phenotypic traits of both parents. After hybridization with species-specific repetitive nuclear DNA probes it was found that nuclear material of both parents was present in all plants. In the case of S. nigrum, which combination has the greatest phylogenetic distance between the fusion parents, no hybrid plants could be obtained. The chloroplast DNA of all hybrid plants was of the donor type suggesting that chloroplast transfer by asymmetric protoplast fusion can overcome problems associated with large phylogenetic distances between parental plants.     

10种杜鹃亚属植物种间杂交的可育性研究

为探索杜鹃花亚属内异种杂交的可育性及其规律,对杜鹃亚属有鳞大花亚组(subsect. Maddenia)、三花杜鹃亚组(subsect. Triflora)、亮鳞杜鹃亚组(subsect. Heliolepida)及腋花杜鹃亚组(subsect. Scabrifolia)等4亚组10个杜鹃花种类的22个杂交组合(其中18个数据完整组合)的可育性进行了研究。结果表明:(1)所涉及的杜鹃亚属不同亚组间及三花杜鹃亚组内杂交均较困难,在18个数据完整组合中高可育与可育组合比率明显偏低,不育比率高(55.6%)。(2)在10个不可育或败育组合中,不能坐果(Cab型)、不能结实(Sab型)和可结实而种子不能发芽(Sng型)的数量分布为6∶1∶3,其不亲和或败育发生的阶段可能涵盖了从前合子期到后合子期的整个阶段。(3)亲本一方为多倍体组合的可育率(41.6%),尤其是母本为多倍体时,比二倍体组合的可育率(50.0%)低且无高可育组合出现,部分印证了倍性是导致该亚属植物不同种类杂交不亲和、不育与育性下降的重要原因,但不是唯一原因,亚组间杂交的可育率(16.7%)明显低于亚组内(三花杜鹃亚组内,58.3%)。(4)与相应的母本自然授粉结果相比,杂交明显导致多数可育组合绿苗率比率和单位可育种子数量比率的大幅度下降,这是双亲遗传差异及多倍体亲本介入后所导致的杂交衰退hybrid weakness现象。(5)在多倍体作母本的情况下,杂交单向不育或非对称遗传渗透现象明显。     

A novel selective medium for isolation of Streptococcus mutans

The aim of this study was to improve the selective medium of Streptococcus mutans. A new selective medium, designated MS-MUTV, was prepared by adding 10 mg/l valinomycin to the MS-MUT medium previously described. The average recovery of S. mutans was 72.1%, and the growth of S. sobrinus and S. anginousus group was inhibited on MS-MUTV, but allowed on MS-MUT. One hundred and thirty-nine human saliva samples were examined and counted for S. mutans and non-S. mutans colonies. The recovery of S. mutans on MS-MUTV was similar to that on MS-MUT. Eighty-two and 7.9 percent of the saliva samples obtained S. mutans pure cultures, with no bacterial growth on MS-MUTV, respectively. The remaining 10.1% were contaminated with non-S. mutans, with low-level CFU. MS-MUTV is useful for the isolation of S. mutans alone from clinical samples in routine examinations.     

Immunochemical characteristics of Streptococcus mutans serotype h carbohydrate antigen

Serotype h carbohydrate antigen was prepared from cell walls of Streptococcus mutans strain MFe28 of monkey origin. The h antigen was extracted from the cell walls with 5% trichloracetic acid at 4 C, and purified by DEAE-Sephadex A-25 ion exchange chromatography followed by Sephacryl S-300 gel filtration. The purified antigen was composed of galactose (75%), glucose (16%), and rhamnose (3%). Although the antiserum against whole cells of S. mutans MFe28 gave a strong cross reaction with serotype d S. mutans, serotype h-specific antiserum could be obtained by adequate adsorption. The precipitin reactions and hapten inhibition test using serotype h-specific antiserum showed that galactose, glucose, and their derivative sugars were markedly potent inhibitors. It was concluded that the serotype h antigen is immunologically distinguishable from the known serotypes of S. mutans, although it is closely related to serotype d antigen of S. mutans.     

Antibacterial activity of sophoraflavanone G isolated from the roots of Sophora flavescens

This study investigated the antibacterial activities of sophoraflavanone G from Sophora flavescens in combination with two antimicrobial agents against oral bacteria. The combined effect of sophoraflavanone G and the antimicrobial agents was evaluated using the checkerboard method to obtain a fractional inhibitory concentration (FIC) index. The sophoraflavanone G+ampicillin (AM) combination was found to have a synergistic effect against S. mutans, S. sanguinis, S. sobrinus, S. gordonii, A. actinomycetemcomitans, F. nucleatum, P. intermedia, and P. gingivalis, whereas the sophoraflavanone G+gentamicin (GM) combination had a synergistic effect against S. sanguinis, S. criceti, S. anginosus, A. actinomycetemcomitans, F. nucleatum, P. intermedia, and P. gingivalis. Neither combination exhibited any antagonistic interactions (FIC index >4). In particular, the MICs/MBCs for all the bacteria were reduced to one-half - one-sixteenth as a result of the drug combinations. A synergistic interaction was also confirmed by time-kill studies for nine bacteria where the checkerboard suggested synergy. Thus, a strong bactericidal effect was exerted through the drug combinations, plus in vitro data suggested that sophoraflavanone G combined with other antibiotics may be microbiologically beneficial rather than antagonistic.     

Diversity of the human immunodeficiency virus type 1 (HIV-1) env sequence after vertical transmission in mother-child pairs infected with HIV-1 subtype A

Although several virologic and immunologic factors associated with an increased risk of perinatal human immunodeficiency virus type 1 (HIV-1) transmission have been described, the mechanism of mother-to-child transmission is still unclear. More specifically, the question of whether selective pressures influence the transmission remains unanswered. The aim of this study was to assess the genetic diversity of the transmitted virus after in utero transmission and after peripartum transmission and to compare the viral heterogeneity in the child with the viral heterogeneity in the mother. To allow a very accurate characterization of the viral heterogeneity in a single sample, limiting-dilution sequencing of a 1016-bp fragment of the env gene was performed. Thirteen children were tested, including 6 with in utero infections and 7 with peripartum infections. Samples were taken the day after birth and at the ages of 6 and 14 weeks. A homogeneous virus population was seen in six (46.2%) infants, of whom two were infected in utero and four were infected peripartum. A more heterogeneous virus population was detected in seven infants (53.8%), four infected in utero and three infected peripartum. The phylogenetic trees of the mother-child pairs presented a whole range of different tree topologies and showed infection of the child by one or more maternal variants. In conclusion, after HIV-1 transmission from mother to child a heterogeneous virus population was detected in approximately one-half of the children examined. Heterogeneous virus populations were found after peripartum infection as well as after in utero infection. Phylogenetic tree topologies argue against selection processes as the major mechanism driving mother-to-child transmission but support the hypothesis that virus variability is mainly driven by the inoculum level and/or exposure time.     

Anticariogenic activity of macelignan isolated from Myristica fragrans (nutmeg) against Streptococcus mutans

The occurrence of dental caries is mainly associated with oral pathogens, especially cariogenic Streptococcus mutans. Preliminary antibacterial screening revealed that the extract of Myristica fragrans, widely cultivated for the spice and flavor of foods, possessed strong inhibitory activity against S. mutans. The anticariogenic compound was successfully isolated from the methanol extract of M. fragrans by repeated silica gel chromatography, and its structure was identified as macelignan by instrumental analysis using 1D-NMR, 2D-NMR and EI-MS. The minimum inhibitory concentration (MIC) of macelignan against S. mutans was 3.9 microg/ml, which was much lower than those of other natural anticariogenic agents such as 15.6 microg/ml of sanguinarine, 250 microg/ml of eucalyptol, 500 microg/ml of menthol and thymol, and 1000 microg/ml of methyl salicylate. Macelignan also possessed preferential activity against other oral microorganisms such as Streptococcus sobrinus, Streptococcus salivarius, Streptococcus sanguis, Lactobacillus acidophilus and Lactobacillus casei in the MIC range of 2-31.3 microg/ml. In particular, the bactericidal test showed that macelignan, at a concentration of 20 microg/ml, completely inactivated S. mutans in 1 min. The specific activity and fast-effectiveness of macelignan against oral bacteria strongly suggest that it could be employed as a natural antibacterial agent in functional foods or oral care products.     

A lacticin 3147 enriched food ingredient reduces Streptococcus mutans isolated from the human oral cavity in saliva

AIMS: To isolate and characterise Streptococcus mutans from Irish saliva samples and to assess their sensitivity to a food-grade preparation of the lantibiotic, lacticin 3147, produced by Lactococcus lactis DPC3147. METHODS AND RESULTS: Saliva samples collected from children with varying oral health status were screened on Mitis Salivarius agar for the presence of pathogenic streptococci. Following selective plating, 16S rDNA sequencing and Pulsed Field Gel Electrophoresis (PFGE), 15 distinct strains of Strep. mutans were identified. These were grouped according to their relative sensitivity to lacticin 3147 which ranged from 0.78 to 6.25%; relative to a sensitive indicator strain, Lactococcus lactis ssp. lactis HP. Inhibition of indicator Strep. mutans strains from sensitive, intermediate and tolerant groupings were assessed in microtitre plate assays with increasing concentrations of lacticin 3147. The concentration of lacticin 3147 required to give 50% growth inhibition correlated with their relative sensitivities (as assayed by well diffusion methodology) and ranged from 1280 to 5120 AU ml(-1). Concentrated preparations of lacticin 3147 caused a rapid killing of Strep. mutans strains in broth. Moreover, in human saliva deliberately spiked with Strep. mutans, the pathogen was eliminated (initial inoculum of 10(5)) in the presence of 40,000 AU ml(-1) of lacticin 3147. Furthermore, a food-grade lacticin 3147 spray dried powder ingredient was assessed for the inhibition of Strep. mutans in human saliva, spiked with a strain of intermediate sensitivity, resulting in up to a 4-log reduction in counts after 20 min. CONCLUSION: A food grade preparation of lacticin 3147 was effective in the inhibition of oral Strep. mutans. SIGNIFICANCE AND IMPACT OF THE STUDY: The inhibition of oral streptococci by food grade preparations of lacticin 3147 may offer novel opportunities for the development of lacticin 3147 as an anti-cariogenic agent particularly in the area of functional foods for the improvement of oral health.