Streptococcus gordonii's sequenced strain CH1 glucosyltransferase determines persistent but not initial colonization of teeth of rats.

OBJECTIVE: Extracellular glucan synthesis from sucrose by Streptococcus gordonii, a major dental plaque biofilm bacterium, is assumed important for colonization of teeth; but this hypothesis is un-tested in vivo. METHODS: To do so, we studied an isogenic glucosyltransferase (Gtf)-negative mutant (strain AMS12, gtfG(-)) of S. gordonii sequenced wild type (WT, strain Challis CH1, gtfG(+)), comparing their in vitro abilities to grow in the presence of glucose and sucrose and, in vivo, to colonize and persist on teeth and induce caries in rats. Weanling rats of two breeding colonies, TAN:SPFOM(OM)BR and TAN:SPFOM(OMASF)BR, eating high sucrose diet, were inoculated with either the WT (gtfG(+)), its isogenic gtfG(-) mutant, or reference strains of Streptococcus mutans. Control animals were not inoculated. RESULTS: In vitro, the gtfG(-) strain grew at least as rapidly in the presence of sucrose as its WT gtfG(+) progenitor, but formed soft colonies on sucrose agar, consistent with its lack of insoluble glucan synthesis. It also had a higher growth yield due apparently to its inability to channel carbon flow into extracellular glucan. In vivo, the gtfG(-) mutant initially colonized as did the WT but, unlike the WT, failed to persist on the teeth as shown over time. By comparison to three S. mutans strains, S. gordonii WT, despite its comparable ecological success on the teeth, was associated with only modest caries induction. Failure of the gtfG(-) mutant to persistently colonize was associated with slight diminution of caries scores by comparison with its gtfG(+) WT. CONCLUSIONS: Initial S. gordonii colonization does not depend on Gtf-G synthesis; rather, Gtf-G production determines S. gordonii's ability to persist on the teeth of sucrose-fed rats. S. gordonii appears weakly cariogenic by comparison with S. mutans reference strains.

Caries inhibition in rats by a remineralizing toothpaste.

We tested the anti-caries properties of a prototype remineralizing toothpaste containing sodium fluoride, soluble phosphate and soluble calcium, similar but not identical to Enamelon Toothpaste in specific pathogen-free Osborne-Mendel rats. A fluoride-free placebo and sodium fluoride-containing Crest Regular were used as negative and positive control toothpastes, respectively. Sixty weanling rats were randomly distributed into groups of 20, all were inoculated with S. mutans 10449S, ate diet 2000, and drank demineralized water. Each toothpaste, contained in coded tubes, was applied to the rats' teeth, once for one minute/day, five days/week. There was no difference in bacterial recoveries from tooth swabs among the groups at either the 22- or 37-day post-inoculation recovery date. After rat sacrifice and defleshing, heads were randomly coded and scored blindly for carious lesions according to Keyes/Larson methods. Only after scoring was completed were the random codes broken and the treatment groups identified. Both the Enamelon-like product and Crest Regular treatments resulted in lower total enamel caries scores than the placebo (p < 0.001). The sum of smooth surface scores was also lower for the fluoride-containing toothpastes than for the placebo (p < 0.001). However, the Enamelon-like product had greater caries inhibitory properties than Crest Regular on sulcal and approximal tooth surface categories (p = 0.004 and p = 0.045, respectively). Therefore, the Enamelon-like product had superior caries inhibiting properties compared to Crest Regular at these tooth areas.

Model for assessment of carious lesion remineralization, and remineralization by a novel toothpaste.

This study is of a novel toothpaste which induced remineralization of carious lesions in specific pathogen-free Osborne-Mendel rats. Randomly distributed weanlings in 7 groups (n = 10) each were initially induced to develop carious lesions as a result of a severe dietary and bacteriological challenge. Thus, all were inoculated with S. mutans 10449S, ate diet 2000CS (containing 56% cornstarch) ad libitum, and, upon weaning and for 10 additional days, drank demineralized water supplemented to 10% (w/v) with sucrose (SW) ad libitum. During these 10 days, 6 of the 7 groups of rats were topically treated with a slurried F(-)-free placebo toothpaste. On the 10th day after initial inoculation, two groups were sacrificed, one which had been treated with the placebo and the one which had been untreated. The remaining groups were then provided unsupplemented demineralized water (DW), fed diet 2000CS, and topically treated with either of 5 coded toothpastes: a slurry of the F(-)-free placebo, a similar slurry of a conventional sodium fluoride toothpaste (Crest Regular) containing about 383 ppm F-, or one of three prototype toothpastes formulated by Enamelon, Inc. containing soluble calcium and phosphate salts. Two of these contained 377 ppm F- after mixing their components, either as sodium monofluorophosphate (E-MFP) or as NaF (E-NaF). The third prototype contained 0 ppm F- (E-w/o F). Test items were applied to the dentition for one minute/day, five days/week. These 5 remaining groups were sacrificed 13 days after the DW provision. After defleshing, heads were coded randomly and scored blindly for carious lesions. The exchange of DW for SW was associated with highly significant reductions of 10449S recoveries (p < 0.001), but there were no differences in recoveries among the groups as a function of toothpaste type. Total mandibular and maxillary sulcal and smooth surface caries scores were statistically significantly lower for the E-NaF-treated group at 23 days than for the 23-day placebo-, E-w/o F(-)-, and conventional NaF toothpaste-treated group. Reductions were most impressive quantitatively on approximal tooth surfaces, where both the E-MFP and E-NaF groups had the lowest scores, but were also statistically significant at sulcal surfaces for the E-NaF group. Thus, this study model can be used to detect significant remineralization effects, as occurred with the prototype toothpaste E-NaF.

Coprolite assessment in nursing research and practice.

A reliable assessment of stools without the use of metabolic assays of stool content has not previously existed. The Wanger Stool Assessment Instrument (WSAI) was initially conceived as an efficacy outcome measure for a clinical investigation of enteral feedings. The WSAI is a descriptive tool that has three scales: a seven-category color scale, an ordinal scale that describes amount, and an ordinal scale that ranks consistency of stools. Instrument testing and development were conducted in stages. Nursing staff using the instrument reported that its use improved data collection as well as the patient information communicated among health care staff.

Fiber-fortified feedings in immobile patients.

The purpose of this pilot study was to test methods to measure the effects of a fiber-fortified, enteral feeding (Jevity) on the bowel habits of an immobile, tube-fed group of patients. Three experimental patients received fiber-fortified feedings for seven weeks, whereas four control patients received their usual enteral feeding. Measurements of the number of stools, the consistency of stools, the formula volume delivered, the daily water volume, the body temperature, the urinary output, and the bowel medications were made during three phases--a baseline, an adjustment, and a treatment period. Patients who receive the fiber-fortified enteral feedings had more stools and better consistency of stools than did those patients who did not receive the fiber-fortified formula. Results indicated that fiber-fortified feedings should be added gradually to immobile, tube-fed patients' diets under close supervision. Although measuring the effects of a new feeding in immobile, tube-fed patients is labor-intensive, it can be accomplished successfully.

Simultaneous caries induction and calculus formation in rats.

Weanling specific pathogen-free Osborne-Mendel rats were fed a high-calcium, high-phosphorus diet with various levels of sucrose and inoculated with Streptococcus sobrinus strain 6715-13WT and Actinomyces viscosus strain OMZ-105 in order to determine whether calculus and caries could develop simultaneously. Rats consumed diets designated RC-16-5, RC-16-25, or RC-16-50 which partially replaced the corn starch component with progressively higher levels of sucrose, thus, to 5, 25, or 50% sucrose. In general, bacterial recoveries of A. viscosus declined with higher sucrose content of the diet, but a pattern of recovery for S. sobrinus was less clear with respect to dietary sucrose. S. sobrinus, however, was recovered at higher percentages from the tooth surface flora at the later two of three sampling dates. Most calculus--identified by the brittle quality, staining characteristics, and apatitic x-ray diffraction patterns of tooth surface deposits--was formed on the maxillary molars, and most carious lesions occurred on mandibular molars. While there was minimal association of the calculus score with the amount of sucrose in the diet, calculus scores increased greatly from 23 to 43 days after infectious challenge. Caries scores, of both fissure and smooth surfaces, by contrast, increased in a dose-response fashion with increasing dietary sucrose and with time. It is thus possible to induce calculus formation and caries simultaneously in specific pathogen-free Osborne-Mendel rats consuming a high-calcium and -phosphorus diet conducive to calculus formation and containing sucrose.(ABSTRACT TRUNCATED AT 250 WORDS)