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Microflora cultivable from minocycline strips placed in persisting periodontal pockets.

OBJECTIVE: The microflora that develops on minocycline strips, used as an adjunct in non-surgical periodontal therapy was studied. DESIGN AND METHODS: Minocycline (1.4 mg in polycaprolactone vehicle) and control strips were applied into all residual pockets (PD > or = 5mm, > or =2 pockets/subject) of patients with chronic periodontitis 1 month after a course of non-surgical periodontal therapy. Strips were inserted and retained for 3 days, changed to new strips for 3 more days and then removed. Strips were recovered from 14 (eight test, six control) of the 34 participants at day 0 (strip inserted, left for 30 s, removed), days 3 and 6, for (i) anaerobic culture, (ii) coliforms culture, using MacConkey agar, (iii) yeast culture, using Sabouraud's dextrose agar. RESULTS: The mean anaerobic cfu/strip (x10(5); control/test) were 2/6, 24/2, 11/2 at days 0, 3 and 6, respectively (P > 0.05). The corresponding mean proportion of Gram-negative rods and fusiforms were 27%/21%, 27%/15% and 55%/8%. The proportions of Gram-negative rods on test strips by day 6 were significantly reduced (P < 0.05). A significantly increased prevalence of Streptococcus mitis biovar 1 was found on spent test strips (control versus test; 0% versus 38%, Fisher exact test, P = 0.01). Coliform prevalence at days 0, 3 and 6 on control/test strips were 0/13%, 50%/38% and 50%/13%. Yeasts were occasionally isolated. CONCLUSIONS: The findings indicated that the minocycline strips but not the control strip supported a microbial colonisation compatible with periodontal health by day 6.

Administration, Oral↗

Extracellular enzyme activities during slow sand filtration in a water recharge plant.

Activities of the extracellular enzymes beta-glucosidase and phosphatase and bacterial densities were investigated during the filtration process at several sites in a groundwater recharge plant at the Ruhr river (Hengsen recharge plant in Schwerte. Germany). Low numbers of microorganisms and low levels of activity in this type of habitat, compared to most surface waters, caused methodological problems when determining microbial activity. In this study, fluorigenic model substrates, which enable hydrolytic rates as low as 1 nmol (L x h)(-1) to be measured, were used to determine extracellular enzyme activities. Highest activities were determined in surface water (107 nmol (L x h)(-1) for beta-glucosidase and 252 nmol (L x h)(-1) for phosphatase). which decreased during the filtration process in the gravel prefilter and the main sand filter until the end of subsurface flow (1.6 nmol (L x h)(-1) and 6.8 nmol (L x h)(-1), respectively). Similarly, bacterial numbers decreased from 3.4 x 10(6) to 0.29 x 10(6) cells mL(-1). These data showed that microbial activity within the prefilter and the shallow layers of the sand filter had the greatest impact on water quality. In addition to its involvement in the continuous purification of surface water, the microbial community in the sand filter probably acts as a biological buffer against ephemeral increases in the loads of organic matter and nutrients in the recharge plant.

Colony Count, Microbial↗

Subgingival microbiota of renal transplant recipients.

Renal transplant patients undergoing immunosuppressive therapy may experience periodontal side-effects such as gingival overgrowth. This study evaluated the subgingival microbiota of renal transplant recipients with or without periodontal tissue destruction who may have concurrent gingival enlargement. Subgingival paper point samples taken from the deepest probing sites of 38 subjects (one per patient) were examined using direct microscopy and culture techniques. A complex microflora comprising gram-positive and gram-negative cocci, rods and filaments, fusiforms, curved rods and spirochetes was observed using microscopy. Yeasts were occasionally detected. Significantly higher proportions of gram-positive morphotypes, including gram-positive cocci, were observed in samples from periodontally healthy patients. The predominant cultivable microflora from anaerobic culture comprised several species of facultative and obligate anaerobes. Colonization of the subgingival sites by 'foreign' microbes that are normally dermal, intestinal or vaginal flora was detected in up to 50% of the samples. High mean proportions of lost or unidentified species were also occasionally noted. The results showed that the subgingival biofilm of renal transplant recipients with chronic periodontitis comprised mainly gram-negative rods and spirochetes. Besides the usual predominant cultivable subgingival microbiota associated with periodontitis, the high prevalence of unidentified and 'foreign' microbes indicates the possibility of subgingival microbial alteration in renal transplant patients.

Adult↗

SAR11 clade dominates ocean surface bacterioplankton communities.

The most abundant class of bacterial ribosomal RNA genes detected in seawater DNA by gene cloning belongs to SAR11-an alpha-proteobacterial clade. Other than indications of their prevalence in seawater, little is known about these organisms. Here we report quantitative measurements of the cellular abundance of the SAR11 clade in northwestern Sargasso Sea waters to 3,000 m and in Oregon coastal surface waters. On average, the SAR11 clade accounts for a third of the cells present in surface waters and nearly a fifth of the cells present in the mesopelagic zone. In some regions, members of the SAR11 clade represent as much as 50% of the total surface microbial community and 25% of the subeuphotic microbial community. By extrapolation, we estimate that globally there are 2.4 x 10(28) SAR11 cells in the oceans, half of which are located in the euphotic zone. Although the biogeochemical role of the SAR11 clade remains uncertain, these data support the conclusion that this microbial group is among the most successful organisms on Earth.

Alphaproteobacteria↗

Innate secretory antibodies protect against natural Salmonella typhimurium infection.

The production of IgA is induced in an antigen-unspecific manner by commensal flora. These secretory antibodies (SAbs) may bind multiple antigens and are thought to eliminate commensal bacteria and self-antigens to avoid systemic recognition. In this study, we addressed the role of "innate" SAbs, i.e., those that are continuously produced in normal individuals, in protection against infection of the gastrointestinal tract. We used polymeric immunoglobulin receptor (pIgR-/-) knock-out mice, which are unable to bind and actively transport dimeric IgA and pentameric IgM to the mucosae, and examined the role of innate SAbs in protection against the invasive pathogen Salmonella typhimurium. In vitro experiments suggested that innate IgA in pIgR-/- serum bound S. typhimurium in a cross-reactive manner which inhibited epithelial cell invasion. Using a "natural" infection model, we demonstrated that pIgR-/- mice are profoundly sensitive to infection with S. typhimurium via the fecal-oral route and, moreover, shed more bacteria that readily infected other animals. These results imply an important evolutionary role for innate SAbs in protecting both the individual and the herd against infections, and suggest that the major role of SAbs may be to prevent the spread of microbial pathogens throughout the population, rather than protection of local mucosal surfaces.

Animals↗

Selection of a moxifloxacin dose that suppresses drug resistance in Mycobacterium tuberculosis, by use of an in vitro pharmacodynamic infection model and mathematical modeling.

BACKGROUND: Moxifloxacin is a quinolone antimicrobial that has potent activity against Mycobacterium tuberculosis. To optimize moxifloxacin dose and dose regimen, pharmacodynamic antibiotic-exposure targets associated with maximal microbial kill and complete suppression of drug resistance in M. tuberculosis must be identified. METHODS: We used a novel in vitro pharmacodynamic infection model of tuberculosis in which we exposed M. tuberculosis to moxifloxacin with a pharmacokinetic half-life of decline similar to that encountered in humans. Data obtained from this model were mathematically modeled, and the drug-exposure breakpoint associated with the suppression of drug resistance was determined. Monte-Carlo simulations were performed to determine the probability that 10,000 clinical patients taking different doses of moxifloxacin would achieve or exceed the drug-exposure breakpoint needed to suppress resistance to moxifloxacin in M. tuberculosis. RESULTS: The ratio of the moxifloxacin-free (non-protein-bound) area under the concentration-time curve from 0 to 24 h to the minimum inhibitory concentration associated with complete suppression of the drug-resistant mutant population was 53. For patients taking moxifloxacin doses of 400, 600, or 800 mg/day, the calculated target-attainment rates to suppress drug resistance were 59%, 86%, and 93%, respectively. CONCLUSION: A moxifloxacin dose of 800 mg/day is likely to achieve excellent M. tuberculosis microbial kill and to suppress drug resistance. However, tolerability of this higher dose is still unknown.

Antitubercular Agents↗

Enumeration of selected anaerobic bacterial groups in cecal and colonic contents of growing-finishing pigs.

Selected anaerobic bacterial groups in cecal and colonic contents of clinically healthy pigs fed a corn-soybean meal production diet were determined at sacrifice after 4, 8, and 11 weeks on feed, corresponding to intervals within the growing-finishing growth period. By using ruminal fluid-based media, the densities of the culturable anaerobic population; the cellulolytic, pectin-fermenting, pectin-hydrolyzing, xylan-fermenting; and the xylan-hydrolyzing, sulfate-reducing, and methanogenic bacterial populations were estimated. An analysis of variance was performed on these bacterial group variables to examine the effects of phase (weeks on feed), site (cecum or colon), or the interaction of phase with site. The population of total anaerobic bacteria was twice as dense in the colon as it was in the cecum (2 x 10(10) versus 1 x 10(10)/g [wet weight]; P = 0.001). The proportion of cellulolytic bacteria was lower at 4 weeks on feed than at 8 or 11 weeks (23 versus 32%; P = 0.026), while the proportion of pectin-fermenting bacteria depended on the interaction of phase with site (P = 0.021). The numbers of sulfate-reducing bacteria were significantly higher in the colon than in the cecum (6 x 10(7) versus 3 x 10(7); P = 0.014), as were methanogenic bacteria (19 x 10(7) versus 0.6 x 10(7); P = 0.0002). The remaining bacterial groups were stable with respect to phase and site. The results suggest that except for density differences, the microbial communities of the pig cecum and colon are similar in composition throughout the growing-finishing phase.

Analysis of Variance↗

Incidence and diversity of microorganisms within the walls of an active deep-sea sulfide chimney.

A large, intact sulfide chimney, designated Finn, was recovered from the Mothra Vent Field on the Juan de Fuca Ridge in 1998. Finn was venting 302 degrees C fluids on the seafloor and contained complex mineralogical zones surrounding a large open central conduit. Examination of microorganisms within these zones, followed by community analysis with oligonucleotide probes, showed that there were variations in the abundance and diversity of eubacteria and archaea from the exterior to the interior of the chimney. The microbial abundance based upon epifluorescence microscopy and quantitative fatty acid analyses varied from >10(8) cells/g of sulfide 2 to 10 cm within the chimney wall to <10(5) cells/g in interior zones. Direct microscopic observation indicated that microorganisms were attached to mineral surfaces throughout the structure. Whole-cell hybridization results revealed that there was a transition from a mixed community of eubacteria and archaea near the cool exterior of the chimney to primarily archaea near the warm interior. Archaeal diversity was examined in three zones of Finn by cloning and sequencing of the 16S rRNA gene. The majority of sequences from the exterior of the chimney were related to marine group I of the Crenarchaeota and uncultured Euryarchaeota from benthic marine environments. In contrast, clone libraries from interior regions of the chimney contained sequences closely related to methanogens, Thermococcales, and Archaeoglobales, in addition to uncultured crenarchaeal phylotypes obtained from deep subsurface sites. These observations of microbial communities within an active hydrothermal chimney provide insight into the microbial ecology within such structures and may facilitate follow-up exploration into expanding the known upper temperature limits of life.

Archaea↗

The effect of long-term use of a dentifrice containing zinc citrate and a non-ionic agent on the oral flora.

The effect on the oral ecology of daily use, for seven months, of a dentifrice containing 0.5% (w/w) zinc citrate and a non-ionic agent, i.e., 0.2% (w/w) Triclosan (2,4,4'-trichloro-2'-hydroxydiphenyl ether), has been monitored on 13 adult volunteers. Plaque and saliva were sampled monthly and the bacterial flora analyzed. Twenty-six volunteers used a placebo dentifrice as part of their normal oral hygiene for four months to establish the baseline microbial flora. The volunteers were then split into two equal groups: One group continued to use the placebo dentifrice; the other used the dentifrice containing zinc citrate and Triclosan. There was no evidence that seven months' use of a dentifrice containing 0.5% zinc citrate and 0.2% Triclosan caused shifts in the oral microbial ecology, nor was there any evidence of developing bacterial resistance to Triclosan.

Adult↗

Infection control properties of some wound dressings.

The ability of some wound dressings to sequester and retain micro-organisms associated with wound fluid is perceived to provide beneficial properties regarding infection control. This study used an in vitro model to investigate and compare such properties in a range of fibrous absorbent dressings (alginate, hydrofibre and hydrophobic). Dressings were challenged with a simulated wound fluid containing common wound pathogens (Staphylococcus aureus or Pseudomonas aeruginosa). Bacterial sequestering and binding levels were monitored over time. A hydrofibre dressing and two calcium alginate dressings were shown to effectively sequester challenge organisms from a simulated wound fluid. However, the hydrophobic and hydrofibre dressings produced statistically significant results in their ability to adsorb and retain challenge organisms (p < 0.05). These investigations have demonstrated that a hydrofibre dressing effectively sequesters and retains micro-organisms upon exposure to simulated wound fluid, and may therefore provide a passive mechanism for reducing the microbial load in wounds and in the surrounding environment. Further in vivo studies are required to investigate these dressing properties.

Alginates↗

The prevalence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Bacteroides forsythus in humans 1 year after 4 randomized treatment modalities.

The relationship between probing attachment changes in treated periodontal pockets and the prevalence of selected periodontal pathogens was assessed in 10 patients with adult periodontitis 1 year following randomized therapy. All patients had at least 1 tooth in each quadrant with an inflamed pocket of probing depth > or =5 mm and clinical attachment loss and harbored at least one of the following 3 major periodontal pathogens: Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, or Bacteroides forsythus. The number of target organisms per site was determined preoperatively; at 1 week; and at 1, 3, 6, and 12 months postoperatively utilizing DNA probes. The following clinical parameters were measured and recorded preoperatively and at 1, 3, 6, and 12 months post-treatment: gingival fluid flow, gingival index, plaque index, probing depth, probing attachment level, gingival recession, and bleeding on probing. One quadrant in each patient was randomly assigned to 1 of the following 4 treatments: 1) scaling and root planing; 2) pocket reduction through osseous surgery and apically-positioned flap; 3) modified Widman flap; and 4) modified Widman flap and topical application of saturated citric acid at pH 1 for 3 minutes. All 4 treatments were rendered in one appointment using local anesthesia. No postoperative antibiotics were used, but patients rinsed with 0.12% chlorhexidine for the first 3 months postoperatively and received a prophylaxis every 3 months. This investigation revealed: 1) 30.0% of the sites were infected by at least 1 species at 3, 6, and 12 months postoperatively. 2) Failing sites were infected by a high number of both Pg and Bf These sites had a mean of 24.2+/-9.0 x 10(3) Pg and 93.1+/-42.0 X 10(3) Bf while stable sites had a mean of 6.8+/-0.5 x 10(3) Pg and 7.2+/-1.2 x 10(3) Bf (P = 0.06 and P = 0.05, respectively). 3) The infected sites lost significantly more mean clinical attachment at 12 months (1.5+/-0.5 mm compared to a loss of 0.2+/-0.3 mm for uninfected sites, P = 0.017). 4) The infected sites had a significantly greater BOP (67+/-14% versus 25+/-8% for uninfected sites at 12 months, P = 0.012). 5) The choice of treatment modality did not affect the prevalence of the target species at 1 year post-treatment. These results suggest that prevalence of microbial pathogens negatively affects the 1 year outcome of periodontal surgical and nonsurgical therapy.

Adult↗

Periodontitis-associated marker bacteria in an urban North American patient population: application of a commercial immunoassay.

We used an immunoassay to demonstrate marker organisms (Porphyromonas gingivalis, Prevotella intermedia, and Actinobacillus actinomycetemcomitans) in 3 private practice populations (F-ME periodontist, 55 patients; MHM periodontist, 179 patients; and EWM general dentist, 19 patients). Occurrence of the marker organisms involves the whole oral environment, not just individual sites, as shown by close correlation between presence of the marker organisms in 2 independent sites/samples within a single mouth. Presence of the marker P. gingivalis (and P. intermedia) relates closely to periodontal pocketing while presence of A. actinomycetemcomitans does not have this pocket-associated characteristic. There was no significant relationship between presence of the marker organisms and the number of teeth in a mouth, and in the periodontal practice patients there was no significant effect of gender on occurrence of the marker organisms. A. actinomycetemcomitans and the other 2 markers were found over the entire age range (12 to 75) of our patients. Regular periodontal treatment reduced occurrence of all marker organisms and increased the frequency of marker-negative patients and sites. Occurrence of the marker organisms above immunoassay threshold levels appears to represent how receptive a patient is to each individual organism. Most patients appear receptive to the presence of P. intermedia whether treated or not. Significantly fewer patients who underwent regular treatment show the presence of P. gingivalis or A. actinomycetemcomitans when compared to untreated patients. Diagnostic application of microbial markers requires ongoing clinical assessment of patients and careful clinical judgment. 1391.

Adolescent↗

Effect of different mouthrinses on morning breath.

BACKGROUND: Morning breath odor is an often-encountered complaint. This double-blind, crossover, randomized study aimed to examine the bad breath-inhibiting effect of 3 commercially available mouthrinses on morning halitosis during an experimental period of 12 days without mechanical plaque control. METHODS: Twelve medical students with a healthy periodontium refrained from all means of mechanical plaque control during 3 experimental periods of 12 days (with intervening washout periods of at least 3 weeks). A professional oral cleaning preceded each period. During each experimental period, as the only oral hygiene measure allowed, the students rinsed twice a day with one of the following formulations in a randomized order: CHX-Alc (a 0.2% chlorhexidine [CHX] solution); CHX-NaF (CHX 0.12% plus sodium fluoride 0.05%); or CHX-CPC-Zn (CHX 0.05% plus cetylpyridinium chloride 0.05% plus zinc lactate 0.14%). After 12 days, morning breath was scored via volatile sulfur compound (VSC) level measurements of the mouth air and organoleptic ratings of the mouth air, the expired air, and a scraping of the tongue coating. At the 12-day visit, a questionnaire (subjective ratings) was completed and samples taken from both the tongue coating and the saliva for anaerobic and aerobic culturing and vitality staining. The de novo supragingival plaque formation was also recorded. All parameters were correlated with the baseline registrations. RESULTS: Although oral hygiene during the 3 experimental periods was limited to oral rinses, bad breath parameters systematically improved, with the exception of a slight increase in VSC levels while using CHX-Alc, a finding which was associated with the direct influence of the CHX on the sulfide monitor. The oral microbial load after the use of CHX-NaF remained unchanged, while for the CHX-Alc and CHX-CPC-Zn, significant reductions in both aerobic and anaerobic colony forming units (CFU)/ml were noticed in comparison with baseline data for both tongue coating and saliva samples. The composition of microflora, on the other hand, did not reveal significant changes. The supragingival plaque formation was inhibited, in descending order, by CHX-Alc, CHX-CPC-Zn, and CHX-NaF. The subjective scores for the rinses indicated a higher appreciation for CHX-CPC-Alc and CHX-NaF because of a better taste and fewer side effects. CONCLUSIONS: The results of this study demonstrate that morning halitosis can be successfully reduced via daily use of mouthrinses. CHX-Alc and CHX-CPC-Zn mouthrinses result in a significant reduction of the microbial load of tongue and saliva.

Adult↗

A survey of the microbial population and ethanol content of bagged salad.

Five nationally and regionally distributed brands of ready-to-eat salads in sealed bags were sampled from major supermarket chains. At time of purchase, product temperature was 4 to 7 degrees C; the mean mesophilic microbial population was 1.0 x 10(7) CFU/g; the yeast population was 210 CFU/g; the mean headspace O2 and CO2 concentrations were 1.2 and 12%, respectively; and the ethanol content was 700 ppm. For samples analyzed on the expiration date (14 to 16 days after packaging) the mean mesophilic microbial population was 6 x 10(7) CFU/g; ethanol content was 1,500 ppm; and the headspace gas had not markedly changed from time of purchase.

Bacteria↗

Microbial stability of mango (Mangifera indica L.) juice preserved by combined application of mild heat and extracts of two tropical spices.

The microbial stability of mango (Mangifera indica L.) juice (pH 4.9) supplemented with extracts of ginger (Zingiber officinale) and nutmeg (Myristica fragrans) was investigated during 3 months of ambient-temperature storage. Heating at 55 degrees C for 15 min markedly reduced the levels of non-spore-forming bacteria and produced a product with acceptable taste. Supplementing mango juice with an agueous extract of ginger (15%, vol/vol) or nutmeg (20%, vol/vol) inhibited the growth of challenge microorganisms, but produced a product with unacceptable taste. Heating the mango juice at 55 degrees C for 15 min and supplementing with nutmeg (4%, vol/vol) markedly inhibited microbial growth and produced a product with acceptable taste. Tropical spices may prove useful in preservation of fruit juices by hurdle technology.

Bacteria↗

The composition of subgingival microflora in two groups of children with and without primary dentition alveolar bone loss.

The is study examined the relationships between the microbial composition of the subgingival plaque, contact loss caused by caries and alveolar bone loss (ABL) in primary molars. The study included 10 children with contact loss in at least two sites, one with ABL and one without ABL, and 10 children without ABL with sites with or without contact loss. The microbial composition of subgingival plaque was examined by dark-field microscopy and by cultures of total anaerobic bacteria, Actinobacillus actinomycetemcomitans (Aa) and Porphyromonas gingivalis (Pg). Dark-field microscopy confirmed that spirochetes and motile rods may be part of the indigenous flora of the oral cavity. More spirochetes and motile rods were observed in sites with ABL than in control sites in the same subject and control subjects without ABL. Lower numbers of cocci were seen in sites with ABL than in sites in children without ABL, but a significant difference was not observed between sites with ABL and healthy sites within the same subjects. No significant differences in the dark-field values were evident in sites without ABL, with or without contact loss. Aa and Pg were found in children and sites with or without ABL. In sites with Aa, larger proportions of spirochetes, lower values of cocci, and more colonies of Pg were evident. No significant differences in anaerobic bacteria were evident between sites with or without contact loss or with or without ABL. ABL in the primary dentition was found to be related to the microbial composition of the subgingival plaque, but not related to contact loss per se.

Aggregatibacter actinomycetemcomitans↗

[Hygienic processing of dental transmission instruments (handpieces and instruments, turbines) in dental practice].

The efficacy of a steam disinfection method for the processing of used instruments in dental practice was tested with 274 high-speed turbines and handpieces. The instruments treated with streaming steam were both taken out of the dental practice of treatment and artificially contaminated with five different test-microorganisms (E. coli, P. aeruginosa, S. aureus, E. faecium, C. albicans) and different concentrations of serum (1%, 10%, 20%). In spite of the narrow channels of these instruments a microbial reduction of more than 5 log10 steps could be achieved in all cases. Thus dental high-speed turbines and handpieces can reliably be disinfected with streaming steam.

Colony Count, Microbial↗

A comparative, qualitative and quantitative antimicrobial efficacies of mouthrinses containing chlorhexidine gluconate and essential oils.

A project was launched to evaluate and compare antimicrobial efficacy of Hexidine and Listerine over placebo in 10 day human experimental gingivitis study. A rigid study schedule for subject compliance spanning well over 3 months was sorted out and volunteers recruited for study rinsed all the 3 assigned mouthrinses containing (a) chlorhexidine gluconate, (b) "essential oils" and (c) flavoured distilled water one after the other at certain prefixed intervals. After 10 days of assigned mouthrinse regimen, where the assigned mouthrinse was the only method practiced by the volunteers for oral hygiene, Supragingival Plaque was quantitatively and qualitatively assayed. Qualitatively supragingival plaque was assayed by Gram staining (Direct smear and Thioglycollate Broth) and growth characteristics i.e; Aerobic, Microaerophilic and Anaerobic growth was noted. Quantitatively plaque was assayed by calculating total microbial load per tooth by preparing Mafarland Nephelometer standard and Spectrophotometric analysis. It is concluded that Hexidine and Listerine exert similar antimicrobial efficacy in 10 days experimental gingivitis study. Hexidine and Listerine exert their antimicrobial influence through reduction of total Aerobes and Anaerobes reducing total microbial load per tooth by 58% and 53% respectively as compared to placebo.

Adult↗