A Citrus Fruit Extract High in Polyphenols Beneficially Modulates the Gut Microbiota of Healthy Human Volunteers in a Validated In Vitro Model of the Colon.

The effect of a Citrus Fruit Extract high in the polyphenols hesperidin and naringin (CFE) on modulation of the composition and activity of the gut microbiota was tested in a validated, dynamic in vitro model of the colon (TIM-2). CFE was provided at two doses (250 and 350 mg/day) for 3 days. CFE led to a dose-dependent increase in Roseburia, Eubacterium ramulus, and Bacteroides eggerthii. There was a shift in production of short-chain fatty acids, where acetate production increased on CFE, while butyrate decreased. In overweight and obesity, acetate has been shown to increase fat oxidation when produced in the distal gut, and stimulate secretion of appetite-suppressive neuropeptides. Thus, the data in the in vitro model point towards mechanisms underlying the effects of the polyphenols in CFE with respect to modulation of the gut microbiota, both in composition and activity. These results should be confirmed in a clinical trial.

Inclusion of Soluble Fiber in the Gestation Diet Changes the Gut Microbiota, Affects Plasma Propionate and Odd-Chain Fatty Acids Levels, and Improves Insulin Sensitivity in Sows.

The transition from pregnancy to lactation is characterized by a progressive decrease in insulin sensitivity. Propionate increases with dietary fiber consumption and has been shown to improve insulin sensitivity. Recent studies suggest that plasma odd-chain fatty acids [OCFAs; pentadecanoic acid (C15:0) and heptadecanoic acid (C17:0)] that inversely correlated with insulin resistance are synthesized endogenously from gut-derived propionate. The present study investigated the effects of soluble fiber during gestation on gut microbiota, plasma non-esterified fatty acids and insulin sensitivity in sows. Sows were allocated to either control or 2.0% guar gum plus pregelatinized waxy maize starch (SF) dietary treatment during gestation. The SF addition changes the structure and composition of gut microbiota in sows. Genus Eubacterium increased by SF addition may promote intestinal propionate production. Moreover, the dietary SF increased circulating levels of plasma OCFAs, especially C17:0. The SF-fed sows had a higher insulin sensitivity and a lower systemic inflammation level during perinatal period. Furthermore, the plasma C15:0 and C17:0 was negatively correlated with the area under curve of plasma glucose after meal and plasma interleukin-6. In conclusion, dietary SF improves insulin sensitivity and alleviates systemic inflammation in perinatal sows, potentially related to its stimulating effect on propionate and OCFAs production.

Dose-Dependent Alterations to In Vitro Human Microbiota Composition and Butyrate Inhibition by a Supercritical Carbon Dioxide Hops Extract.

Hop cones (Humulus lupulus L.) have been used throughout history as an additive in beer brewing and as herbal supplements with medicinal and culinary properties. The objective of this study was to ascertain the effect of a range of concentrations of a supercritical CO2 extract of hops on the composition and metabolism of human gut bacterial communities using in vitro batch culture systems. Fermentations were conducted over 24 h using a mixed human fecal inoculum. Microbial metabolism was assessed by measuring organic acid production and microbial community alterations were determined by 16S rRNA gene sequencing. Butyrate, an important short chain fatty acid in maintaining colonic well-being, decreased at elevated concentrations of hops, which may partly be accounted for by the concomitant reduction of Eubacterium and Coprococcus, known butyrate-producing genera, and also the inhibition of Bifidobacterium, a beneficial organism that has a butyrogenic effect through metabolic cross-feeding with intestinal commensals. The hops compounds also caused dose-dependent increases in the potentially pathogenic Enterobacteriaceae and potentially beneficial Akkermansia. Thus, hops compounds had a significant impact on the structure of the bacterial consortium, which warrants further study including human clinical trials.

Genome Engineering of Eubacterium limosum Using Expanded Genetic Tools and the CRISPR-Cas9 System.

Eubacterium limosum is one of the important bacteria in C1 feedstock utilization as well as in human gut microbiota. Although E. limosum has recently garnered much attention and investigation on a genome-wide scale, a bottleneck for systematic engineering in E. limosum is the lack of available genetic tools and an efficient genome editing platform. To overcome this limitation, we here report expanded genetic tools and the CRISPR-Cas9 system. We have developed an inducible promoter system that enables implementation of the CRISPR-Cas9 system to precisely manipulate target genes of the Wood-Ljungdahl pathway with 100% efficiency. Furthermore, we exploited the effectiveness of CRISPR interference to reduce the expression of target genes, exhibiting substantial repression of several genes in the Wood-Ljungdahl pathway and fructose-PTS system. These expanded genetic tools and CRISPR-Cas9 system comprise powerful and widely applicable genetic tools to accelerate functional genomic study and genome engineering in E. limosum.

Comparative analysis of the gut microbiota in distinct statin response patients in East China.

Statin response shows great interindividual variations. Recently, emerging studies have shown that gut microbiota is linked to therapeutic responses to drugs, including statins. However, the association between the gut bacteria composition and statin response is still unclear. In this study, gut microbiota of 202 hyperlipidemic patients with statin sensitive (SS) response and statin resistant (SR) response in East China were investigated by high throughput sequencing to compare the gut bacteria composition and biodiversity in distinct statin response patients. Higher biodiversity was detected in Group SS than Group SR. Specifically, group SS showed significantly increased proportion of genera Lactobacillus (P = 0.001), Eubacterium (P = 0.004), Faecalibacterium (P = 0.005), and Bifidobacterium (P = 0.002) and decreased proportion of genus Clostridium (P = 0.001) compared to Group SR. The results indicated that higher gut biodiversity was associated with statin sensitive response. The increased genera Lactobacillus, Eubacterium, Faecalibacterium, Bifidobacterium, and decreased genus Clostridium in patient gut microbiota may predict patient's statin response, and hence may guide statin dosage adjustments.

Effect of Dietary Chestnut or Quebracho Tannin Supplementation on Microbial Community and Fatty Acid Profile in the Rumen of Dairy Ewes.

Ruminants derived products have a prominent role in diets and economy worldwide; therefore, the capability to control the rumen microbial ecosystem, for ameliorating their quality, is of fundamental importance in the livestock sector. The aim of this study was to evaluate the effect of dietary supplementation with chestnut and quebracho tannins on microbial community and fatty acid profile, in the rumen fluid of dairy ewes. Multivariate analysis of PCR-DGGE profiles of rumen microbial communities showed a correlation among the presence of chestnut or quebracho in the diet, the specific Butyrivibrio group DGGE profiles, the increase in 18:3 cis9, cis12, and cis15; 18:2 cis9 and cis12; 18:2 cis9 and trans11; 18:2 trans11 and cis15; and 18:1 trans11 content, and the decrease in 18:0 concentration. Phylogenetic analysis of DGGE band sequences revealed the presence of bacteria representatives related to the genera Hungatella, Ruminococcus, and Eubacterium and unclassified Lachnospiraceae family members, suggesting that these taxa could be affected by tannins presence in the diets. The results of this study showed that tannins from chestnut and quebracho can reduce the biohydrogenation of unsaturated fatty acids through changes in rumen microbial communities.

Effect of smokeless tobacco products on human oral bacteria growth and viability.

To evaluate the toxicity of smokeless tobacco products (STPs) on oral bacteria, seven smokeless tobacco aqueous extracts (STAEs) from major brands of STPs and three tobacco-specific N-nitrosamines (TSNAs) were used in a growth and viability test against 38 oral bacterial species or subspecies. All seven STAEs showed concentration-dependent effects on the growth and viability of tested oral bacteria under anaerobic culture conditions, although there were strain-to-strain variations. In the presence of 1 mg/ml STAEs, the growth of 4 strains decreased over 0.32-2.14 log10 fold, while 14 strains demonstrated enhanced growth of 0.3-1.76 log10 fold, and the growth of 21 strains was not significantly affected. In the presence of 10 mg/ml STAEs, the growth of 17 strains was inhibited 0.3-2.11 log10 fold, 18 strains showed enhanced growth of 0.3-0.97 log10 fold, and 4 strains were not significantly affected. In the presence of 50 mg/ml STAEs, the growth of 32 strains was inhibited 0.3-2.96 log10 fold, 8 strains showed enhanced growth of 0.3-1.0 log10 fold, and 2 strains were not significantly affected. All seven STAEs could promote the growth of 4 bacterial strains, including Eubacterium nodatum, Peptostreptococcus micros, Streptococcus anginosus, and Streptococcus constellatus. Exposure to STAEs modulated the viability of some bacterial strains, with 21.1-66.5% decrease for 4 strains at 1 mg/ml, 20.3-85.7% decrease for 10 strains at 10 mg/ml, 20.0-93.3% decrease for 27 strains at 50 mg/ml, and no significant effect for 11 strains at up to 50 mg/ml. STAEs from snuffs inhibited more tested bacterial strains than those from snus indicating that the snuffs may be more toxic to the oral bacteria than snus. For TSNAs, cell growth and viability of 34 tested strains were not significantly affected at up to 100 µg/ml; while the growth of P. micros was enhanced 0.31-0.54 log10 fold; the growth of Veillonella parvula was repressed 0.33-0.36 log10 fold; and the cell viabilities of 2 strains decreased 56.6-69.9%. The results demonstrate that STAEs affected the growth of some types of oral bacteria, which may affect the healthy ecological balance of oral bacteria in humans. On the other hand, TSNAs did not significantly affect the growth of the oral bacteria.

Impact of dietary resistant starch type 4 on human gut microbiota and immunometabolic functions.

Dietary modulation of the gut microbiota impacts human health. Here we investigated the hitherto unknown effects of resistant starch type 4 (RS4) enriched diet on gut microbiota composition and short-chain fatty acid (SCFA) concentrations in parallel with host immunometabolic functions in twenty individuals with signs of metabolic syndrome (MetS). Cholesterols, fasting glucose, glycosylated haemoglobin, and proinflammatory markers in the blood as well as waist circumference and % body fat were lower post intervention in the RS4 group compared with the control group. 16S-rRNA gene sequencing revealed a differential abundance of 71 bacterial operational taxonomic units, including the enrichment of three Bacteroides species and one each of Parabacteroides, Oscillospira, Blautia, Ruminococcus, Eubacterium, and Christensenella species in the RS4 group. Gas chromatography-mass spectrometry revealed higher faecal SCFAs, including butyrate, propionate, valerate, isovalerate, and hexanoate after RS4-intake. Bivariate analyses showed RS4-specific associations of the gut microbiota with the host metabolic functions and SCFA levels. Here we show that dietary RS4 induced changes in the gut microbiota are linked to its biological activity in individuals with signs of MetS. These findings have potential implications for dietary guidelines in metabolic health management.

Bloom and bust: intestinal microbiota dynamics in response to hospital exposures and Clostridium difficile colonization or infection.

BACKGROUND: Clostridium difficile infection (CDI) is the leading infectious cause of nosocomial diarrhea. Hospitalized patients are at increased risk of developing CDI because they are exposed to C. difficile spores through contact with the hospital environment and often receive antibiotics and other medications that can disrupt the integrity of the indigenous intestinal microbiota and impair colonization resistance. Using whole metagenome shotgun sequencing, we examined the diversity and composition of the fecal microbiota in a prospective cohort study of 98 hospitalized patients. RESULTS: Four patients had asymptomatic C. difficile colonization, and four patients developed CDI. We observed dramatic shifts in the structure of the gut microbiota during hospitalization. In contrast to CDI cases, asymptomatic patients exhibited elevated relative abundance of potentially protective bacterial taxa in their gut at the onset of C. difficile colonization. Use of laxatives was associated with significant reductions in the relative abundance of Clostridium and Eubacterium; species within these genera have previously been shown to enhance resistance to CDI via the production of secondary bile acids. Cephalosporin and fluoroquinolone exposure decreased the frequency of Clostridiales Family XI Incertae Sedis, a bacterial family that has been previously associated with decreased CDI risk. CONCLUSIONS: This study underscores the detrimental impact of antibiotics as well as other medications, particularly laxatives, on the intestinal microbiota and suggests that co-colonization with key bacterial taxa may prevent C. difficile overgrowth or the transition from asymptomatic C. difficile colonization to CDI.

Relationship of Enhanced Butyrate Production by Colonic Butyrate-Producing Bacteria to Immunomodulatory Effects in Normal Mice Fed an Insoluble Fraction of Brassica rapa L.

This study was performed to determine the effects of feeding a fiber-rich fraction of Brassica vegetables on the immune response through changes in enteric bacteria and short-chain fatty acid (SCFA) production in normal mice. The boiled-water-insoluble fraction of Brassica rapa L. (nozawana), which consists mainly of dietary fiber, was chosen as a test material. A total of 31 male C57BL/6J mice were divided into two groups and housed in a specific-pathogen-free facility. The animals were fed either a control diet or the control diet plus the insoluble B. rapa L. fraction for 2 weeks and sacrificed to determine microbiological and SCFA profiles in lower-gut samples and immunological molecules. rRNA-based quantification indicated that the relative population of Bacteroidetes was markedly lower in the colon samples of the insoluble B. rapa L. fraction-fed group than that in the controls. Populations of the Eubacterium rectale group and Faecalibacterium prausnitzii, both of which are representative butyrate-producing bacteria, doubled after 2 weeks of fraction intake, accompanying a marginal increase in the proportion of colonic butyrate. In addition, feeding with the fraction significantly increased levels of the anti-inflammatory cytokine interleukin-10 (IL-10) and tended to increase splenic regulatory T cell numbers but significantly reduced the population of cells expressing activation markers. We demonstrated that inclusion of the boiled-water-insoluble fraction of B. rapa L. can alter the composition of the gut microbiota to decrease the numbers of Bacteroidetes and to increase the numbers of butyrate-producing bacteria, either of which may be involved in the observed shift in the production of splenic IL-10.

Metronidazole and amoxicillin as adjuncts to scaling and root planing for the treatment of type 2 diabetic subjects with periodontitis: 1-year outcomes of a randomized placebo-controlled clinical trial.

AIM: To evaluate the clinical and microbiological effects of the use of metronidazole (MTZ) + amoxicillin (AMX) as adjuncts to scaling and root planing (SRP) for the treatment of chronic periodontitis (ChP) in type 2 diabetic subjects. MATERIAL AND METHODS: Fifty-eight type 2 diabetic subjects (n = 29/group) with generalized ChP were randomly assigned to receive SRP alone or with MTZ [400 mg/thrice a day (TID)]+AMX (500 mg/TID) for 14 days. Subgingival biofilm samples were analyzed by qPCR for the presence of seven periodontal pathogens. Subjects were monitored at baseline, 3, 6 and 12 months post-therapies. RESULTS: The group receiving SRP+MTZ+AMX presented greater mean probing depth (PD) reduction and clinical attachment gain, a lower number of sites with PD ≥5 mm (primary outcome variable) and a reduced number of subjects with ≥9 of these residual pockets than the control group at 1-year post-therapy (p < 0.05). The antibiotic-treated group also presented reduced levels and greater decreases of the three red complex species, Eubacterium nodatum and Prevotella intermedia, compared to the control group at 1 year (p < 0.05). CONCLUSIONS: The adjunctive use of MTZ+AMX significantly improved the clinical and microbiological outcomes of SRP in the treatment of type 2 diabetic subjects with ChP.

Continuous syngas fermentation for the production of ethanol, n-propanol and n-butanol.

Syngas fermentation to fuels is a technology on the verge of commercialization. Low cost of fermentation medium is important for process feasibility. The use of corn steep liquor (CSL) instead of yeast extract (YE) in Alkalibaculum bacchi strain CP15 bottle fermentations reduced the medium cost by 27% and produced 78% more ethanol. When continuous fermentation was performed in a 7-L fermentor, 6g/L ethanol was obtained in the YE and YE-free media. When CSL medium was used in continuous fermentation, the maximum produced concentrations of ethanol, n-propanol and n-butanol were 8 g/L, 6 g/L and 1 g/L, respectively. n-Propanol and n-butanol were not typical products of strain CP15. A 16S rRNA gene-based survey revealed a mixed culture in the fermentor dominated by A. bacchi strain CP15 (56%) and Clostridium propionicum (34%). The mixed culture presents an opportunity for higher alcohols production from syngas.

Efficacy of a new mouth rinse formulation based on 0.07% cetylpyridinium chloride in the control of plaque and gingivitis: a 6-month randomized clinical trial.

AIM: To assess the efficacy of a 0.07% cetylpyridinium chloride (CPC) mouth rinse in the control of plaque and gingival inflammation during a 6-month period. MATERIAL AND METHODS: Adult subjects with moderate gingivitis were selected [≥40% bleeding on marginal probing (BOMP)]. After retrieving microbiological samples and evaluating the clinical parameters (plaque, BOMP and stain indexes), a professional prophylaxis was performed and subjects were randomly assigned to the test (CPC mouth rinse) or to the placebo group. Subjects were re-assessed after 3 and 6 months. RESULTS: A total of 67 patients (35 test, 32 placebo) were included in the analysis. At 6 months, intra-group significant plaque reductions were observed in the test group (0.691, p < 0.001), but not in the placebo (0.181, p = 0.653). At 6 months, the mean BOMP values were lower in the test group (p = 0.052). Changes between baseline and 6 months were significantly higher in the test group both for plaque (p = 0.002) and BOMP (p = 0.037) when compared with the placebo. A microbiological impact was observed in the test group, especially for Prevotella intermedia. CONCLUSION: The evaluated 0.07% CPC-based mouth rinse, used three times per day adjunctively to mechanical tooth cleaning, prevents plaque accumulation and gingival inflammation, as compared to the placebo, for at least 6 months.

Comparative antibacterial efficacies of hydrodynamic and ultrasonic irrigation systems in vitro.

INTRODUCTION: To ensure root canal treatment success, endodontic microbiota should be efficiently reduced. The in vitro bactericidal effects of a hydrodynamic system and a passive ultrasonic irrigation system were compared. METHODS: Single-rooted extracted teeth (n = 250) were contaminated with suspensions of Enterococcus faecalis ATCC 29212, mixed aerobic cultures, or mixed anaerobic cultures. First, the antibacterial effects of the hydrodynamic system (RinsEndo), a passive ultrasonic irrigation system (Piezo smart), and manual rinsing with 0.9% NaCl (the control) were compared. Colony-forming units were counted. Second, the 2 systems were used with 1.5% sodium hypochlorite (NaOCl) alone or NaOCl + 0.2% chlorhexidine (CHX). The colony-forming units in the treated and untreated roots were determined during a period of 5 days. RESULTS: Both irrigation systems reduced bacterial numbers more effectively than manual rinsing (P < .001). With NaCl, ultrasonic activated irrigation reduced bacterial counts significantly better than hydrodynamic irrigation (P = .042). The NaOCl + CHX combination was more effective than NaOCl alone for both systems (P < .001), but hydrodynamic irrigation was more effective with NaOCl + CHX than the passive ultrasonic irrigation system. CONCLUSIONS: Both irrigation systems, when combined with NaOCl + CHX, removed bacteria from root canals.

Monomer and linkage type of galacto-oligosaccharides affect their resistance to ileal digestion and prebiotic properties in rats.

A detailed study was performed to compare the in vivo ileal digestibility and modulatory effects in fecal microbiota of novel galacto-oligosaccharides (GOS) derived from lactulose [GOS-Lu; degree of polymerization (DP) ≥2, 14.0% trisaccharides] and commercial GOS derived from lactose (GOS-La; DP ≥3, 35.1% trisaccharides) in growing rats (5 wk old). Rats were fed either a control diet or diets containing 1% (wt:wt) of GOS-Lu or GOS-La for 14 d. Quantitative analysis of carbohydrates from dietary and ileal samples demonstrated that the trisaccharide fraction of GOS-Lu was significantly more resistant to gut digestion than that from GOS-La, as indicated by their ileal digestibility rates of 12.5 ± 2.6% and 52.9 ± 2.7%, respectively, whereas the disaccharide fraction of GOS-Lu was fully resistant to the extreme environment of the upper digestive tract. The low ileal digestibility of GOS-Lu was due to the great resistance of galactosyl-fructoses to mammalian digestive enzymes, highlighting the key role played by the monomer type and linkage involved in the oligosaccharide chain. The partial digestion of GOS-La trisaccharides showed that glycosidic linkages (1→6) and (1→2) between galactose and glucose monomers were significantly more resistant to in vivo gastrointestinal digestion than the linkage (1→4) between galactose units. The absence of GOS-La and GOS-Lu digestion-resistant oligosaccharides in fecal samples indicated that they were readily fermented within the large intestine, enabling both types of GOS to have a potential prebiotic function. Indeed, compared with controls, the GOS-Lu group had significantly more bifidobacteria in fecal samples after 14 d of treatment. The number of Eubacterium rectale also was greater in the GOS-Lu and GOS-La groups than in controls. These novel data support a direct relationship between patterns of resistance to digestion and prebiotic properties of GOS.

Adjunctive azithromycin in the treatment of aggressive periodontitis: microbiological findings of a 12-month randomized clinical trial.

OBJECTIVES: To compare the subgingival microbiological outcomes of azithromycin or placebo as adjuncts to scaling and root planing (SRP) in the treatment of aggressive periodontitis (AgP), and to secondarily evaluate the microbiological effect of supragingival scaling in AgP patients. METHODS: Twenty-four AgP subjects 13-26 years of age received a 15-day programme of supragingival scaling (SC) and were then randomly assigned to SRP with systemic azithromycin or placebo. Subgingival samples were taken with sterile paper points at baseline, 15 days after SC, and at 3, 6 and 12 months following SRP. Microbiological analysis was performed by the checkerboard DNA-DNA hybridization. RESULTS: Changes in bacterial levels from baseline to 15 days after SC were similar in the 2 groups. When subjects were analysed as a single group, significant reductions after SC were observed for Actinomyces gerencseriae, Capnocytophaga ochracea, and Treponema denticola. During the 12-month follow-up, levels of most of the bacteria decreased in both groups in a similar pattern. For instance, Actinomyces israelli, Veillonella parvula, Streptococcus gordonii, C. ochracea, Eikenella corrodens, Eubacterium nodatum, Fusobacterium periodonticum and Fusobacterium nucleatum ssp. polymorphum decreased significantly within the groups. CONCLUSIONS: Azithromycin was ineffective in lowering the subgingival levels of important putative periodontal pathogens in young AgP subjects compared to placebo. CLINICAL SIGNIFICANCE: Scaling and root planing with adjunctive systemic azithromycin provides little additional benefit compared to placebo in reductions of major subgingival periodontal pathogens.

A comparative evaluation of the antibacterial efficacy of honey in vitro and antiplaque efficacy in a 4-day plaque regrowth model in vivo: preliminary results.

BACKGROUND: Honey has a potent broad-spectrum antibacterial action that may make it suitable for "anti-infective" treatment of periodontal disease. The aims of this study are as follows: 1) to evaluate the antibacterial efficacy of honey against oral bacteria and compare the same with 0.2% chlorhexidine; and 2) to compare antiplaque efficacy in vivo with chlorhexidine. METHODS: The study was conducted in two parts. In the in vitro part, the inhibitory effects of three test agents, 0.2% chlorhexidine gluconate, honey mouthwash, and saline, against six oral bacteria at concentrations of 1, 2, 4, 8, 16, 32, 64, 128, 256, and 512 µg/mL were tested in duplicate. The minimum inhibitory concentration (MIC) was set as the lowest concentration of the agent that completely inhibited the growth of the test species. The in vivo part consisted of a double-masked parallel clinical trial based on a 4-day plaque regrowth model. Sixty-six volunteers, 20 to 24 years of age, participated in the study, and the plaque scores were compared at baseline and at the end of 4 days. The Kruskal-Wallis test was used for significance, and the Mann-Whitney U test was used for pairwise comparison of the groups. The mean plaque scores were 1.77 ± 0.86, 1.64 ± 0.90, and 3.27 ± 0.83 for groups 1, 2, and 3, respectively. RESULTS: The honey mouthrinse effectively inhibited the six tested microorganisms. The chlorhexidine gluconate rinse had the lowest MICs compared with honey and saline rinses for all test species examined. The in vivo results revealed that plaque formation was inhibited/reduced by chlorhexidine and honey rinses. CONCLUSION: Honey has antibacterial action against tested oral microorganisms and also has antiplaque action.

Probiotics to minimize the disruption of faecal microbiota in healthy subjects undergoing antibiotic therapy.

A novel combination of culturing and DNA-based terminal restriction fragment length polymorphism (TRFLP) analysis was used to investigate the effect of probiotics on antibiotic-induced gut microbiota alterations to determine if a probiotic preparation containing bifidobacteria and lactobacilli, taken during and after antibiotic therapy, can minimize antibiotic disturbance of faecal microbiota. Healthy subjects administered amoxicillin/clavulanate were randomized and concomitantly received a placebo or probiotic mixture. The primary end point was similarity of faecal microbiota as determined by culturing and TRFLP from subjects taking probiotics compared to those taking a placebo measured by comparing data from baseline to post-treatment for each subject. TRFLP analysis revealed a high subject to subject variation in the baseline faecal microbiota. The most common antibiotic-induced disturbance was a relative increase in Clostridium, Eubacterium, Bacteroides and Enterobacteraceae. The mean similarity to the baseline increased over time in both treatment groups, although the probiotic group was less disturbed according to both TRFLP and culture data. The culture method revealed that post-antibiotic faecal microbiota in probiotic-consuming subjects were more similar to the baseline microbiota than the control group (P=0.046). Changes in Enterobactereaceae (P=0.006) and Bifidobacterium (P=0.030) counts were significantly different between the groups. Analysis of TRFLP data reinforced the trend between groups but was not statistically significant (P=0.066). This study indicates this mixture of probiotics promotes a more rapid return to pre-antibiotic baseline faecal bacterial microbiota.

Photodynamic therapy as an adjunct to non-surgical periodontal treatment: a randomized, controlled clinical trial.

BACKGROUND: Recent preclinical and clinical data have suggested a potential benefit of photodynamic therapy (PDT) in the treatment of periodontitis. However, there are very limited data from controlled clinical trials evaluating the effect of PDT in the treatment of periodontitis. The aim of this study was to evaluate the clinical and microbiologic effects of the adjunctive use of PDT to non-surgical periodontal treatment. METHODS: Twenty-four subjects with chronic periodontitis were randomly treated with scaling and root planing followed by a single episode of PDT (test) or scaling and root planing alone (control). Full-mouth plaque score (FMPS), full-mouth bleeding score (FMBS), probing depth (PD), gingival recession, and clinical attachment level (CAL) were measured at baseline and 3 and 6 months after therapy. Primary outcome variables were changes in PD and CAL. Microbiologic evaluation of Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans), Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia (previously T. forsythensis), Treponema denticola, Parvimonas micra (previously Peptostreptococcus micros or Micromonas micros), Fusobacterium nucleatum, Campylobacter rectus, Eubacterium nodatum, Eikenella corrodens, and Capnocytophaga spp. was performed at baseline and 3 and 6 months following therapy by using a commercially available polymerase chain reaction test. RESULTS: At 3 and 6 months after treatment, there were no statistically significant differences between the groups with regard to CAL, PD, FMPS, or microbiologic changes. At 3 and 6 months, a statistically significantly greater improvement in FMBS was found in the test group. CONCLUSION: The additional application of a single episode of PDT to scaling and root planing failed to result in an additional improvement in terms of PD reduction and CAL gain, but it resulted in a significantly higher reduction in bleeding scores compared to scaling and root planing alone.