Microbiological and clinical effects of probiotics and antibiotics on nonsurgical treatment of chronic periodontitis: a randomized placebo- controlled trial with 9-month follow-up

ABSTRACT Objective: The aim of this double-blind, placebo-controlled and parallel- arm randomized clinical trial was to evaluate the effects of Lactobacillus rhamnosus SP1-containing probiotic sachet and azithromycin tablets as an adjunct to nonsurgical therapy in clinical parameters and in presence and levels of Tannerella forsythia, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. Material and Methods: Forty-seven systemically healthy volunteers with chronic periodontitis were recruited and monitored clinically and microbiologically at baseline for 3, 6 and 9 months after therapy. Subgingival plaque samples were collected from four periodontal sites with clinical attachment level ≥1 mm, probing pocket depth ≥4 mm and bleeding on probing, one site in each quadrant. Samples were cultivated and processed using the PCR technique. Patients received nonsurgical therapy including scaling and root planing (SRP) and were randomly assigned to a probiotic (n=16), antibiotic (n = 16) or placebo (n = 15) group. L. rhamnosus SP1 was taken once a day for 3 months. Azithromycin 500mg was taken once a day for 5 days. Results: All groups showed improvements in clinical and microbiological parameters at all time points evaluated. Probiotic and antibiotic groups showed greater reductions in cultivable microbiota compared with baseline. The placebo group showed greater reduction in number of subjects with P. gingivalis compared with baseline. However, there were no significant differences between groups. Conclusions: The adjunctive use of L. rhamnosus SP1 sachets and azithromycin during initial therapy resulted in similar clinical and microbiological improvements compared with the placebo group

Chronic Inflammation as a Link between Periodontitis and Carcinogenesis

Periodontitis is characterized by a chronic inflammation produced in response to a disease-associated multispecies bacterial community in the subgingival region. Although the inflammatory processes occur locally in the oral cavity, several studies have determined that inflammatory mediators produced during periodontitis, as well as subgingival species and bacterial components, can disseminate from the oral cavity, contributing therefore, to various extraoral diseases like cancer. Interestingly, carcinogenesis associated with periodontal species has been observed in both the oral cavity and in extra oral sites. In this review, several studies were summarized showing a strong association between orodigestive cancers and poor oral health, presence of periodontitis-associated bacteria, tooth loss, and clinical signs of periodontitis. Proinflammatory pathways were also summarized. Such pathways are activated either by mono- or polymicrobial infections, resulting in an increase in the expression of proinflammatory molecules such as IL-6, IL-8, IL-1β, and TNF-α. In addition, it has been shown that several periodontitis-associated species induce the expression of genes related to cell proliferation, cell cycle, apoptosis, transport, and immune and inflammatory responses. Intriguingly, many of these pathways are linked to carcinogenesis. Among them, the activation of Toll-like receptors (TLRs) and antiapoptotic pathways (such as the PI3K/Akt, JAK/STAT, and MAPK pathways), the reduction of proapoptotic protein expression, the increase in cell migration and invasion, and the enhancement in metastasis are addressed. Considering that periodontitis is a polymicrobial disease, it is likely that mixed species promote carcinogenesis both in the oral cavity and in extra oral tissues and probably—as observed in periodontitis—synergistic and/or antagonistic interactions occur between microbes in the community. To date, a good amount of studies has allowed us to understand how monospecies infections activate pathways involved in tumorigenesis; however, more studies are needed to determine the combined effect of oral species in carcinogenesis

Microbial signatures of health, gingivitis, and periodontitis.

The subgingival crevice harbors diverse microbial communities. Shifts in the composition of these communities occur with the development of gingivitis and periodontitis, which are considered as successive stages of periodontal health deterioration. It is not clear, however, to what extent health- and gingivitis-associated microbiota are protective, or whether these communities facilitate the successive growth of periodontitis-associated taxa. To further our understanding of the dynamics of the microbial stimuli that trigger disruptions in periodontal homeostasis, we reviewed the available literature with the aim of defining specific microbial signatures associated with different stages of periodontal dysbiosis. Although several studies have evaluated the subgingival communities present in different periodontal conditions, we found limited evidence for the direct comparison of communities in health, gingivitis, and periodontitis. Therefore, we aimed to better define subgingival microbiome shifts by merging and reanalyzing, using unified bioinformatic processing strategies, publicly available 16S ribosomal RNA gene amplicon datasets of periodontal health, gingivitis, and periodontitis. Despite inherent methodological differences across studies, distinct community structures were found for health, gingivitis, and periodontitis, demonstrating the specific associations between gingival tissue status and the subgingival microbiome. Consistent with the concept that periodontal dysbiosis is the result of a process of microbial succession without replacement, more species were detected in disease than in health. However, gingivitis-associated communities were more diverse than those from subjects with periodontitis, suggesting that certain species ultimately become dominant as dysbiosis progresses. We identified the bacterial species associated with each periodontal condition and prevalent species that do not change in abundance from one state to another (core species), and we also outlined species co-occurrence patterns via network analysis. Most periodontitis-associated species were rarely detected in health but were frequently detected, albeit in low abundance, in gingivitis, which suggests that gingivitis and periodontitis are a continuum. Overall, we provide a framework of subgingival microbiome shifts, which can be used to generate hypotheses with respect to community assembly processes and the emergence of periodontal dysbiosis

The normal chain length distribution of the O antigen is required for the interaction of Shigella flexneri 2a with polarized Caco-2 cells

Shigella flexneri causes bacillary dysentery in humans. Essential to the establishment of the disease is the invasion of the colonic epithelial cells. Here we investigated the role of the lipopolysaccharide (LPS) O antigen in the ability of S. flexaeri to adhere to and invade polarized Caco-2 cells. The S. flexneri 2a O antigen has two preferred chain lengths: a short O antigen (S-OAg) regulated by the WzzB protein and a very long O antigen (VL-OAg) regulated by Wzz(pHS2). Mutants with defined deletions of the genes required for O-antigen assembly and polymerization were constructed and assayed for their abilities to adhere to and enter cultured epithelial cells. The results show that both VL- and S-OAg are required for invasion through the basolateral cell membrane. In contrast, the absence of O antigen does not impair adhesion. Purified LPS does not act as a competitor for the invasion of Caco-2 cells by the wild-type strain, suggesting that LPS is not directly involved in the internalization process by epithelial cells

Helicobacter pylori in human health and disease: Mechanisms for local gastric and systemic effects

© The Author(s) 2018. Helicobacter pylori (H. pylori ) is present in roughly 50% of the human population worldwide and infection levels reach over 70% in developing countries. The infection has classically been associated with different gastro-intestinal diseases, but also with extra gastric diseases. Despite such associations, the bacterium frequently persists in the human host without inducing disease, and it has been suggested that H. pylori may also play a beneficial role in health. To understand how H. pylori can produce such diverse effects in the human host, several studies have focused on understanding the local and systemic effects triggered by this bacterium. One of the main mechanisms by which H. pylori is thought to damage the host is by inducing local and systemic inflammation. However, more recently, studies are beginning to focus on the effects of H. pylori and its metabolism on the gastric and intestinal microbiome. The objective of this review is to discuss how H. pyl

The <i>S. flexneri</i> S-OAg is required for acid resistance.

<p>LPS profiles (A) and acid resistance (B) of <i>S. flexneri</i> 2457T, mutants in the chain length regulators and mutants complemented with homologous or heterologous chain length regulators. Strains are 2457T (wt), MSF102 (Δ<i>wzzB</i>), MSF107 (Δ<i>wzz</i>_pHS2::<i>aph</i>), MSF209 (Δ<i>wzzB</i> Δ<i>wzz</i>_pHS2::<i>aph</i>), MSF209/pJC139, MSF209/pJC144, MSF209/pMM110 and MSF209/pJC142. LPS samples from equal numbers of bacterial cells (1×10⁷ CFU) were loaded in each lane and were analyzed by Tricine-SDS-polyacrylamide gel electrophoresis on a 14% (w/v) acrylamide gel followed by silver staining. For acid resistance assays, cells were grown overnight in citrate-buffered LB (pH 5.5) and diluted 1∶1000 into the acid-challenge media. Survival is stated as a percentage of the inoculum. Averages±standard errors (error bars) are shown. Statistical significance was determined by a Student's <i>t</i> test. (**, <i>P</i> <0.01, ***, <i>P</i> <0.001).</p

Changes in the electrophoretic mobility of the LPS induced by moderate acidic conditions are not relevant to resistance to extreme acid.

<p>LPS profiles (A) and acid resistance (B) of <i>S. flexneri</i> 2457T (wt) and MSF102 (Δ<i>wzzB</i>) transformed with plasmids pRMCD108 (WzzB_(K267N)) or pRMCD127 (WzzB_(M32T)). Bacteria were grown at pH 7.0 or 5.5 and LPS samples were obtained. LPS samples from equal numbers of bacterial cells (1×10⁷ CFU) were loaded in each lane and were analyzed by Tricine-SDS-polyacrylamide gel electrophoresis on a 14% (w/v) acrylamide gel followed by silver staining. For acid resistance assays, cells were grown overnight in citrate-buffered LB (pH 5.5) and diluted 1∶1000 into the acid-challenge media. Survival is stated as a percentage of counts at time zero. Averages±standard errors (error bars) are shown. Statistical significance was determined by the two-way ANOVA and Bonferroni post test. No significant differences were found in bacteria previously grown at pH 5.5 (closed symbols) or pH 7.0 (open symbols).</p

Effect of pH on lipid A modifications in <i>S. flexneri</i>.

<p>³²P-labelled lipid A was isolated from bacteria grown in N-minimal medium at pH 7.0 (lanes 1, 3, 4 and 5) or 5.5 (lane 2). Lipid A species were resolved by TLC with the solvent system chloroform/pyridine/88% formic acid/water (50∶50∶16∶5, v/v). The strains are 2457T (wt), 2457T/pMM113 (wt/<i>eptA</i>⁺), MSF1650 (Δ<i>arnT</i>) and MSF1666 (Δ<i>pmrA</i>).</p