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Compositional profile of mucosal bacteriome of smokers and smokeless tobacco users

Gopinath D, Wie CC, Banerjee M, Thangavelu L, Kumar R P, Nallaswamy D, et al.

Clin Oral Investig, 2022 Feb;26(2):1647-1656.
PMID: 34436669 DOI: 10.1007/s00784-021-04137-7

INTRODUCTION: Smoked, and especially smokeless, tobacco are major causes of oral cancer globally. Here, we examine the oral bacteriome of smokers and of smokeless tobacco users, in comparison to healthy controls, using 16S rRNA gene sequencing.
METHODS: Oral swab samples were collected from smokers, smokeless tobacco users, and healthy controls (n = 44). Microbial DNA was extracted and the 16S rRNA gene profiled using the Illumina MiSeq platform. Sequencing reads were processed using DADA2, and taxonomical classification was performed using the phylogenetic placement method. Differentially abundant taxa were identified using DESeq2, while functional metagenomes based on KEGG orthology abundance were inferred using LIMMA.
RESULTS: A significantly higher microbial diversity was observed in smokeless tobacco users and smokers relative to controls (P 1.5; BH adj P

Matched MeSH terms: Mouth Mucosa/microbiology*
The induction of oral tolerance to Actinomyces viscosus in mice

Sosroseno W, Bird PS, Gemmell E, Seymour GJ

Oral Dis, 2006 Jul;12(4):387-94.
PMID: 16792724

To determine whether oral tolerance with the oral bacterium Actinomyces viscosus was inducible in mice.

Matched MeSH terms: Mouth Mucosa/microbiology*
The effect of immune status, age and genetic background on induction of oral tolerance to Actinomyces viscosus in mice

Sosroseno W, Herminajeng E, Bird P

Biomed Pharmacother, 2015 Mar;70:294-8.
PMID: 25776514 DOI: 10.1016/j.biopha.2014.12.039

The aim of the present study was to determine the effect of immune status, age and genetic background on the induction of oral tolerance to Actinomyces viscosus. Suppression of delayed type hypersensitivity (DTH) response and antigen-specific serum antibody levels could be induced in DBA/2 mice intragastrically and systemically immunized with A. viscocus, suggesting the induction of oral tolerance. In contrast, this immune suppression could be abrogated if the animals had been systemically immunized prior to the induction of oral tolerance with the same bacterium. Long-term systemic immunization prior to intragastric immunization with A. viscocus suppressed DTH response only. Cell transfer of this group of animals also suppressed DTH response in the donors, indicating the action of suppressor cells for inhibition of DTH response. Furthermore, oral tolerance to A. viscocus failed to occur in mice aged at 3 days and 1, 2, 4, 6 and 36 weeks old. Mice bearing H-2(d) haplotype were the most susceptible to oral tolerization, followed by H-2(b) and H-2(k). Therefore, the results of the presence study suggest that the induction of oral tolerance to A. viscosus in mice may be dependence on the immune status and genetic background but not age.

Matched MeSH terms: Mouth Mucosa/microbiology*
Fulltext Enhanced gastrointestinal survivability of recombinant Lactococcus lactis using a double coated mucoadhesive film approach

Tan EW, Tan KY, Phang LV, Kumar PV, In LLA

PLoS One, 2019;14(7):e0219912.
PMID: 31335895 DOI: 10.1371/journal.pone.0219912

Vaccine administration via the oral route is preferable to parenteral routes due to ease of administration. To date, most available oral vaccines comprises of live attenuated pathogens as oppose to peptide-based vaccines due to its low bioavailability within the gastrointestinal (GI) tract. Over the years, probiotic-based peptide delivery vehicles comprising of lactic acid bacteria such as Lactococcus lactis has emerged as an interesting alternative due to its generally recognized as safe (GRAS) status, a fully sequenced genome, transient gut colonization time, and is an efficient cellular factory for heterologous protein production. However, its survivability through the GI tract is low, thus better delivery approaches are being explored to improve its bioavailability. In this study, we employ the incorporation of a double coated mucoadhesive film consisting of sodium alginate and Lycoat RS 720 film as the inner coat. The formulated film exhibits good mechanical properties of tensile strength and percent elongation for manipulation and handling with an entrapment yield of 93.14±2.74%. The formulated mucoadhesive film is subsequently loaded into gelatin capsules with an outer enteric Eudragit L100-55 coating capable of a pH-dependent breakdown above pH 5.5 to protect against gastric digestion. The final product and unprotected controls were subjected to in vitro simulated gastrointestinal digestions to assess its survivability. The product demonstrated enhanced protection with an increase of 69.22±0.67% (gastric) and 40.61±8.23% (intestinal) survivability compared to unprotected controls after 6 hours of sequential digestion. This translates to a 3.5 fold increase in overall survivability. Owing to this, the proposed oral delivery system has shown promising potential as a live gastrointestinal vaccine delivery host. Further studies involving in vivo gastrointestinal survivability and mice immunization tests are currently being carried out to assess the efficacy of this novel oral delivery system in comparison to parenteral routes.

Matched MeSH terms: Mouth Mucosa/microbiology
Community-acquired vancomycin-resistant Enterococcus faecium: a case report from Malaysia

Raja NS, Karunakaran R, Ngeow YF, Awang R

J Med Microbiol, 2005 Sep;54(Pt 9):901-903.
PMID: 16091445 DOI: 10.1099/jmm.0.46169-0

Vancomycin-resistant enterococci (VRE) are formidable organisms renowned for their ability to cause infections with limited treatment options and their potential for transferring resistance genes to other Gram-positive bacteria. Usually associated with nosocomial infections, VRE are rarely reported as a cause of community-acquired infection. Presented here is a case of community-acquired infection due to vancomycin-resistant Enterococcus faecium. The patient had been applying herbal leaves topically to his cheek to treat a buccal space abscess, resulting in a burn of the overlying skin. From pus aspirated via the skin a pure culture of E. faecium was grown that was resistant to vancomycin with a MIC of >256 microg ml-1 by the E test and resistant to teicoplanin by disc diffusion, consistent with the VanA phenotype. The organism was suspected of contaminating the leaf and infecting the patient via the burnt skin. This case highlights the need for further studies on the community prevalence of VRE among humans and animals to define unrecognized silent reservoirs for VRE, which may pose a threat to public health.

Matched MeSH terms: Mouth Mucosa/microbiology
Detection of Candida albicans ADH1 and ADH2 mRNAs in human archival oral biopsy samples

Bakri MM, Cannon RD, Holmes AR, Rich AM

J Oral Pathol Med, 2014 Oct;43(9):704-10.
PMID: 24931506 DOI: 10.1111/jop.12193

The aim of this study was to investigate the relationship between expression of Candida albicans alcohol dehydrogenases (ADH) genes in archival formalin-fixed paraffin-embedded (FFPE) samples from biopsies of leukoplakia.

Matched MeSH terms: Mouth Mucosa/microbiology
Role of CD4 and CD8 T-cells in the induction of oral tolerance to Actinomyces viscosus in mice

Sosroseno W, Bird PS, Gemmell E, Seymour GJ

Oral Microbiol. Immunol., 2006 Jun;21(3):151-8.
PMID: 16626371

Mucosal presentation of Actinomyces viscosus results in the induction of antigen specific systemic suppressor cells in mice. The aim of the present study was to determine the phenotype of the suppressor cells responsible for the induction of oral tolerance to low doses of A. viscosus. When CD8 cell-depleted DBA/2 mice were intragastrically immunized and systemically immunized with A. viscosus, the delayed type hypersensitivity response was suppressed but not the levels of antigen specific serum antibodies. Adoptive transfer of orally tolerized CD4(+) cells to CD4(+)-depleted mice resulted in suppression of delayed type hypersensitivity response but not of the levels of antigen specific serum antibodies. In contrast, adoptive transfer of orally immunized CD8(+) cells to CD8(+)-depleted mice resulted in partially suppressed delayed type hypersensitivity response but significantly inhibited the levels of antigen specific serum antibodies. When orally tolerized CD8(+) cells were cocultured with systemically immunized CD8(+) cell-depleted spleen cells, splenic specific antibodies were inhibited. However, no suppression of splenic specific antibodies could be observed in the cultures containing orally tolerized CD4(+) cells and systemically immunized CD4(+) cell-depleted spleen cells. The results of the present study suggest that oral tolerance of humoral and cellular immunity induced by low doses of A. viscosus may be mediated by CD8(+) and CD4(+) cells, respectively.

Matched MeSH terms: Mouth Mucosa/microbiology*
Fulltext Distribution of Candida in the oral cavity and its differentiation based on the internally transcribed spacer (ITS) regions of rDNA

Zahir RA, Himratul-Aznita WH

Yeast, 2013 Jan;30(1):13-23.
PMID: 23208647 DOI: 10.1002/yea.2937

This study aimed to determine the distribution of Candida species in the oral cavity and differentiate the species based on PCR amplification, including HinfI and MspI digestion, in order to assess the effectiveness of using the rDNA region for species identification. Samples from saliva as well as palate, tongue and cheek mucosa surfaces were collected from 45 individuals, consisting of three groups: periodontal disease patients; denture-wearers; and the control group. The samples were serially diluted, spread on BHI and YPD agar plates and scored for colony-forming units (CFUs). Fifteen random candidal colonies were isolated and subjected to genomic DNA extraction, based on glass beads disruption. Four primers were used to amplify regions in the rDNA, and the ITSI-5.8S-ITSII PCR product was digested by HinfI and MspI restriction enzymes. The microbial loads on all sites of the denture-wearers were found to be significantly higher than control, while in the periodontal disease group only the microbial loads on the tongue were significantly higher than control. Meanwhile, there was no significant difference at other sites. The restriction fragment lengths of the clinical samples were compared to those of seven control species, allowing the differentiation of all seven species and the identification of 14 species from the clinical samples. The MspI restriction digest was not able to distinguish between C. albicans and C. dubliniensis, whereas the HinfI digest could not distinguish between C. tropicalis and C. parapsilosis. It was concluded that PCR-RFLP of the candidal rDNA region has potential for species identification. This study demonstrates the potential use of candidal rDNA as a means for identifying Candida species, based on genotype. The results also indicate the possibility of constructing genetic probes that target specific restriction fragments in the ITSI-5.8S-ITSII region, enabling swift and precise identification of Candida species.

Matched MeSH terms: Mouth Mucosa/microbiology*
Fulltext Crossover Analysis of the Astringent, Antimicrobial, and Anti-inflammatory Effects of Illicium verum/Star Anise in the Oral Cavity

Assiry AA, Karobari MI, Bhavikatti SK, Marya A

Biomed Res Int, 2021;2021:5510174.
PMID: 34195261 DOI: 10.1155/2021/5510174

Introduction: Illicium verum commonly known as star anise has been widely used in many Asian countries for pharmaceutical treatment for many diseases. The aim of the present study was to investigate the anti-inflammatory, astringent, and antimicrobial properties of an Illicium verum mouthwash.
Methods: The present double blinded randomized clinical trial was conducted on fifty subjects, divided into groups A and B. Illicium verum mouthwash (group A) and placebo (group B) were provided to subjects for 21 days; after 14 days, washout period mouthwashes were switched as per crossover design between groups for 21 days. The gingival index (GI), papillary bleeding index (PBI), and oral microbial count were recorded at each stage of study.
Results: The significant intragroup difference was observed, before crossover in group A and after crossover in group B for GI, PBI, and oral microbial count at different stages of study. On comparing both group A and group B at the first and second follow-up for GI, PBI, and oral microbial count, a statistically significant difference (p < 0.05) was observed. A statistically highly significant mean intergroup and intragroup difference was seen for all the clinical parameters at different stages of study.
Conclusion: The study revealed that the Illicium verum/star anise has potent antibacterial, anti-inflammatory, and astringent properties.

Matched MeSH terms: Mouth Mucosa/microbiology
Induction of suppressor cells following mucosal presentation of Actinomyces viscosus in mice

Sosroseno W, Bird PS, Gemmell E, Seymour GJ

Oral Microbiol. Immunol., 2003 Oct;18(5):318-22.
PMID: 12930525

Mucosal presentation of Actinomyces viscosus results in antigen-specific systemic immune suppression, known as oral tolerance. The aim of the present study was to determine the mechanism by which this oral tolerance is induced. DBA/2 mice were gastrically immunized with A. viscosus. Serum, Peyer's patch (PP) and spleen cells were transferred to syngeneic recipients which were then systemically challenged with the sameiA. viscosus strain. To determine antigen-specificity of cells from gastrically immunized mice, recipients which received immune spleen cells were also challenged with Porphyromonas gingivalis. One week after the last systemic challenge, the delayed type hypersensitivity (DTH) response was determined by footpad swelling and the level of serum IgG, IgA and IgM antibodies to A. viscosus or P. gingivalis measured by an ELISA. No suppression of DTH response or of specific serum antibodies was found in recipients which received serum from gastrically immunized mice. Systemic immune suppression to A. viscosus was observed in recipients which had been transferred with PP cells obtained 2 days but not 4 and 6 days after gastric immunization with A. viscosus. Conversely, suppressed immune response could be seen in recipients transferred with spleen cells obtained 6 days after gastric immunization. The immune response to P. gingivalis remained unaltered in mice transferred with A. viscosus-gastrically immunized cells. The results of the present study suggest that oral tolerance induced by A. viscosus may be mediated by antigen-specific suppressor cells which originate in the PP and then migrate to the spleen.

Matched MeSH terms: Mouth Mucosa/microbiology