Journal of Oral Microbiology最新文献

Background: Antibiotic resistance (AR) is a recognized threat to global human health. However, the prevalence of AR in healthy adults is not well described. The present observational pilot study aimed to uncover the potential of using saliva samples for screening for antibiotic resistance.

Methodology: A laboratory protocol was developed for screening of AR in saliva samples, which was tested and validated using saliva samples collected from 100 study participants. The risk of AR was analyzed with descriptive statistics and evaluated using a risk-factor profile based on information on antibiotic usage within the last 12 months, education level and origin of birth.

Results: AR was identified in 43 (48%) saliva samples, out of which 60,0% and 17,1% of resistant strains displayed resistance to clindamycin and penicillin, respectively. Streptococcus salivarius and Streptococcus parasanguinis were most often identified with AR (51,4% of all cases). The risk of AR was not associated with self-perceived oral or general health, antibiotic use within the latest 12 months or any demographic or socioeconomic parameters recorded. The risk-factor profile was observed in 44% in the AR group versus 30% in the non-AR group (p = 0.19).

Conclusion: The present study showed that it is possible to perform non-invasive saliva-based screening for AR with a frequency of 48% of the samples, highlighting that saliva samples could be a valuable supplement to current surveillance methodologies for AR in the oral microbiota.

Background: The oral microbiome, particularly Fusobacterium nucleatum (Fn), has been implicated in head and neck cancers (HNC), influencing local immunity and Human Papillomavirus (HPV) status. Here, we evaluated the presence of Fn and its association with HPV infection, TERT promoter (TERTp) mutations, and patient outcomes.

Materials and methods: We analyzed 94 formalin-fixed paraffin-embedded (FFPE) tumor tissues from HNC patients previously evaluated for TERTp mutations. Fn DNA was detected using droplet digital PCR (ddPCR), and HPV status was determined via p16 immunohistochemistry in pre-treatment samples. Associations between Fn presence, clinicopathological features, HPV, and TERTp mutation status were assessed.

Results: Tumors primarily originated from the oropharynx (70.2%) and oral cavity (29.8%). Tobacco and alcohol use were reported in 87.2% and 79.8% of cases, respectively. Fn was present in 59.6% of cases, with higher prevalence in oropharyngeal (62.1%) than oral cavity (53.6%) tumors. No significant associations were found between Fn and clinicopathological features, TERTp, or HPV status. However, patients with Fn positivity showed significantly improved cancer-specific survival (61.5% vs. 39.1%, p = 0.013), similar to HPV-positive patients (72.7% vs. 42.7%, p = 0.014).

Conclusion: The presence of Fusobacterium nucleatum in HNC correlates with longer survival, highlighting its potential as a prognostic marker.

Background: Porphyromonas gingivalis (Pg) is a keystone pathogen in periodontitis, encoding a unique peptidyl arginine deiminase (PPAD) linked to protein citrullination, a process associated with rheumatoid arthritis (RA). Recently, we identified a super-active PPAD variant (T2) in Pg isolates. Here, we evaluated if the presence of the super-active T2 variant of PPAD affects the salivary microbiome, the severity of chronic periodontitis (CP), and subsequently CP's causative association with RA onset/progression.

Patients/materials and methods: We examined 56 CP patients and 36 healthy volunteers. Pg and Tannerella forsythia counts were measured via RT-PCR, and PPAD variant was typed via PCR. 16S rRNA from salivary DNA sequencing characterized microbiota composition, while CP severity was assessed through bleeding on probing (BoP), clinical attachment loss (CAL), and pocket depth (PD) parameters.

Results: CP patients exhibited higher Pg and T. forsythia counts, with 30.7% harbouring the PPAD-T2 variant, compared to only one healthy volunteer. Clinical CP parameters were unaffected by the PPAD variant. However, PPAD-T2 influenced oral microbiota composition, enriching certain genera.

Conclusion: While the PPAD variant did not affect CP severity, it influenced oral microbiota composition. Further research is needed to understand citrullination's role in oral microbiota and chronic inflammatory disease development.

Periodontitis has been linked to systemic inflammation, however research on its role in causing systemic diseases remains limited. Recent studies explore probiotics for microbiome modulation and enhancing natural compound bioavailability. This study investigated periodontitis-related systemic disease mechanisms, and evaluated the mitigation effects of bioconversion product using Lactiplantibacillus plantarum SMFM2016-RK and Artemisia herba-alba extracts. Four types of bioconverted milk [BM1 (L. plantarum SMFM2016-RK), BM2 (BM1 + A. herba-alba ethanol extract), BM3 (BM1 + A. herba-alba hot-water extract), and BM4 (BM1+ both A. herba-alba extracts)] were studied in a periodontitis-induced rat model. Rats were divided into six groups: normal control, skim milk with ligature, and four BM groups with ligature.   Periodontitis induction elevated trabecular resorption (0.325 ± 0.057 mm³) and histopathological symptoms. Serum ALT (55.6 ± 6.6 U/L), glucose (261.7 ± 64.3 mg/dL), insulin (1.90 ± 0.87 ng/mL), inflammation in the liver and colon, and gluconeogenesis-related enzyme expression increased. Periodontitis-induced rats showed gut dysbiosis, with decreased Lactobacillaceae level and increased Oscillospiraceae level. BM3 administration significantly reduced the serum glucose (190.9 ± 27.8 mg/dL), ALT (40.5 ± 5.0 U/L), inflammation, and gluconeogenesis-related enzymes, while increasing tight junction proteins expression and phylum Actinobacteria levels in the gut microbiome. The findings highlight the systemic impact of periodontitis on inflammation, glycemic control, and gut microbiome balance. BM3 effectively alleviated these effects suggesting therapeutic potential.

Background: Enterococcus faecalis (E. faecalis), the main pathogenic bacterium of root canal infection, can penetrate deep into the dentin tubule, form a biofilm, and resist host defense mechanisms, thereby increasing treatment complexity. Therefore, the key to the treatment of root canal infections is to completely kill the bacteria and prevent secondary infection. This review assesses advancements in traditional and novel disinfection methods targeting E. faecalis biofilm.

Methods: By comparing the bactericidal mechanisms and effects of the individual and combined application of these methods, the scientific basis and clinical application potential of these methods as adjuvant or alternative treatments were evaluated and the scientific basis for the optimization of the root canal treatment strategy was provided.

Results: Emerging strategies, including natural medicine, antibacterial photodynamic therapy, and cold atmospheric plasma, have shown promising antibacterial effects.

Conclusion: These approaches have the potential to replace traditional disinfection methods, offering more effective solutions for clinical pulp treatment.

Objective: Although Candida species are thought to contribute to dental caries, their acid production under anaerobic conditions and susceptibility to fluoride have not been thoroughly studied. We therefore investigated the growth, acid production, and effect of fluoride on Candida species.

Methods: Aerobic growth, acid production from glucose and its end-products under aerobic and anaerobic conditions, and enolase activity were measured in C. albicans and non-Candida-albicans-Candida (NCAC) species (C. tropicalis, C. parapsilosis, C. maltosa, and C. glabrata), and the effect of fluoride on these abilities was evaluated.

Results: All Candida species produced acids under aerobic and anaerobic conditions, and acetate and TCA cycle metabolites were detected. However, these organic acids only accounted for 1.9-57.6% of the acids produced. Up to 80 mM fluoride hardly inhibited growth and did not inhibit acid production except for C. glabrata, despite the low 50% inhibitory fluoride concentration of 0.19-0.34 mM for enolase.

Conclusion: Candida species produced acids under aerobic and anaerobic conditions, indicating their significant cariogenicity. Their growth and acid production were highly fluoride-resistant, whereas their enolase was fluoride-sensitive, suggesting mechanisms for maintaining low intracellular fluoride. The mechanisms underlying the fluoride resistance remain underexplored. Approaches other than fluoride may be needed to control Candida-associated caries.

Objective: The aim of the present study was to characterize the antimicrobial and anti-inflammatory activities of postbiotics from lactic acid bacteria against Porphyromonas gingivalis.

Material and methods: The anti-P. gingivalis activity of postbiotics from the CERELA culture collection was assessed by measuring changes in the expression of key host proteins by ELISA and qPCR, the proteolytic activity by a fluorescence and a spectrophotometric method and virulence factors from P. gingivalis by qPCR.

Results: Even though Lacticaseibacillus (L.) rhamnosus CRL1522 and Lactiplantibacillus (L.) plantarum CRL1363 exhibit only a discrete antibacterial activity against P. gingivalis, the cell-free supernatants of these strains significantly reduced P. gingivalis-induced secretion of interleukins IL-6 and IL-8 by keratinocytes and TNF-α and IL-6 by U937 macrophage-like cells. More importantly, P. gingivalis arginine-gingipain (Rgp) protease activity was markedly reduced by both lactic acid bacteria (LAB) strains. This finding is particularly interesting because it means that both LAB might prevent the ulterior citrullination of peptides and the consequent generation of autoantibodies. The expression of COX2 and TLR2 was also significantly downregulated in macrophages.

Conclusion: Postbiotics from L. rhamnosus CRL1522 and L. plantarum CRL1363 rise as suitable candidates for antagonizing the periodontopathogen P. gingivalis, since they were able to reduce the expression of proinflammatory cytokines and the protein degradation induced by this pathogen. We propose that postbiotics from these LAB could potentially halt the progression of periodontitis based on this in vitro study.

Background: The oral microbiome of breastfed infants is distinct from that of formula-fed infants. However, breastfeeding characteristics, such as time spent breastfeeding (min/24 h), breastfeeding frequency (number of breastfeeds per day), and human milk intake (ml/day) vary significantly between breastfeeding dyads.

Objectives: Given that human milk and breastfeeding exposures likely influence early colonisation of the infant oral microbiome, this study aimed to elucidate the impact of breastfeeding characteristics on the development of the infant oral microbiome.

Materials and methods: Oral swabs (n = 55) were collected from infants at three months of age, alongside breastfeeding data collected over a 24-hour period. Bacterial DNA profiles were analysed using full-length 16S rRNA gene sequencing.

Results: Variations in breastfeeding characteristics contributed to differences in microbial community structure. Total breastfeeding duration (min/24 h) was positively associated with Bifidobacterium longum and Lactobacillus gasseri, while breastfeeding frequency was negatively associated with Veillonella sp. Additionally, human milk intake (ml/24 h) was negatively associated with Streptococcus parasanguinis.

Conclusion: These findings underscore the significant influence of early life feeding practices on oral microbial communities and emphasise the importance role of breastfeeding in shaping the oral microbiome during early life.

Background: There is no specific cure for periodontitis and treatment is symptomatic, primarily by physical removal of the subgingival plaque biofilm. Current non-surgical periodontal therapy becomes less effective as the periodontal pocket depth increases and as such new adjunctive treatments are required. The development of antibiotic resistance has driven a recent resurgence of interest in bacteriophage therapy.

Methods: Here we review the published literature with a focus on the subgingival phageome, key oral pathobionts and the dysbiotic nature of periodontitis leading to the emergence of synergistic, proteolytic and inflammophilic bacterial species in subgingival plaque. We discuss the opportunities available, the barriers and the steps needed to develop bacteriophage therapy as an adjunctive treatment for periodontitis.

Results: The oral phageome (or virome) is diverse, featuring abundant bacteriophage, that could target key subgingival bacteria. Yet to date few bacteriophages have been isolated and characterised from oral bacterial species, although many more have been predicted by genomic analyses. Bacteriophage therapy has yet to be tested against chronic diseases that are caused by dysbiosis of the endogenous microbial communities.

Conclusion: To be effective as an adjunctive treatment for periodontitis, bacteriophage therapy must cause the collapse of the dysbiotic bacterial community, thereby resolving inflammation and enabling the reestablishment of a health-associated mutualistic subgingival bacterial community. The isolation and characterisation of novel oral bacteriophage is an essential first step in this process.

Objective: Helicobacter pylori (H. pylori) infection affects approximately 50% of the global population. The predominant route of H. pylori transmission is through the oral pathway, making the oral cavity highly significant in its infection. This review focuses on the relationship between H. pylori and oral diseases, the influence of H. pylori infection on the oral microbiota, and the potential mechanisms involving certain oral pathogens.

Method: To identify relevant studies, we conducted searches in PubMed, Google Scholar using keywords such as "Helicobacter pylori," "oral diseases, " "oral microorganisms, " without any date restrictions. The retrieved publications were subject to a review.

Results: H. pylori infection is positively correlated with the occurrence of various oral diseases, such as dental caries, periodontitis, and oral lichen planus. H. pylori may affect the oral microbiota through various mechanisms, and there exists an interactive relationship between H. pylori and oral bacteria, including Streptococcus, Porphyromonas gingivalis (P. gingivalis), and Candida albicans (C. albicans).

Conclusions: H. pylori infection has a close relationship with certain oral diseases. H. pylori modulates oral microflora diversity and structure, while eradication therapy and medications have varying impacts on oral microbiota.