Human colorectal mucosal microbiota correlates with its host niche physiology revealed by endomicroscopy

Immunotherapy strategies and traditional Chinese medicine treatment for microsatellite stable metastatic colorectal cancer

The incidence and mortality of colorectal cancer (CRC) have increased year by year. In addition to traditional radiotherapy, chemotherapy, and targeted therapy, immunotherapy also brings hope to more patients with metastatic colorectal cancer (mCRC). However, these treatments are limited to patients with high microsatellite instability, and about 95% of mCRC patients with microsatellite stability (MSS) can not benefit from them. How to enhance the response of MSS mCRC patients to immunotherapy is the focus of current research. In recent years, it has been found that immunotherapy strategies are expected to improve the clinical efficacy for such patients, and the research reports of TCM combined with immunotherapy are increasing day by day. Therefore, this article aims to review the immunotherapy and traditional Chinese medicine treatment for MSS colorectal cancer.

The human oral - nasopharynx microbiome as a risk screening tool for nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a common head and neck cancer with a poor prognosis. There is an urgent need to develop a simple and convenient screening tool for early detection and risk screening of NPC. 139 microbial samples were collected from 40 healthy people and 39 patients with nasopharyngeal biopsy. A total of 40 and 39 oral, eight and 27 nasal cavity, nine and 16 nasopharyngeal microbial samples were collected from the two sets of individuals. A risk screening tool for NPC was established by 16S rDNA sequencing and random forest. Patients with nasopharyngeal biopsy had significantly lower nasal cavity and nasopharynx microbial diversities than healthy people. The beta diversity of the oral microbiome was significantly different between the two groups. The NPC screening tools based on nasopharyngeal and oral microbiomes have 88% and 77.2% accuracies, respectively. The nasopharyngeal biopsy patients had significantly higher Granulicatella abundance in their oral cavity and lower Pseudomonas and Acinetobacter in the nasopharynx than healthy people. This study established microbiome-based non-invasive, simple, no radiation, and low-cost NPC screening tools. Individuals at a high risk of NPC should be advised to seek further examination, which might improve the early detection of NPC and save public health costs.

Liposome Delivery of Nucleic Acids in Bacteria: Toward In Vivo Labeling of Human Microbiota

Development of specific probes to study the in vivo spatial distribution of microorganisms is essential to understand the ecology of human microbiota. Herein, we assess the possibility of using liposomes loaded with fluorescently labeled nucleic acid mimics (LipoNAMs) to image Gram-negative and Gram-positive bacteria. We proved that liposome fusion efficiencies were similar in both Gram-negative and Gram-positive bacteria but that the efficiency was highly dependent on the lipid concentration. Notably, LipoNAMs were significantly more effective for the internalization of oligonucleotides in bacteria than the fixation/permeabilization methods commonly used in vitro. Furthermore, a structural and morphological assessment of the changes on bacteria allowed us to observe that liposomes increased the permeability of the cell envelope especially in Gram-negative bacteria. Considering the delivery efficiency and permeabilization effect, lipid concentrations of approximately 5 mM should be selected to maximize the detection of bacteria without compromising the bacterial cellular structure.

Oryzanol Attenuates High Fat and Cholesterol Diet-Induced Hyperlipidemia by Regulating the Gut Microbiome and Amino Acid Metabolism

Hyperlipidemia is intricately associated with the dysregulation of gut microbiota and host metabolomes. This study explored the antihyperlipidemic function of oryzanol and investigated whether the function of oryzanol affected the gut microbiome and its related metabolites. Hamsters were fed a standard diet (Control) and a high fat and cholesterol (HFCD) diet with or without oryzanol, separately. Our results showed that oryzanol significantly decreased HFCD-induced fat accumulation, serum total cholesterol, low-density lipoprotein cholesterol (LDL-c), LDL-c/HDL-c ratio, triglyceride, and liver steatohepatitis, attenuated HFCD-induced gut microbiota alterations, and altered amino acid concentrations in feces and the liver. We investigated the role of the gut microbiota in the observed beneficial effects; the protective effects of oryzanol were partly diminished by suppressing the gut bacteria of hamsters after using antibiotics. A fecal microbiota transplantation experiment was carried out by transplanting the feces from HFCD group hamsters or hamsters given oryzanol supplementation (as a donor hamster). Our results showed that administering the fecal liquid from oryzanol-treated hamsters attenuated HFCD-induced hyperlipidemia, significantly decreased the abundance of norank_f__Erysipelotrichaceae, norank_f__Eubacteriaceae, and norank_f__Oscillospiraceae and the concentration of tyrosine. These outcomes are significantly positively correlated with serum lipid concentration. This study illustrated that gut microbiota is the target of oryzanol in the antihyperlipidemic effect.

The Plaque Microbiota Community of Giant Panda (Ailuropoda melanoleuca) Cubs With Dental Caries

Dental caries severely hinders efficient access to adequate energy in wildlife. Different food supplies will develop characteristic plaque, and the microorganisms of these plaque are closely related to dental health. Here, plaque samples from panda cubs with caries and caries-free were collected for 16S rRNA high-throughput sequencing. All sequences clustered into 337 operational taxonomic units (OTUs; 97% identity), representing 268 independent species belonging to 189 genera, 98 families, 51 orders, 24 classes, and 13 phyla. Two groups shared 218 OTUs, indicating the presence of a core plaque microbiome. α diversity analysis showed that the microbial diversity in plaques with caries exceeded that of caries-free. The dominant phyla of plaque microbiota included Proteobacteria, Bacteroidetes, Firmicutes, Fusobacteria, and Actinobacteria. The dominant genera included unclassified Neisseriaceae, Actinobacillus, Lautropia, Neisseria, Porhyromonas, unclassified Pasteurellaceae, Moraxella, Streptococcus, Bergeywlla and Capnocytophaga. β diversity analysis showed that the plaque microbial community structure was different between two groups. Using LEfSe analysis, 19 differentially abundant taxa were identified as potential biomarkers. Finally, function predictions analysis showed All the energy related metabolic pathways on KEGG level 2 were enriched in caries-active group. Consistent with the mainstream caries-causing narrative, our results illuminate the lack of information regarding the oral microflora composition and function within giant panda cubs.

Effect of pH-sensitive nanoparticles on inhibiting oral biofilms

Dental caries is a biofilm-related preventable infectious disease caused by interactions between the oral bacteria and the host’s dietary sugars. As the microenvironments in cariogenic biofilms are often acidic, pH-sensitive drug delivery systems have become innovative materials for dental caries prevention in recent years. In the present study, poly(DMAEMA-co-HEMA) was used as a pH-sensitive carrier to synthesize a chlorhexidine (CHX)-loaded nanomaterial (p(DH)@CHX). In vitro, p(DH)@CHX exhibited good pH sensitivity and a sustained and high CHX release rate in the acidic environment. It also exhibited lower cytotoxicity against human oral keratinocytes (HOKs) compared to free CHX. Besides, compared with free CHX, p(DH)@CHX showed the same antibacterial effects on S. mutans biofilms. In addition, it had no effect on eradicating healthy saliva-derived biofilm, while free CHX exhibited an inhibitory effect. Furthermore, the 16s rDNA sequencing results showed that p(DH)@CHX had the potential to alter oral microbiota composition and possibly reduce caries risk. In conclusion, the present study presents an alternative option to design an intelligent material to prevent and treat dental caries.

Saccharomyces boulardii improves the behaviour and emotions of spastic cerebral palsy rats through the gut-brain axis pathway

BACKGROUND

Cerebral palsy (CP) is a kind of disability that influences motion, and children with CP also exhibit depression-like behaviour. Inflammation has been recognized as a contributor to CP and depression, and some studies suggest that the gut-brain axis may be a contributing factor. Our team observed that Saccharomyces boulardii (S. boulardii) could reduce the inflammatory level of rats with hyperbilirubinemia and improve abnormal behaviour. Both CP and depression are related to inflammation, and probiotics can improve depression by reducing inflammation. Therefore, we hypothesize that S. boulardii may improve the behaviour and emotions of spastic CP rats through the gut-brain axis pathway.

METHODS

Our new rat model was produced by resecting the cortex and subcortical white matter. Seventeen-day-old CP rats were exposed to S. boulardii or vehicle control by gastric gavage for 9 days, and different behavioural domains and general conditions were tested. Inflammation was assessed by measuring the inflammatory markers IL-6 and TNF-α. Hypothalamic-pituitary-adrenal (HPA) axis activity was assessed by measuring adrenocorticotropic hormone and corticosterone in the serum. Changes in the gut microbiome were detected by 16S rRNA.

RESULTS

The hemiplegic spastic CP rats we made with typical spastic paralysis exhibited depression-like behaviour. S. boulardii treatment of hemiplegic spastic CP rats improves behaviour and general conditions and significantly reduces the level of inflammation, decreases HPA axis activity, and increases gut microbiota diversity.

CONCLUSIONS

The model developed in this study mimics a hemiplegic spastic cerebral palsy. Damage to the cortex and subcortical white matter of 17-day-old Sprague-Dawley (SD) rats led to spastic CP-like behaviour, and the rats exhibited symptoms of depression-like behaviour. Our results indicate that S. boulardii might have potential in treating hemiplegic spastic CP rat models or as an add-on therapy via the gut-brain axis pathway.

Metagenomic Analysis Reveals New Microbiota Related to Fiber Digestion in Pigs

Making full use of high fiber and low-cost crop coproducts is helpful to alleviate the situation of people and livestock competing for crops. Digestion of dietary fibers in pigs is mainly through microbial fermentation in the large intestine. To reveal microbiota related to fiber digestion in pigs, fecal samples have been collected from 274 healthy female Suhuai pigs at 160 days of age under the same feeding conditions and have measured apparent neutral detergent fiber (NDF) and acid detergent fiber (ADF) digestibility. Samples from Suhuai pigs with extreme high and low apparent NDF digestibility and extreme high and low apparent ADF digestibility were subjected to shotgun metagenomic sequencing. At the species level, 62 microbial species in H_NDF group and 54 microbial species in H_ADF group were related to high fiber digestibility. Among them, Lachnospiraceae bacterium 3-1 and Alistipes sp. CAG:514 may be new types of microorganisms associated with fiber digestion. In addition, we found that more abundant GH5 and GH48 family (contribute to cellulose degradation) genes, GH39 and GH53 family (contribute to hemicellulose degradation) genes in microorganisms may contribute to the higher apparent NDF digestibility of pigs, and more abundant GH3 and GH9 family (contribute to cellulose degradation) genes in microorganisms may contribute to the higher apparent ADF digestibility of pigs. The abundance of AA4 family (helps in lignin degradation) genes in H_NDF and H_ADF groups was significantly higher than that in L_NDF and L_ADF groups, respectively (P < 0.05). Three pathways in H_NDF group and four pathways in H_ADF group are important pathways associated with degradation of non-starch polysaccharides, and their relative abundance is significantly higher than that in L_NDF and L_ADF groups, respectively. Gut microbiota of Suhuai pigs with high apparent fiber digestibility had higher abundance of genes and microbiota related to fiber digestion and may have stronger fiber digestion potential compared with low apparent fiber digestibility group. This study revealed that the characteristics of gut microbiota and microbial gene functions of pigs with high fiber apparent digestibility, which provided a theoretical basis and reference for further understanding the impact of gut microbiota on fiber digestibility of pigs.

The Clinical Potential of Oral Microbiota as a Screening Tool for Oral Squamous Cell Carcinomas

Introduction

The oral squamous cell carcinoma (OSCC) is detrimental to patients’ physical and mental health. The prognosis of OSCC depends on the early diagnosis of OSCC in large populations.

Objectives

Here, the present study aimed to develop an early diagnostic model based on the relationship between OSCC and oral microbiota.

Methods

Overall, 164 samples were collected from 47 OSCC patients and 48 healthy individuals as controls, including saliva, subgingival plaque, the tumor surface, the control side (healthy mucosa), and tumor tissue. Based on 16S rDNA sequencing, data from all the five sites, and salivary samples only, two machine learning models were developed to diagnose OSCC.

Results

The average diagnostic accuracy rates of five sites and saliva were 98.17% and 95.70%, respectively. Cross-validations showed estimated external prediction accuracies of 96.67% and 93.58%, respectively. The false-negative rate was 0%. Besides, it was shown that OSCC could be diagnosed on any one of the five sites. In this model, Actinobacteria, Fusobacterium, Moraxella, Bacillus, and Veillonella species exhibited strong correlations with OSCC.

Conclusion

This study provided a noninvasive and inexpensive way to diagnose malignancy based on oral microbiota without radiation. Applying machine learning methods in microbiota data to diagnose OSCC constitutes an example of a microbial assistant diagnostic model for other malignancies.

Perturbation of the gut microbiome by Prevotella spp. enhances host susceptibility to mucosal inflammation

Diverse microbial signatures within the intestinal microbiota have been associated with intestinal and systemic inflammatory diseases, but whether these candidate microbes actively modulate host phenotypes or passively expand within the altered microbial ecosystem is frequently not known. Here we demonstrate that colonization of mice with a member of the genus Prevotella, which has been previously associated to colitis in mice, exacerbates intestinal inflammation. Our analysis revealed that Prevotella intestinalis alters composition and function of the ecosystem resulting in a reduction of short-chain fatty acids, specifically acetate, and consequently a decrease in intestinal IL-18 levels during steady state. Supplementation of IL-18 to Prevotella-colonized mice was sufficient to reduce intestinal inflammation. Hence, we conclude that intestinal Prevotella colonization results in metabolic changes in the microbiota, which reduce IL-18 production and consequently exacerbate intestinal inflammation, and potential systemic autoimmunity.

Sequential laxative-probiotic usage for treatment of irritable bowel syndrome: a novel method inspired by mathematical modelling of the microbiome

The gut microbiome plays an important role in human health. However, its response to external intervention is complex. A previous study showed that the response to Clostridium butyricum (CB) treatment of irritable bowel syndrome (IBS) is heterogeneous. We proposed that mathematical model simulation of the microbiota may help to optimize the management of IBS-associated microbiota. In this study, a novel mathematical non-extinction and defecation normalized (NEDN) model was generated for stable simulation of the dynamic nature of gut microbiota. In silico simulation revealed that a laxative may create a favourable opportunity for Clostridium cluster XIVa to shift the microbiota. An explorative clinical trial was conducted to compare three CB regimens in an IBS cohort: laxative, interval of 2 weeks and CB administration for 2 weeks (L2P); laxative immediately followed by CB administration (LP) for 2 weeks; and CB administration for 2 weeks (P). The LP regimen optimally relieved the IBS symptoms and shifted the microbiota closer to those of the healthy subjects during 2 weeks of CB intake. These results indicate that integration of biological/mathematical approaches and clinical scenarios is a promising method for management of microbiota. Additionally, the optimal effect of sequential laxative-CB usage for IBS treatment warrants further validation.

Clinical trial registration numbers: NCT02254629.

Date of registration: October 2, 2014.

Faecal microbiota transplantation from metabolically compromised human donors accelerates osteoarthritis in mice

OBJECTIVES

Emerging evidence suggests that the microbiome plays an important role in the pathogenesis of osteoarthritis (OA). We aimed to test the two-hit model of OA pathogenesis and potentiation in which one 'hit' is provided by an adverse gut microbiome that activates innate immunity; the other 'hit' is underlying joint damage.

METHODS

Medical history, faecal and blood samples were collected from human healthy controls (OA-METS-, n=4), knee OA without metabolic syndrome (OA+METS-, n=7) and knee OA with metabolic syndrome (OA+METS+, n=9). Each group of human faecal samples, whose microbial composition was identified by 16S rRNA sequencing, was pooled and transplanted into germ-free mice 2 weeks prior to meniscal/ligamentous injury (MLI) (n≥6 per group). Eight weeks after MLI, mice were evaluated for histological OA severity and synovitis, systemic inflammation and gut permeability.

RESULTS

Histological OA severity following MLI was minimal in germ-free mice. Compared with the other groups, transplantation with the OA+METS+ microbiome was associated with higher mean systemic concentrations of inflammatory biomarkers (interleukin-1β, interleukin-6 and macrophage inflammatory protein-1α), higher gut permeability and worse OA severity. A greater abundance of Fusobacterium and Faecalibaterium and lesser abundance of Ruminococcaceae in transplanted mice were consistently correlated with OA severity and systemic biomarkers concentrations.

CONCLUSION

The study clearly establishes a direct gut microbiome-OA connection that sets the stage for a new means of exploring OA pathogenesis and potentially new OA therapeutics. Alterations of Fusobacterium, Faecalibaterium and Ruminococcaceae suggest a role of these particular microbes in exacerbating OA.

Antibiotic-induced dysbiosis of the rat oral and gut microbiota and resistance to Salmonella

OBJECTIVES

Antibiotics play a great role in the treatment of infectious diseases, but meantime, they cause great disturbances to host microbiota. Studies on different antibiotic-induced changes in host microbiota are relatively scarce. This study aimed to investigate the changes in oral and gut microbiota and possible alterations of gut resistance to Salmonella induced by the administration of antibiotics.

METHODS

The experiment was conducted by administering antibiotics to rats and detecting oral and gut microbiota by 16S rRNA gene sequencing. In second part, after treating with antibiotics or Lactobacillus rhamnosus the rats were infected by Salmonella Typhimurium and the pathogen burden in the gut was counted by colony forming unit assay.

RESULTS

The gut microbiota underwent dramatic changes after both vancomycin and ampicillin treatment. The alpha diversity sharply decreased, and the microbiota composition showed a significant difference. However, the gut microbiota recovered within four weeks after stopping antibiotics administration, although this recovery was incomplete. Oral microbiota did not show significant alterations in both alpha and beta diversities. The number of pathogens in the gut in the control group was significantly lower than that in the antibiotic-treated group but only lasted for the first 4 days after infection.

CONCLUSIONS

Antibiotics cause dramatic alterations in the number and diversity of gut microbiota but not oral microbiota. These changes in the gut microbiota could incompletely recover four weeks later. When infected with pathogens after antibiotic administration, the rats show a decrease in colonization resistance in the gut for the first four days after infection.

Effect of Novel Micro-Arc Oxidation Implant Material on Preventing Peri-Implantitis

Dental implants occasionally fail for many reasons, especially peri-implantitis. The adhesion of bacteria to the surface of titanium is the initial factor in peri-implantitis. Therefore, the aim of this study was to assess the effect of a novel micro-arc oxidation (MAO) titanium on bacteria inhibition and regulation through periodontitis, and on a healthy saliva-derived biofilm, in vitro. MAO, sandblasting and acid etching (SLA), machined titanium and plasma-sprayed hydroxyapatite (HA) were selected for further study. The metabolic activity and biomass accumulation were tested using MTT (3-(4,5-Dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide) and crystal violet assay after 24 h of anaerobic incubation. The structure was determined by scanning electron microscopy (SEM) and live/dead staining. Moreover, 16S rDNA sequencing was used to assess the microbial community. The results showed that biofilms on MAO were thinner compared to HA and SLA. In the periodontitis group, the biofilm accumulation and metabolic activity reached the highest levels in the HA group (p < 0.05); MAO titanium had the smallest biofilm accumulation and higher live/dead ratio; and the relative abundance of Lactobacillus in the SLA, HA and MAO groups increased significantly compared to the machined group (p < 0.05). In the healthy group, the relative abundance of Lactobacillus in the MAO group increased significantly compared to the other three groups (p < 0.05); the amount and metabolism activity of bacteria in the MAO group was lower (p < 0.05); MAO titanium had the least biofilm accumulation and a higher live/dead ratio. In conclusion, the novel MAO titanium had the ability to combat peri-implantitis by inhibiting the biofilm and regulating the microbial ecosystem to healthier conditions.

Oral bacteria colonize and compete with gut microbiota in gnotobiotic mice

The oral microbiota is associated with oral diseases and digestive systemic diseases. Nevertheless, the causal relationship between them has not been completely elucidated, and colonisation of the gut by oral bacteria is not clear due to the limitations of existing research models. The aim of this study was to develop a human oral microbiota-associated (HOMA) mouse model and to investigate the ecological invasion into the gut. By transplanting human saliva into germ-free (GF) mice, a HOMA mouse model was first constructed. 16S rRNA gene sequencing was used to reveal the biogeography of oral bacteria along the cephalocaudal axis of the digestive tract. In the HOMA mice, 84.78% of the detected genus-level taxa were specific to the donor. Principal component analysis (PCA) revealed that the donor oral microbiota clustered with those of the HOMA mice and were distinct from those of specific pathogen-free (SPF) mice. In HOMA mice, OTU counts decreased from the stomach and small intestine to the distal gut. The distal gut was dominated by Streptococcus, Veillonella, Haemophilus, Fusobacterium, Trichococcus and Actinomyces. HOMA mice and human microbiota-associated (HMA) mice along with the GF mice were then cohoused. Microbial communities of cohoused mice clustered together and were significantly separated from those of HOMA mice and HMA mice. The Source Tracker analysis and network analysis revealed more significant ecological invasion from oral bacteria in the small intestines, compared to the distal gut, of cohoused mice. In conclusion, a HOMA mouse model was successfully established. By overcoming the physical and microbial barrier, oral bacteria colonised the gut and profiled the gut microbiota, especially in the small intestine.

Research on oral microbiota of monozygotic twins with discordant caries experience - in vitro and in vivo study

Oral microbiome is potentially correlated with many diseases, such as dental caries, periodontitis, oral cancer and some systemic diseases. Twin model, as an effective method for studying human microbiota, is widely used in research of relationship between oral microbiota and dental caries. However, there were few researches focusing on caries discordant twins. In this study, in vitro assays were conducted combined with 16S rRNA sequencing analysis on oral microbiota sampled from twins who presented discordant caries experience and mice model was developed as well. Results showed that oral microbiota from caries-active twin possessed higher metabolic activity and produced more lactic production. 16S rRNA sequencing analysis showed that more than 80% of family taxa could be transferred into gnotobiotic-mice. Key caries-associated genera were significantly different between twins and the same difference in genus level could be found in mice as well (p < 0.05). This study suggested that oral microbiota of twins could be distinguished from each other despite the similarities in genetic make-up, living environment, and lifestyle. The difference in microbiota was applied to develop a mice model which may facilitate the investigation of core microbiota of dental caries.

The effect of Clostridium butyricum on symptoms and fecal microbiota in diarrhea-dominant irritable bowel syndrome: a randomized, double-blind, placebo-controlled trial. Sci Rep. 2018;8:2964. [PMID: 29445178 PMCID: PMC5813237 DOI: 10.1038/s41598-018-21241-z]

Irritable bowel syndrome (IBS) is a common disorder in gastrointestinal system and impairs the quality of life of the patients. Clostridium butyricum (CB) is a probiotics that has been used in several gastrointestinal diseases. The efficacy of CB in treating IBS is still unknown. This prospective, multi-centre, randomized, double-blind, placebo-controlled trial aimed to assess the efficacy and safety of CB in treating diarrhea-predominant IBS (IBS-D) and analyze the fecal microbiota after treatment. Two hundred patients with IBS-D were recruited and were given CB or placebo for 4 weeks. End points included change from baseline in IBS symptoms, quality of life, stool consistency and frequency. Compared with placebo, CB is effective in improving the overall IBS-D symptoms (-62.12 ± 74.00 vs. -40.74 ± 63.67, P = 0.038) as well as quality of life (7.232 ± 14.06 vs. 3.159 ± 11.73, P = 0.032) and stool frequency (-1.602 ± 1.416 vs. -1.086 ± 1.644, P = 0.035). The responder rates are found higher in CB compared with the placebo (44.76% vs. 30.53%, P = 0.042). The change in fecal microbiota was analyzed and function pathways of CB in treating IBS-D were predicted. In conclusion, CB improves overall symptoms, quality of life and stool frequency in IBS-D patients and is considered to be used as a probiotics in treating IBS-D clinically.

Anti-Bacteria and Microecosystem-Regulating Effects of Dental Implant Coated with Dimethylaminododecyl Methacrylate

The effects of dimethylaminododecyl methacrylate (DMADDM) modified titanium implants on bacterial activity and microbial ecosystem of saliva-derived biofilm were investigated for the first time. Titanium discs were coated with DMADDM solutions at mass fractions of 0 mg/mL (control), 1, 5 and 10 mg/mL, respectively. Biomass accumulation and metabolic activity of biofilms were tested using crystal violet assay and MTT (3-(4,5-Dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. 16S rRNA gene sequencing was performed to measure the microbial community. Live/dead staining and scanning electron microscopy (SEM) were used to value the structure of biofilm. The results showed that the higher mass fraction of DMADDM the coating solution had, the significantly lower the values of metabolic activity and accumulated biofilms got, as well as fewer live cells and less extracellular matrix. Moreover, 5 mg/mL of DMADDM was the most effective concentration, as well as 10 mg/mL. In microecosystem-regulation, the DMADDM modified titanium implant decreased the relative abundance of Neisseria and Actinomyces and increased the relative abundance of Lactobacillus, a probiotic for peri-implant diseases. In conclusion, via inhibiting growth and regulating microecosystem of biofilm, this novel titanium implant coating with DMADDM was promising in preventing peri-implant disease in an ‘ecological manner’.