Fusobacterium nucleatum induces oxaliplatin resistance by inhibiting ferroptosis through E-cadherin/ß-catenin/GPX4 axis in colorectal cancer.

Fusobacterium (F.) nucleatum is a carcinogenesis microbiota in colorectal cancer (CRC). Growing evidence shows that F. nucleatum contributes to chemoresistance. Ferroptosis is reported to restore the susceptibility of resistant cells to chemotherapy. However, the role of gut microbiota affecting ferroptosis in chemoresistance remains unclear. Here, we examined the CRC tissues of patients using 16S rRNA sequencing to investigate the possible connection between gut microbiota dysbiosis and the relapse of CRC. We found that a high abundance of F. nucleatum in CRC tissue is associated with relapse. We further demonstrated that F. nucleatum induced oxaliplatin resistance in vitro and in vivo. The transcriptome of an F. nucleatum-infected cell revealed ferroptosis was associated with F. nucleatum infection. We perform malondialdehyde, ferrous iron, and glutathione assays to verify the effect of F. nucleatum on ferroptosis under oxaliplatin treatment in vivo and in vitro. Mechanistically, F. nucleatum promoted oxaliplatin resistance by overexpressing GPX4 and then inhibiting ferroptosis. E-cadherin/ß-catenin/TCF4 pathway conducted the GPX4 overexpression effect of F. nucleatum. The chromatin immuno-precipitation quantitative PCR (CHIP-qPCR) and dual-luciferase reporter assay showed that F. nucleatum promoted TCF4 binding with GPX4. We also determined the E-cadherin/ß-catenin/TCF4/GPX4 axis related to tumor tissue F. nucleatum status and CRC relapse clinically. Here, we revealed the contribution of F. nucleatum to oxaliplatin resistance by inhibiting ferroptosis in CRC. Targeting F. nucleatum and ferroptosis will provide valuable insight into chemoresistance management and may improve outcomes for patients with CRC.

The ways Fusobacterium nucleatum translocate to breast tissue and contribute to breast cancer development.

Breast cancer is among the most prevalent malignancies in women worldwide. Epidemiological findings suggested that periodontal diseases may be associated with breast cancer, among which Fusobacterium nucleatum is considered an important cross-participant. In this work, we comprehensively summarize the known mechanisms of how F. nucleatum translocates to, colonizes in mammary tumors, and promotes the carcinogenesis. Specifically, F. nucleatum translocates to mammary tissue through the mammary-intestinal axis, direct nipple contact, and hematogenous transmission. Subsequently, F. nucleatum takes advantage of fusobacterium autotransporter protein 2 to colonize breast cancer and uses virulence factors fusobacterium adhesin A and lipopolysaccharide to promote proliferation. Moreover, the upregulated matrix metalloproteinase-9 induced by F. nucleatum does not only trigger the inflammatory response but also facilitates the tumor-promoting microenvironment. Aside from the pro-inflammatory effect, F. nucleatum may also be engaged in tumor immune evasion, which is achieved through the action of virulence factors on immune checkpoint receptors highly expressed on T cells, natural killer cells, and tumor-infiltrating lymphocytes. Taking breast cancer as an example, more relevant research studies may expand our current knowledge of how oral microbes affect systemic health. Hopefully, exploring these mechanisms in depth could provide new strategies for safer and more effective biologic and targeted therapies targeted at breast cancer.

Fusobacterium nucleatum Promotes Megakaryocyte Maturation in Patients with Gastric Cancer via Inducing the Production of Extracellular Vesicles Containing 14-3-3ε.

Fusobacterium nucleatum colonization contributes to the occurrence of portal vein thrombosis in patients with gastric cancer (GC). However, the underlying mechanism by which F. nucleatum promotes thrombosis remains unclear. In this study, we recruited a total of 91 patients with GC and examined the presence of F. nucleatum in tumor and adjacent non-tumor tissues by fluorescence in situ hybridization and quantitative PCR. Neutrophil extracellular traps (NETs) were detected by immunohistochemistry. Extracellular vesicles (EVs) were extracted from the peripheral blood and proteins in the EVs were identified by mass spectrometry (MS). HL-60 cells differentiated into neutrophils were used to package engineered EVs to imitate the EVs released from NETs. Hematopoietic progenitor cells (HPCs) and K562 cells were used for megakaryocyte (MK) in vitro differentiation and maturation to examine the function of EVs. We observed that F. nucleatum-positive patients had increased NET and platelet counts. EVs from F. nucleatum-positive patients could promote the differentiation and maturation of MKs and had upregulated 14-3-3 proteins, especially 14-3-3ε. 14-3-3ε upregulation promoted MK differentiation and maturation in vitro. HPCs and K562 cells could receive 14-3-3ε from the EVs, which interacted with GP1BA and 14-3-3ζ to trigger PI3K-Akt signaling. In conclusion, we identified for the first time that F. nucleatum infection promotes NET formation, which releases EVs containing 14-3-3ε. These EVs could deliver 14-3-3ε to HPCs and promote their differentiation into MKs via activation of PI3K-Akt signaling.

Study of the inflammatory activating process in the early stage of Fusobacterium nucleatum infected PDLSCs.

Fusobacterium nucleatum (F. nucleatum) is an early pathogenic colonizer in periodontitis, but the host response to infection with this pathogen remains unclear. In this study, we built an F. nucleatum infectious model with human periodontal ligament stem cells (PDLSCs) and showed that F. nucleatum could inhibit proliferation, and facilitate apoptosis, ferroptosis, and inflammatory cytokine production in a dose-dependent manner. The F. nucleatum adhesin FadA acted as a proinflammatory virulence factor and increased the expression of interleukin(IL)-1ß, IL-6 and IL-8. Further study showed that FadA could bind with PEBP1 to activate the Raf1-MAPK and IKK-NF-κB signaling pathways. Time-course RNA-sequencing analyses showed the cascade of gene activation process in PDLSCs with increasing durations of F. nucleatum infection. NFκB1 and NFκB2 upregulated after 3 h of F. nucleatum-infection, and the inflammatory-related genes in the NF-κB signaling pathway were serially elevated with time. Using computational drug repositioning analysis, we predicted and validated that two potential drugs (piperlongumine and fisetin) could attenuate the negative effects of F. nucleatum-infection. Collectively, this study unveils the potential pathogenic mechanisms of F. nucleatum and the host inflammatory response at the early stage of F. nucleatum infection.

Study of the inflammatory activating process in the early stage of Fusobacterium nucleatum infected PDLSCs / 国际口腔科学杂志·英文版

Fusobacterium nucleatum (F. nucleatum) is an early pathogenic colonizer in periodontitis, but the host response to infection with this pathogen remains unclear. In this study, we built an F. nucleatum infectious model with human periodontal ligament stem cells (PDLSCs) and showed that F. nucleatum could inhibit proliferation, and facilitate apoptosis, ferroptosis, and inflammatory cytokine production in a dose-dependent manner. The F. nucleatum adhesin FadA acted as a proinflammatory virulence factor and increased the expression of interleukin(IL)-1β, IL-6 and IL-8. Further study showed that FadA could bind with PEBP1 to activate the Raf1-MAPK and IKK-NF-κB signaling pathways. Time-course RNA-sequencing analyses showed the cascade of gene activation process in PDLSCs with increasing durations of F. nucleatum infection. NFκB1 and NFκB2 upregulated after 3 h of F. nucleatum-infection, and the inflammatory-related genes in the NF-κB signaling pathway were serially elevated with time. Using computational drug repositioning analysis, we predicted and validated that two potential drugs (piperlongumine and fisetin) could attenuate the negative effects of F. nucleatum-infection. Collectively, this study unveils the potential pathogenic mechanisms of F. nucleatum and the host inflammatory response at the early stage of F. nucleatum infection.

Long non-coding RNA EVADR induced by Fusobacterium nucleatum infection promotes colorectal cancer metastasis.

Both Fusobacterium nucleatum (F. nucleatum) and long non-coding RNA (lncRNA) EVADR are associated with colorectal cancer (CRC), but their relationship with CRC metastasis and the mechanisms by which EVADR promotes CRC metastasis are poorly understood. Here, we report that F. nucleatum promotes colorectal cancer cell metastasis to the liver and lung and that it can be detected in CRC-metastasis colonization in mouse models. Furthermore, F. nucleatum upregulates the expression of EVADR, which can increase the metastatic ability of CRC cells in vivo and in vitro. Mechanistically, elevated EVADR serves as a modular scaffold for the Y-box binding protein 1 (YBX1) to directly enhance the translation of epithelial-mesenchymal transition (EMT)-related factors, such as Snail, Slug, and Zeb1. These findings suggest that EVADR induced by F. nucleatum promotes colorectal cancer metastasis through YBX1-dependent translation. The EVADR-YBX1 axis may be useful for the prevention and treatment of patients with F. nucleatum-associated CRC metastasis.

Profiling Fusobacterium infection at high taxonomic resolution reveals lineage-specific correlations in colorectal cancer.

The bacterial genus Fusobacterium promotes colorectal cancer (CRC) development, but an understanding of its precise composition at the species level in the human gut and the relevant association with CRC is lacking. Herein, we devise a Fusobacterium rpoB amplicon sequencing (FrpoB-seq) method that enables the differentiation of Fusobacterium species and certain subspecies in the microbiota. By applying this method to clinical tissue and faecal samples from CRC patients, we detect 62 Fusobacterium species, including 45 that were previously undescribed. We additionally reveal that Fusobacterium species may display different lineage-dependent functions in CRC. Specifically, a lineage (designated L1) including F. nucleatum, F. hwasookii, F. periodonticum and their relatives (rather than any particular species alone) is overabundant in tumour samples and faeces from CRC patients, whereas a non-enriched lineage (designated L5) represented by F. varium and F. ulcerans in tumours has a positive association with lymphovascular invasion.

Fusobacterium nucleatum promotes liver metastasis in colorectal cancer by regulating the hepatic immune niche and altering gut microbiota.

Liver metastasis is the major cause of death in colorectal cancer (CRC) patients. Nevertheless, the underlying mechanisms remain unknown. Gut microbiota intricately affect the initiation and progression of CRC by instigating immune response through the secretion of pro-inflammatory cytokines. In this study, we investigated the contribution of Fusobacterium nucleatum (F.nucleatum) to the microbiota-liver axis of CRC in mice, focusing on the correlation between liver immunity and gut microbiota alterations. When F. nucleatum was orally administered to mice, CRC liver metastasis was evidently exaggerated and accompanied by noticeable deleterious effects on body weight, cecum weight, and overall survival time. Further evaluation of the immune response and cytokine profiles revealed a substantial increase in the levels of pro-inflammatory cytokines such as IL6, IL12, IL9, IL17A, CXCL1, MCP-1, TNF-α, and IFN-γ in the plasma of mice treated with F. nucleatum as compared to that in the untreated control mice. Besides, hepatic immune response was also modulated by recruitment of myeloid-derived suppressor cells, reduction in the infiltration of natural killer (NK) and T helper-17 (Th17) cells, as well as increase in regulatory T cell accumulation in the liver. Additionally, sustained F. nucleatum exposure abridged the murine gut microbiota diversity, inducing an imbalanced and restructured intestinal microflora. In particular, the abundance of CRC-promoting bacteria such as Enterococcus and Escherichia/Shigella was evidently elevated post F. nucleatum treatment. Thus, our findings suggest that F. nucleatum might be an important factor involved in promoting CRC liver metastasis by triggering of liver immunity through the regulation of gut microbiota structure and composition.

Fusobacterium nucleatum promotes colorectal cancer metastasis through miR-1322/CCL20 axis and M2 polarization.

Colorectal cancer (CRC) is one of the most common malignant tumors and is associated with Fusobacterium nucleatum (F. nucleatum, Fn) infection. In this study, we explored the role of F. nucleatum in the CRC metastasis. Our results showed that the abundance of F. nucleatum was enriched in the feces and tumors of patients with CRC and tended to increase in stage IV compared to stage I in patients with metastatic CRC. Tumor-derived CCL20 activated by F. nucleatum not only increases CRC metastasis, but also participates in the reprograming of the tumor microenvironment. F. nucleatum promoted macrophage infiltration through CCL20 activation and simultaneously induced M2 macrophage polarization, enhancing the metastasis of CRC. In addition, we identified using database prediction and luciferase activity hat miR-1322, a candidate regulatory micro-RNA, could bind to CCL20 directly. F. nucleatum infection decreased the expression of miR-1322 by activating the NF-κB signaling pathway in CRC cells. In conclusion, F. nucleatum promotes CRC metastasis through the miR-1322/CCL20 axis and M2 polarization.

The effects of periodontitis associated microbiota on the development of oral squamous cell carcinoma.

Epidemiological data have shown that periodontal bacterial infection, periodontitis, and oral squamous cell carcinoma have close relationship on the disease progress and risk. However, the specific role of periodontal microbes and their mechanism in the development of oral squamous cell carcinoma is not yet clear. In our previous work, metagenomic Illumina Mi-seq analysis was used to identify tstructure and abundance of periodontital microbiome. Accoding to the results, we used Porphyromonas.spp. and Fusobacterium.spp. as the periodontitis positive microbiota; Neisseria.spp and Corynebacterium.spp as periodontitis negative microbiota (their average relative abundance were >5%). These representative strains of the above genus were used to infect OSCC cells to explore their effect on tumor cell biology behavior, and detect the expression level of the gene in related to inflammation, migration, invasion and cell cycle. We find that periodontitis positive correlated microbiota had a promoting effect on the development of oral squamous cell carcinoma in vitro by regulating mRNA and protein expression of IL-6, IL-8, MMP-9 and Cyclin-D1. Periodontitis negative correlated microbiota had suppression effect on the development of oral squamous cell carcinoma in vitro analysis.

Lactobacillus rhamnosus attenuates intestinal inflammation induced by Fusobacterium nucleatum infection by restoring the autophagic flux.

Autophagy plays a dual role in the responses to the gut microflora. The present study aimed to examine the effects of Lactobacillus rhamnosus (L. rhamnosus) on Fusobacterium nucleatum (F. nucleatum)­induced intestinal dysfunction and to elucidate the underlying mechanisms, with particular focus on autophagy. Inflammatory models were established by treatment with L. rhamnosus following F. nucleatum intervention using cells or a mouse model of dextran sulfate sodium (DSS)­induced acute colitis. Autophagosomes were visualized by confocal microscopy following transfection with a tandem GFP­mCherry­LC3 construct and also by transmission electron microscopy. Autophagy­associated protein levels were examined by western blot analysis and immunohistochemistry. It was observed that F. nucleatum induced the production of pro­inflammatory cytokines in Caco­2 cells and aggravated DSS­induced acute colitis. The autophagic flux was impaired following infection with F. nucleatum. L. rhamnosus treatment attenuated the inflammation induced by F. nucleatum infection and effectively recovered the impaired autophagic flux. In addition, the production of pro­inflammatory cytokines induced by F. nucleatum was enhanced with autophagy inhibitors or the RNA interference of autophagy­related gene 16 like 1 (Atg16L1) in Caco­2 cells. Notably, this inhibition of autophagy weakened the effects of L. rhamnosus. Finally, the PI3K/AKT/mTOR pathway was found to be involved in this process. On the whole, the present study demonstrates that the mediation of autophagy by L. rhamnosus may be involved in the protective effects against F. nucleatum­related intestinal inflammation. Thus, L. rhamnosus treatment may prove to be a novel therapeutic strategy for F. nucleatum­realated gut disorders.

Fusobacterium nucleatum in biopsied tissues from colorectal cancer patients and alcohol consumption in Korea.

The roles of individual bacteria and their relationship in the development of colorectal cancer (CRC) remain unclear. We aimed to determine the prevalence of CRC-associated bacteria using quantitative real-time PCR (qPCR) or 16S rRNA analysis and the statistical correlations of patient demographics and clinical characteristics comprising alcohol consumption with CRC-associated bacteria. We determined the prevalence of five CRC-associated bacterial species in 38 CRC patients (39 samples) and 21 normal individuals using qPCR, and the relative abundance of bacterial taxa in the gut microbiome was assessed using 16S rRNA analysis. Fusobacterium nucleatum was the only bacterium that was significantly (P < 0.0001) more prevalent in the cancer tissue (82.1%) than in the normal tissue (0%) by qPCR. 16S rRNA analysis showed a significant correlation between six operational taxonomic units (OTUs), namely, the genera Fusobacterium, Peptostreptococcus, Collinsella, Prevotella, Parvimonas, and Gemella, in patients with CRC. An integrated analysis using 16S rRNA data and epidemiological characteristics showed that alcohol consumption was significantly correlated with the abundance of Fusobacterium OTUs. The correlation of alcohol consumption with the abundance of Fusobacterium OTUs in cancer tissue discovered using 16S rRNA analysis suggests a possible link between alcohol metabolism and subsequent tumorigenesis caused by F. nucleatum.

Fusobacterium nucleatum is associated with worse prognosis in Lauren's diffuse type gastric cancer patients.

Fusobacterium nucleatum (F. nucleatum) is frequently detected in primary colorectal cancer (CRC) and matching metastasis, and has been linked to a worse prognosis. We investigated the presence of F. nucleatum in gastric cancer (GC) and gastric preneoplastic conditions of the stomach, and its potential prognostic value in GC patients. Fusobacterium spp. and F. nucleatum were quantified in various specimens from gastrointestinal tract including paired CRC and GC tissues using probe-based qPCR. Fusobacterium spp. and F. nucleatum were more frequently found in tumorous tissue of CRC and GC compared to non-tumorous tissues. The frequency and bacterial load were higher in CRC compared to GC patients. F. nucleatum positivity showed no association to chronic gastritis or preneoplastic conditions such as intestinal metaplasia. F. nucleatum-positivity was associated with significantly worse overall survival in patients with Lauren's diffuse type, but not with intestinal type GC. There was no association with gender, Helicobacter pylori-status, tumor stage or tumor localization. However, F. nucleatum was positively associated with patient's age and a trend for a lower global long interspersed element-1 DNA methylation. In conclusion, our work provides novel evidence for clinical relevance of F. nucleatum in GC by showing an association between F. nucleatum positivity with worse prognosis of patients with Laurens's diffuse type gastric cancer. Further studies are necessary to explore related mechanistic insights and potential therapeutic benefit of targeted antibiotic treatment in GC patients.

Fusobacterium nucleatum host-cell binding and invasion induces IL-8 and CXCL1 secretion that drives colorectal cancer cell migration.

Fusobacterium nucleatum is implicated in accelerating colorectal cancer (CRC) and is found within metastatic CRC cells in patient biopsies. Here, we found that bacterial invasion of CRC cells and cocultured immune cells induced a differential cytokine secretion that may contribute to CRC metastasis. We used a modified galactose kinase markerless gene deletion approach and found that F. nucleatum invaded cultured HCT116 CRC cells through the bacterial surface adhesin Fap2. In turn, Fap2-dependent invasion induced the secretion of the proinflammatory cytokines IL-8 and CXCL1, which are associated with CRC progression and promoted HCT116 cell migration. Conditioned medium from F. nucleatum-infected HCT116 cells caused naïve cells to migrate, which was blocked by depleting CXCL1 and IL-8 from the conditioned medium. Cytokine secretion from HCT116 cells and cellular migration were attenuated by inhibiting F. nucleatum host-cell binding and entry using galactose sugars, l-arginine, neutralizing membrane protein antibodies, or fap2 deletion. F. nucleatum also induces the mobilization of immune cells in the tumor microenvironment. However, in neutrophils and macrophages, the bacterial-induced secretion of cytokines was Fap2 independent. Thus, our findings show that F. nucleatum both directly and indirectly modulates immune and cancer cell signaling and migration. Because increased IL-8 and CXCL1 production in tumors is associated with increased metastatic potential and cell seeding, poor prognosis, and enhanced recruitment of tumor-associated macrophages and fibroblasts, we propose that inhibition of host-cell binding and invasion, potentially through vaccination or novel galactoside compounds, could be an effective strategy for reducing F. nucleatum-associated CRC metastasis.

Laryngeal chondritis as a differential for upper airway diseases in German sheep.

BACKGROUND: Ovine laryngeal chondritis is a rare entity of sheep in the USA, Great Britain, New Zealand and Iceland, but has not been reported in Germany so far. Here, two German cases are reported. CASE PRESENTATION: Two rams showed severe and progressive signs of dyspnea. Endoscopically, a severe bilateral swelling of the larynx was identified in both rams. Due to poor prognosis and progression of clinical signs one ram was euthanized, while the other ram died overnight. In both cases, a necrosuppurative laryngitis and chondritis of arytenoid cartilages was found at necropsy. Fusobacterium necrophorum and Streptococcus ovis were isolated from the laryngeal lesion in one animal. CONCLUSIONS: This is the first report of ovine laryngeal chondritis in continental Europe. This entity should be considered a differential diagnosis for upper airway disease in sheep.

The impact of the gut microbiota on prognosis after surgery for colorectal cancer - a systematic review and meta-analysis.

The aim of this study was to conduct a systematic review of the association between gut microbiota and prognosis after colorectal cancer surgery. The review was conducted according to the PRISMA guidelines. A systematic literature search was conducted in PubMed, Embase, and Scopus. Studies examining the association between gut microbiota and survival after colorectal cancer surgery were identified. Secondary outcomes were association with cancer stage and immune infiltration of tumor. A total of 27 studies were included in the review. Fusobacterium nucleatum was the most frequently examined bacterium, and the meta-analysis showed that high level of F. nucleatum was significantly associated with decreased overall survival, hazard ratio of 1.63 (95% confidence interval 1.23-2.16) for unadjusted data, and hazard ratio of 1.47 (95% confidence interval 1.08-1.98) for adjusted data. Association between higher tumor stage and F. nucleatum was reported in ten studies, and two studies found an association with unfavorable tumor infiltration of immune cells. Three out of five studies examining Bacteroides fragilis found an association with decreased survival, advanced tumor stage, or unfavorable immune infiltration of tumor. High levels of F. nucleatum and possibly B. fragilis were associated with worse prognosis after surgery for colorectal cancer.

Sites of persistence of Fusobacterium necrophorum and Dichelobacter nodosus: a paradigm shift in understanding the epidemiology of footrot in sheep.

Sites of persistence of bacterial pathogens contribute to disease dynamics of bacterial diseases. Footrot is a globally important bacterial disease that reduces health and productivity of sheep. It is caused by Dichelobacter nodosus, a pathogen apparently highly specialised for feet, while Fusobacterium necrophorum, a secondary pathogen in footrot is reportedly ubiquitous on pasture. Two prospective longitudinal studies were conducted to investigate the persistence of D. nodosus and F. necrophorum in sheep feet, mouths and faeces, and in soil. Molecular tools were used to detect species, strains and communities. In contrast to the existing paradigm, F. necrophorum persisted on footrot diseased feet, and in mouths and faeces; different strains were detected in feet and mouths. D. nodosus persisted in soil and on diseased, but not healthy, feet; similar strains were detected on both healthy and diseased feet of diseased sheep. We conclude that D. nodosus and F. necrophorum depend on sheep for persistence but use different strategies to persist and spread between sheep within and between flocks. Elimination of F. necrophorum would be challenging due to faecal shedding. In contrast D. nodosus could be eliminated if all footrot-affected sheep were removed and fade out of D. nodosus occurred in the environment before re-infection of a foot.

Utilizing Whole Fusobacterium Genomes To Identify, Correct, and Characterize Potential Virulence Protein Families.

Fusobacterium spp. are Gram-negative, anaerobic, opportunistic pathogens involved in multiple diseases, including a link between the oral pathogen Fusobacterium nucleatum and the progression and severity of colorectal cancer. The identification and characterization of virulence factors in the genus Fusobacterium has been greatly hindered by a lack of properly assembled and annotated genomes. Using newly completed genomes from nine strains and seven species of Fusobacterium, we report the identification and corrected annotation of verified and potential virulence factors from the type 5 secreted autotransporter, FadA, and MORN2 protein families, with a focus on the genetically tractable strain F. nucleatum subsp. nucleatum ATCC 23726 and type strain F. nucleatum subsp. nucleatum ATCC 25586. Within the autotransporters, we used sequence similarity networks to identify protein subsets and show a clear differentiation between the prediction of outer membrane adhesins, serine proteases, and proteins with unknown function. These data have identified unique subsets of type 5a autotransporters, which are key proteins associated with virulence in F. nucleatum However, we coupled our bioinformatic data with bacterial binding assays to show that a predicted weakly invasive strain of F. necrophorum that lacks a Fap2 autotransporter adhesin strongly binds human colonocytes. These analyses confirm a gap in our understanding of how autotransporters, MORN2 domain proteins, and FadA adhesins contribute to host interactions and invasion. In summary, we identify candidate virulence genes in Fusobacterium, and caution that experimental validation of host-microbe interactions should complement bioinformatic predictions to increase our understanding of virulence protein contributions in Fusobacterium infections and disease.IMPORTANCEFusobacterium spp. are emerging pathogens that contribute to mammalian and human diseases, including colorectal cancer. Despite a validated connection with disease, few proteins have been characterized that define a direct molecular mechanism for Fusobacterium pathogenesis. We report a comprehensive examination of virulence-associated protein families in multiple Fusobacterium species and show that complete genomes facilitate the correction and identification of multiple, large type 5a secreted autotransporter genes in previously misannotated or fragmented genomes. In addition, we use protein sequence similarity networks and human cell interaction experiments to show that previously predicted noninvasive strains can indeed bind to and potentially invade human cells and that this could be due to the expansion of specific virulence proteins that drive Fusobacterium infections and disease.

Rare isolation of Fusobacterium varium from a case of Fournier's gangrene.

Fusobacterium is a gram negative obligate anaerobic bacilli, a normal inhabitant of gastrointestinal tract, oropharynx and female genital tract. Here we report a case of Fourniers gangrene from which Fusobacterium varium has been isolated along with certain other pathogens. There are only a few reported cases of Fusobacterium varium in literature and it has never been reported from Fournier's gangrene. Through this report we intend to shed some light on the pathogenic potential of anaerobes which are considered as normal flora.