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.

Proteomic characterization of outer membrane vesicles from gut mucosa-derived fusobacterium nucleatum

Fusobacterium nucleatum is a Gram-negative bacterium commonly found in the oral cavity and is often involved in periodontal diseases. Recent studies have shown increased F. nucleatum prevalence in colorectal cancer (CRC) tissues, and causal data has linked this bacterium to CRC tumorigenesis. Immune-based approaches to contain, reduce or eradicate its gut colonization may prevent CRC. Outer membrane vesicles (OMVs) are naturally produced by Gram-negative bacteria, typically contain multiple putative virulence factors and may elicit protective immune responses if used as vaccines. Here, OMVs were isolated from F. nucleatum cultures and purified using gradient centrifugation. Proteins contained within the OMVs were identified by nano LC/MS/MS analysis. Of 98 proteins consistently identified from duplicate analyses, 60 were predicted to localize to the outer membrane or periplasm via signal peptide driven translocation. Of these, six autotransporter proteins, which constitute the majority of protein mass of OMVs, were associated with Type V secretion system. In addition, other putative virulence factor proteins with functional domains, including FadA, MORN2 and YadA-like domain, were identified with multiple exposed epitope sites as determined by in silico analysis. Altogether, the non-replicative OMVs of F. nucleatum contain multiple antigenic virulence factors that may play important roles in the design and development of vaccines against F. nucleatum. SIGNIFICANCE: Fusobacterium nulceatum has been proved playing significant role in colorectal carcinogenesis. Outer membrane vesicles are nanoparticles that naturally secreted by Gram-negative bacterial containing various antigenic components, which provides new insight in vaccine development. Understanding the constituents of F. nucleatum OMVs will provide fundamental information and potential strategies for OMV-based F. nucleatum vaccines design. Based on our knowledge this is the first proteomic study of OMVs from F. nucleatum.

Fusobacterium nucleatum-Induced Impairment of Autophagic Flux Enhances the Expression of Proinflammatory Cytokines via ROS in Caco-2 Cells

Fusobacterium nucleatum (F. nucleatum) plays a critical role in gastrointestinal inflammation. However, the exact mechanism by which F. nucleatum contributes to inflammation is unclear. In the present study, it was revealed that F. nucleatum could induce the production of proinflammatory cytokines (IL-8, IL-1β and TNF-α) and reactive oxygen species (ROS) in Caco-2 colorectal) adenocarcinoma cells. Furthermore, ROS scavengers (NAC or Tiron) could decrease the production of proinflammatory cytokines during F. nucleatum infection. In addition, we observed that autophagy is impaired in Caco-2 cells after F. nucleatum infection. The production of proinflammatory cytokines and ROS induced by F. nucleatum was enhanced with either autophagy pharmacologic inhibitors (3-methyladenine, bafilomycin A1) or RNA interference in essential autophagy genes (ATG5 or ATG12) in Caco-2 cells. Taken together, these results indicate that F. nucleatum-induced impairment of autophagic flux enhances the expression of proinflammatory cytokines via ROS in Caco-2 Cells.

[Sepsis due to fusobacteria in a young adult]

Fusobacteria belong to the normal population of the pharyngeal mucosa as well as the mucosa of the upper airways and the gastrointestinal tract. Infections are comparatively rare. The most common causative organism is Fusobacterium necrophorum. A well-known infection caused by this germ is Lemierre's syndrome. In the presented case, a 19-year-old man (123 kg body weight, 186 cm body length) was found dead in his bed in the morning after having complained of muscular fatigue and vomiting the previous day. Autopsy was carried out only two days after death. At that time, the body showed marked putrefaction with partial greenish discoloration and marbling of the skin although it had been stored in a refrigerator at +2 degrees C in the meantime. While the autopsy itself revealed no cause of death, microbiological examination of a smear from the left lower pulmonary lobe demonstrated Staphylococcus aureus and Fusobacterium necrophorum. Toxicological investigations produced negative results throughout. The cause of death was defined as sepsis caused by Fusobacterium necrophorum.

Fusobacterium in colonic flora and molecular features of colorectal carcinoma

Fusobacterium species are part of the gut microbiome in humans. Recent studies have identified overrepresentation of Fusobacterium in colorectal cancer tissues, but it is not yet clear whether this is pathogenic or simply an epiphenomenon. In this study, we evaluated the relationship between Fusobacterium status and molecular features in colorectal cancers through quantitative real-time PCR in 149 colorectal cancer tissues, 89 adjacent normal appearing mucosae and 72 colonic mucosae from cancer-free individuals. Results were correlated with CpG island methylator phenotype (CIMP) status, microsatellite instability (MSI), and mutations in BRAF, KRAS, TP53, CHD7, and CHD8. Whole-exome capture sequencing data were also available in 11 cases. Fusobacterium was detectable in 111 of 149 (74%) colorectal cancer tissues and heavily enriched in 9% (14/149) of the cases. As expected, Fusobacterium was also detected in normal appearing mucosae from both cancer and cancer-free individuals, but the amount of bacteria was much lower compared with colorectal cancer tissues (a mean of 250-fold lower for Pan-fusobacterium). We found the Fusobacterium-high colorectal cancer group (FB-high) to be associated with CIMP positivity (P = 0.001), TP53 wild-type (P = 0.015), hMLH1 methylation positivity (P = 0.0028), MSI (P = 0.018), and CHD7/8 mutation positivity (P = 0.002). Among the 11 cases where whole-exome sequencing data were available, two that were FB-high cases also had the highest number of somatic mutations (a mean of 736 per case in FB-high vs. 225 per case in all others). Taken together, our findings show that Fusobacterium enrichment is associated with specific molecular subsets of colorectal cancers, offering support for a pathogenic role in colorectal cancer for this gut microbiome component.

Fusobacterium in colonic flora and molecular features of colorectal carcinoma

Fusobacterium species are part of the gut microbiome in humans. Recent studies have identified overrepresentation of Fusobacterium in colorectal cancer tissues, but it is not yet clear whether this is pathogenic or simply an epiphenomenon. In this study, we evaluated the relationship between Fusobacterium status and molecular features in colorectal cancers through quantitative real-time PCR in 149 colorectal cancer tissues, 89 adjacent normal appearing mucosae and 72 colonic mucosae from cancer-free individuals. Results were correlated with CpG island methylator phenotype (CIMP) status, microsatellite instability (MSI), and mutations in BRAF, KRAS, TP53, CHD7, and CHD8. Whole-exome capture sequencing data were also available in 11 cases. Fusobacterium was detectable in 111 of 149 (74%) colorectal cancer tissues and heavily enriched in 9% (14/149) of the cases. As expected, Fusobacterium was also detected in normal appearing mucosae from both cancer and cancer-free individuals, but the amount of bacteria was much lower compared with colorectal cancer tissues (a mean of 250-fold lower for Pan-fusobacterium). We found the Fusobacterium-high colorectal cancer group (FB-high) to be associated with CIMP positivity (P = 0.001), TP53 wild-type (P = 0.015), hMLH1 methylation positivity (P = 0.0028), MSI (P = 0.018), and CHD7/8 mutation positivity (P = 0.002). Among the 11 cases where whole-exome sequencing data were available, two that were FB-high cases also had the highest number of somatic mutations (a mean of 736 per case in FB-high vs. 225 per case in all others). Taken together, our findings show that Fusobacterium enrichment is associated with specific molecular subsets of colorectal cancers, offering support for a pathogenic role in colorectal cancer for this gut microbiome component.

Similar recovery rates of Fusobacterium necrophorum from recurrently infected and non-infected tonsils

INTRODUCTION

Recent studies implicate the presence of Fusobacterium necrophorum (FN) in recurrent tonsillitis (RT), acute tonsillitis and peritonsillar abscess. The objective of the present study was to determine whether FN plays a role in RT by comparing bacteriologic results from patients suffering from RT, tonsillar hypertrophy and halitosis or persistent sore throat syndrome (PSTS). We analyzed both tonsils to determine the degree of concordance.

MATERIAL AND METHODS

A prospective study was conducted in 80 patients aged 8-30 years who were undergoing elective tonsillectomy. The patients were divided into four groups according to indication for surgery. Aerobic and anaerobic cultures from the tonsillar surface and core were analyzed.

RESULTS

FN was detected less frequently in the tonsillar cores of RT patients (22%) than in those of patients without RT (30%) (p=0.44). FN detection frequencies ranged between 20% and 35% across the four groups. Betahaemolytic streptococci groups A/C/G (BHS) were detected significantly (p=0.007) more often in the RT group than in the halitosis/PSTS group.

CONCLUSION

A possible role of FN in RT was not substantiated. Our results indicate that FN is likely to be part of the normal flora. The tonsillar surface and core flora carry considerable interpersonal diversity, but is very similar bilaterally in each individual. Other factors seem to play a major role in the development of the represented tonsillar diseases.

FUNDING

Not relevant.

TRIAL REGISTRATION

The study was approved by The Research Ethics Committee of Aarhus County (no. 20050034).

A case of pyogenic liver abscess infected with Fusobacterium necrophorum depicted by microscopy and confirmed by tissue culture

A 40-year-old man was admitted with a continuous high grade fever accompanying a relatively large solitary liver abscess with septations. A puncture of the abscess revealed gram-negative rods that could be identified histologically as Fusobacterium necrophorum, which was later confirmed by tissue culture. The patient was switched to meropenem and penicillin, and cured of the infection. Fusobacterium necrophorum is a rare bacterium causing potentially fatal liver abscesses in humans. Clinicians should bear Fusobacterium necrophorum in mind when treating patients with an enlarged solitary liver abscess.

Fusobacterium necrophorum bacteremic tonsillitis: 2 Cases and a review of the literature

Fusobacterium necrophorum can cause endemic pharyngitis and the Lemierre syndrome. Four previous case reports and one epidemiologic study have documented that some F. necrophorum pharyngitis patients develop bacteremia without developing the complete Lemierre syndrome. We report two more patients who have bacteremic F. necrophorum pharyngitis. We summarize the clinical presentation of these six patients. All received early diagnosis and excellent response to antibiotics. We speculate that prompt antibiotic treatment may have prevented the more serious Lemierre syndrome. Adolescents and young adults who present with significant pharyngotonsillitis and bacteremic symptoms should have blood cultures and receive antibiotic regimens that treat F. necrophorum. Recognition of such patients might prevent Lemierre syndrome.

Digital necrobacillosis in Norwegian wild tundra reindeer (Rangifer tarandus tarandus)

Outbreaks of digital necrobacillosis in Norwegian wild tundra reindeer (Rangifer tarandus tarandus) are described. The outbreaks occurred in late summer and autumn 2007 and 2008, subsequent to periods with an unusually high number of days with precipitation and high air temperature. Lesions were generally restricted to one foot and the disease incidence was highest in calves. Single limbs from 20 animals and six whole carcasses were submitted for laboratory examination. Gross lesions were characterized by swelling of the fetlock to coronary band area and cutaneous sinus tracts with sparse discharge of pus. Subcutaneous tissue was inflamed and oedematous with focal necrosis. Tendons, tendon sheaths, joints and periosteum of the digital bones were often affected. Animals shot during winter showed severe chronic periostitis and osteomyelitis and necrotizing deforming arthritis. Microscopically, skin lesions were characterized by deep ulcers with centrally located necrotic tissue, bordered by a zone of oedema and intense inflammation with granulation tissue and fibrosis. Necrosis, suppurative inflammation and oedema were found in the synovial membranes, tendons and tendon sheaths. Digital bone lesions were characterized by necrosis, fibrosis and extensive bone proliferation. Vasculitis and thrombosis were common in all lesions. Elongate filamentous gram-negative bacteria in necrotic lesions from all animals were identified as Fusobacterium necrophorum by fluorescence in-situ hybridization. F. necrophorum was cultured from the foot lesions of six animals. Five of these isolates were examined by 16S rRNA sequencing. The sequences were identical and differed from all other strains listed in GenBank. These results are consistent with circulation of a reindeer-adapted pathogenic strain of F. necrophorum in the wild reindeer population, causing outbreaks of digital necrobacillosis following warm and humid summers.

Lemierre syndrome from an odontogenic source: a review for dentists

Lemierre syndrome, which can result from a recent oropharyngeal or odontogenic infection, is characterized by clinical or radiographic signs of thrombosis of the internal jugular vein, distant infected emboli and the presence of anaerobic pathogens, usually Fusobacterium necrophorum. The septic emboli resulting from the infected thrombophlebitis of the internal jugular vein give the syndrome its constellation of central nervous system, pulmonary and many other manifestations including septic shock. This condition was so rare that, historically, it became known as the "forgotten disease," but an increasing frequency of reports indicates that Lemierre syndrome may not be so uncommon.

Differential activation of NF-kappaB and gene expression in oral epithelial cells by periodontal pathogens

To investigate the molecular effects of the periodontopathogens Fusobacterium nucleatum (FN) and Porphyromonas gingivalis (PG) on the oral epithelium, the H400 oral epithelial cell line was cultured in the presence of non-viable bacteria. Following confirmation of the presence of transcripts for the bacterial pattern recognition receptors in H400 cells, Toll-like receptors -2, -4 and -9, and components of the NF-kappaB signalling pathway, immunocytochemical analyses were performed showing that NF-kappaB was activated within 1 h of exposure to both periodontopathogens. A significantly greater number of NF-kappaB nuclear translocations were apparent following H400 cell exposure to FN as compared with PG. Gene expression analyses indicated that transcripts known to be regulated by the NF-kappaB pathway, including cytokines/chemokines TNF-alpha, IL-1beta, IL-8, MCP-1/CCL2 and GM-CSF, were up-regulated following 4 and 24 h of exposure to both periodontopathogens. In addition, H400 periodontopathogen exposure resulted in differential regulation of transcripts for several cytokeratin gene family members. Consistent with the immunocytochemical data, microarray results indicated that FN induced a greater number of gene expression changes than PG following 24 h of exposure, 609 and 409 genes, respectively. Ninety-one genes were commonly differentially expressed by both periodontopathogens and represented biological processes commonly associated with periodontitis. Gene expression analyses by reserve transcriptase-polymerase chain reaction (RT-PCR) of molecules identified from the microarray data sets, including Heme oxygenase-1, lysyl oxidase, SOD2, CCL20 and calprotectin components, confirmed their differential expression profiles induced by the two periodontopathogens. FN and PG have clearly different molecular effects on oral epithelial cells, potentially highlighting the importance of the composition of the plaque biofilm in periodontitis pathogenesis.

Clinical characteristics of fusobacterial brain abscess

We retrospectively reviewed 122 patients with culture-proven bacterial brain abscesses (BBA) at our hospital over a period of 20 years and identified seven fusobacterial brain abscess patients. Here we describe the therapeutic experience in fusobacterial BBA cases and compare the clinical features of patients with single pathogen infection between fusobacterial and non-fusobacterial brain abscesses. Fusobacterium spp. accounted for 6% of the implicated pathogens of monomicrobial BBA. All seven fusobacterial brain abscess patients contracted the infection spontaneously, and two cases had important preceding events. F. nucleatum was the commonest one of the species described. Clinical presentations and laboratory data of these seven patients were similar to those of non-fusobacterial BBA, and in these patients the diagnosis was only confirmed by positive culture results. All seven patients were successfully treated with combined surgical and antimicrobial therapy. Although the average age tends to be older and there is a higher prevalence of multiloculated brain abscesses in patients with this type of BBA, the therapeutic outcome can be favorable with early diagnosis and prompt treatment.

Effects of a collagenolytic cell wall component from Fusobacterium necrophorum subsp. necrophorum on rabbit tissue-culture cells

The effects on rabbit tissue-cultured cells of collagenolytic cell wall component (CCWC) from Fusobacterium necrophorum subsp. necrophorum were investigated. Scanning electron microscopy demonstrated that CCWC damaged the cell surfaces of the rabbit granulocytes and hepatocytes but the effects of the cells differed from each other. Granulocytes appeared smooth and morphologically irregular whereas hepatocytes looked rough and had tiny holes in the cell membranes. Differences in cell viability were observed in MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulphophenyl)-2H-tetrazolium, inner salt) assay. The findings suggest that cytotoxic activity in vivo may well contribute to the establishment of an initial injury in visceral tissues, and the action of CCWC could increase the chances of survival for an invading F. necrophorum subsp. necrophorum at the first stages of infection.

Lemierre’s syndrome

We report a case of Lemierre’s syndrome complicated by an epidural abscess. This manifestation of Lemierre’s syndrome has not been described previously.

Enhanced pathogenicity of Fusobacterium nucleatum adapted to oxidative stress

Fusobacterium nucleatum is an obligate anaerobic bacterium found in the indigenous human microbiota but also recovered from several anaerobic infections. Considering the biological and medical relevance of F. nucleatum, the characterization of its response to oxidative stress is needed in order to understand how this anaerobic bacterium survives during an invasive process of oxygenated tissues. Influence of oxidative stress by atmospheric oxygen exposure on cellular morphology and pathogenicity of F. nucleatum were investigated. The wild-type F. nucleatum ATCC 25586 (wt-strain) was exposed to oxidative stress to select an adapted strain (aero-strain). Conventional NIH Swiss mice were split in two experimental groups which were challenged intraperitoneally with wt-strain and aero-strain, respectively, and a control group, unchallenged. Histopathological and hyperemia analysis were performed by day 30 after infection. Gram stain of aero-strain showed drastic changes in cellular morphology when compared to wt-strain. A significant increase of liver weight/body weight ratio (P < 0.05) as well as a tendency (P = 0.16) to higher spleen weight/body weight ratio were observed for the mice challenged with aero-strain when compared to the two other animal groups. Additionally, these animals also showed hyperemia in the spleen and liver as well as an increased number of inflammatory cells and steatosis in the liver. The results showed that, in addition to extensive changes in cell morphology, the adaptation to oxidative stress might also influence the pathogenicity of F. nucleatum. These findings have clinical implications since in the host tissues this indigenous putative pathogen is exposed to more or less oxygenated environments found on the different anatomic sites invaded by the bacterium.

Fibrinonecrotic rhinitis caused by a concurrent infection of Fusobacterium necrophorum and Arcanobacterium pyogenes in a cow

An 8 year-old cow showing severe dyspnea and nasal mucosal necrosis immediately after parturition was subjected to pathological examination. The principal lesions were fibrinonecrotic rhinitis, necrotic bronchopneumonia and renal infarction. Fusobacterium necrophorum biotype A and Arcanobacterium pyogenes antigens were detected in the nasal and pulmonary lesions. These results suggest that the lesions were caused by a concurrent infection of the detected bacteria and that the pulmonary lesions were caused by the aspiration of infectious materials from the nasal ones. Mucosal coagulative necroses observed as the initial lesions in rhinitis were frequently associated with multiple thrombosis. The findings might suggest that thrombosis played an important role in the development of the nasal lesions.

Nécrobacillose et syndrome de Lemierre : à propos d’un cas

Necrobacillosis (Fusobacterium necrophorum septicaemia) and Lemierre's syndrome (human necrobacillosis with cephalic origin) are not widely known by clinicians.

CASE REPORT

We report the case of a 5-year-old girl, presenting with a Lemierre's syndrome consecutive to otitis media. Outcome was favourable under metronidazole and amoxicilline therapy for 6 weeks.

CONCLUSION

Necrobacillosis remains a severe disease including peripheral abscesses (mainly in the lungs and the liver), often associated with thrombosis of the internal jugular vein in case of Lemierre's syndrome. Prolonged metronidazole and amoxicilline antibiotherapy allows nowadays a healthy outcome.

Liver abscesses due to Fusobacterium spp that mimick malignant metastatic liver disease

A 71-year-old man presented with the clinical and radiological features of metastatic liver disease but subsequently was found to have multiple liver abscesses caused by Fusobacterium necrophorum. At liver biopsy, pus was aspirated and Fusobacterium necrophorum was isolated from the pus. Serial blood cultures and urine cultures were sterile and negative for Fusobacterium spp. The patient made a complete recovery in response to treatment with penicillin and amoxicillin. This case illustrates the importance of liver abscesses as an uncommon but completely treatable differential diagnosis for the radiological appearances of multiple hepatic lesions.

Mice lacking monocyte chemoattractant protein 1 have enhanced susceptibility to an interstitial polymicrobial infection due to impaired monocyte recruitment

Monocyte chemoattractant protein 1 (MCP-1) is an important chemokine that induces monocyte recruitment in a number of different pathologies, including infection. To investigate the role of MCP-1 in protecting a host from a chronic interstitial polymicrobial infection, dental pulps of MCP-1(-/-) mice and controls were inoculated with six different oral pathogens. In this model the recruitment of leukocytes and the impact of a genetic deletion on the susceptibility to infection can be accurately assessed by measuring the progression of soft tissue necrosis and osteolytic lesion formation. The absence of MCP-1 significantly impaired the recruitment of monocytes, which at later time points was threefold higher in the wild-type mice than in MCP-1(-/-) mice (P < 0.05). The consequence was significantly enhanced rates of soft tissue necrosis and bone resorption (P < 0.05). We also determined that the MCP-1(-/-) mice were able to recruit polymorphonuclear leukocytes (PMNs) to a similar or greater extent as controls and to produce equivalent levels of Porphyromonas gingivalis-specific total immunoglobulin G (IgG) and IgG1. These results point to the importance of MCP-1 expression and monocyte recruitment in antibacterial defense and demonstrate that antibacterial defense is not due to an indirect effect on PMN recruitment or modulation of the adaptive immune response.

Immunohistochemical and ultrastructural identification of Fusobacterium necrophorum subsp. necrophorum in bovine fatal necrotizing glossitis

A 37-day-old male Japanese black calf showing marked salivation and leucocytosis died and was examined the tissues histologically. Histological lesions were characterized by severe focal necrotic glossitis on the ventral side of the root of the tongue. Immunohistochemically, Fusobacterium necrophorum subsp. necrophorum antigen was detected in the necrotic tissues and its distribution corresponded to that of the gram-negative, nonsporeforming, long filamentous organisms. Ultrastructural similarities between the organism and F. necrophorum subsp. necrophorum, but not subsp. funduliforme were observed. These findings clearly demonstrated that the fatal necrotic glossitis was caused by F. necrophorum subsp. necrophorum. This is the first report of bovine fatal necrotizing glossitis with leucocytosis caused by F. necrophorum subsp. necrophorum infection, and this organism may be an important fatal pathogen in calves with glossal lesions.

[Clinical and microbiological study of adult periodontal disease]

The aim of this study was to carry out a microbiological evaluation of sites with and without clinical evidence of moderate and severe periodontitis and their correlation with clinical parameters. A total of 52 disease sites and 10 healthy sites were selected according to clinical criteria. The following clinical indexes were measured for all the sites: plaque index, gingival index, blood on probing, depth on probing and insertion level. Samples of subgingival plaque were collected for culture and for differential counts of microbial morphotypes. In disease sites the most frequently isolated were: Prevotella intermedia/nigrescens (65%), Porphyromonas gingivalis (23%), Actinobacillus actinomycetemcomitans (23%), Fusobacterium nucleatum (10%) and Peptostreptococcus sp. (31%). The aerobic gram-positive microflora was predominant in healthy sites. Significant differences were observed in microbial morphotypes between healthy and disease sites: cocci 18.71% and 78.90%, motile rods 46.12% and 16.70%, total spirochetes 26.48% and 2.80%, respectively. The presence of motile rods, spirochetes and P. intermedia/nigrescens were the parameters with most sensitivity to suspect periodontal disease. There were significant differences in the subgingival microflora between healthy and disease sites in patients with moderate and severe periodontitis.

Bone resorption caused by three periodontal pathogens in vivo in mice is mediated in part by prostaglandin

Gingival inflammation, bacterial infection, alveolar bone destruction, and subsequent tooth loss are characteristic features of periodontal disease, but the precise mechanisms of bone loss are poorly understood. Most animal models of the disease require injury to gingival tissues or teeth, and the effects of microorganisms are thus complicated by host responses to tissue destruction. To determine whether three putative periodontal pathogens, Porphyromonas gingivalis, Campylobacter rectus, and Fusobacterium nucleatum, could cause localized bone resorption in vivo in the absence of tissue injury, we injected live or heat-killed preparations of these microorganisms into the subcutaneous tissues overlying the calvaria of normal mice once daily for 6 days and then examined the bones histologically. We found that all three microorganisms (both live and heat killed) stimulated bone resorption and that the strain of F. nucleatum used appeared to be the strongest inducer of osteoclast activity. Treatment of the mice concomitantly with indomethacin reduced but did not completely inhibit bone resorption by these microorganisms, suggesting that their effects were mediated, in part, by arachidonic acid metabolites (e.g., prostaglandins). Our findings indicate that these potential pathogens can stimulate bone resorption locally when placed beside a bone surface in vivo in the absence of prior tissue injury and support a role for them in the pathogenesis of bone loss around teeth in periodontitis.

Case report: necrotic glossitis and sinusitis in a cow caused apparently by a Fusobacterium necrophorum like microorganism

An unusual case of necrotic infection of the tongue and unilateral necrotic maxillar sinusitis, in a cow is reported. The prominent clinical findings were: a marked salivation, unilateral mucopurulent nasal discharge, diffuse necrotic lesions on the ventral side of the tongue and fetid breath. Clinico-pathological and pathological findings and abnormalities in the haemogram were probably caused by the toxins produced by the causative organism--Fusobacterium necrophorum like microorganism.

Selecting therapy for serious infections in children: maximizing safety and efficacy

Serious infections in children represent unique challenges for the treating physician. For the pediatric patient, considerations of drug toxicity are especially critical to avoid potential long-term complications of therapy. There are several advantages associated with using single, broad-spectrum, empiric antibiotic therapy, including reduced potential for drug-mediated toxicity or drug interactions and facilitation of home therapy. Of the antibiotics available for monotherapy, the carbapenems have the broadest spectrum of activity. However, a major obstacle toward the use of the carbapenems in pediatrics has been the risk of seizures occurring during therapy with imipenem/cilastatin. In clinical studies of meningitis and other infections in children, no drug-related seizures were reported when treated with the carbapenem meropenem. Meropenem monotherapy has been shown to be similar to ceftriaxone- and cefotaxime-based single or multiple antibiotic regimens, in terms of clinical and microbiologic efficacy and tolerability. Thus, meropenem represents a favorable treatment choice for the seriously ill child, either as empiric monotherapy or as definitive therapy of polymicrobial or nosocomial infections.

Host modulation of tissue destruction caused by periodontopathogens: effects on a mixed microbial infection composed of Porphyromonas gingivalis and Fusobacterium nucleatum

These studies determined the ability of selected periodontopathogens to synergistically initiate soft tissue destruction in a murine abscess model. The development of immunity following recovery from infection or by active immunization was also examined. Mice were infected with P. gingivalis W50, F. nucleatum T18, or a combination of the two microorganisms. F. nucleatum caused only a localized lesion in contrast to P. gingivalis which caused a spreading suppurative inflammatory lesion of the skin and subcutaneous tissues, which, depending upon the dose, could result in death. Infection of mice with a combination of P. gingivalis and F. nucleatum elicited a significantly greater lesion size (P<0.001) and lethality compared with P. gingivalis alone. Mice infected with a subclinical dose (no visible lesion) of P. gingivalis failed to develop protective immunity to a secondary P. gingivalis challenge. Mice that had recovered from P. gingivalis lesions demonstrated partial protection against subsequent P. gingivalis challenge; however, the immunity was less protective against the mixed F. nucleatum + P. gingivalis infection. Active immunization with P. gingivalis protected against both the P. gingivalis and F. nucleatum + P. gingivalis challenges and this protection was correlated with the levels of specific serum immunoglobulin G (IgG) antibody. The results indicated that the murine model is ideally suited to examine bacterially-mediated mixed infections that result in soft tissue destruction. This destruction can be minimized, but not abrogated, with development of immunity. Challenge with sufficient numbers of the pathogens can overwhelm the acquired immunity.

Mixed infection with Porphyromonas gingivalis and Fusobacterium nucleatum in a murine lesion model: potential synergistic effects on virulence

These studies determined the characteristics of tissue destruction in a murine abscess model elicited by mixed infection with the periodontopathogens Fusobacterium nucleatum and Porphyromonas gingivalis. The interbacterial effects of this synergism, the kinetics of the relationship of the bacterial interaction, and the characteristics of the bacteria required for the tissue destruction were studied. Infection of mice with P. gingivalis and F. nucleatum strains elicited lesions of various sizes as a function of infective dose. Primary infection with F. nucleatum plus P. gingivalis at various ratios (i.e., <1:1) resulted in a significantly greater lesion size (P < 0.001) compared with that resulting from primary infection with P. gingivalis alone. At F. nucleatum/P. gingivalis ratios of > or = 1:1, spreading lesion formation and progression were significantly (P < 0.001) decreased, suggesting that bacterial interaction (i.e., coaggregation) may have inhibited the spread of the P. gingivalis infection to a site distant from the initial injection. Infection with F. nucleatum and P. gingivalis simultaneously (at different sites) or F. nucleatum administered within 4 h prior to or 1 h following P. gingivalis infection significantly enhanced the ability of P. gingivalis to form large phlegmonous lesions. Chemical inhibition of the P. gingivalis trypsin-like protease activity or the use of a trypsin-negative P. gingivalis strain abrogated tissue destruction either alone or in combination with F. nucleatum. Therefore, it was possible to examine aspects of virulence of these pathogens in a murine lesion model by either altering bacterial ratios, manipulating the time of infection, or targeting vital bacterial virulence factors.

An experimental ovine foot abscess model using a Fusobacterium necrophorum biotype AB

An experimental procedure is described for the production of foot abscess in sheep that mimics the natural disease. Lesions were produced by the intradermal inoculation of suspensions of Fusobacterium necrophorum biotype AB containing from 5 x 10(2) to 5 x 10(8) bacteria, into interdigital skin devitalized by freezing with liquid nitrogen. A dose of 5 x 10(5) bacteria induced the development of foot abscess in 3 of 4 and 8 of 8 inoculated feet. It was found that to produce foot abscess in devitalized tissue required between 10(3) and 10(6) fewer bacteria than were necessary to produce similar lesions in healthy tissue.

Cytology of pulmonary Fusobacterium nucleatum infection. A case report

A patient with pulmonary Fusobacterium nucleatum infection presenting as a solitary nodule is reported. The infectious nature of the lung nodule was disclosed by ultrasound-guided percutaneous transthoracic fine needle aspiration cytology (FNAC) with Liu's stain. The cytologic characteristics of F nucleatum infection are described. The usefulness of real-time ultrasound in fine needle aspiration diagnosis of a peripheral lung lesion is demonstrated, and the role of Liu's stain in FNAC is emphasized.

Fusobacterium septic arthritis of the sternoclavicular joint

We describe a case of septic arthritis of the sternoclavicular joint caused by Fusobacterium in an otherwise healthy young man. The Fusobacterium had morphologic features most in keeping with Fusobacterium (F.) necrophorum, which was a common organism in sternoclavicular septic arthritis in the preantibiotic era. To our knowledge this is the first reported case of a fusobacterium sternoclavicular joint infection in the antibiotic era. This case should lead to heightened awareness of sternoclavicular joint infection and fusobacterium joint infection in the healthy host.

[Botryomycosis caused by fusobacteria]

In the Anglo-American literature botrymycosis is described as a chronic cutaneous granulomatous reaction to bacterial infection, containing granules resembling the sulphur granules seen in actinomycosis. The diagnostic and therapeutic aspects are discussed with reference to a recently observed patient. Fusobacterium nucleatum was isolated as the bacterial cause of the pathologic disorder.

Retroperitoneal necrotizing fasciitis

We present a case of retroperitoneal necrotizing fasciitis treated by urgent abdomino-perineal resection of the rectum with permanent colostomy. We can find no prior case in the English literature treated in this manner. Retroperitoneal occurrence of this disease is unusual. The process originated from perianal sepsis following chemotherapy for head and neck cancer.

Necrobacillosis--primary anaerobic septicaemia due to Fusobacterium necrophorum

Necrobacillosis is a severe septicaemic illness caused by an anaerobic Gram-negative bacillus, Fusobacterium necrophorum. It occurs predominantly in young people and is characterised by oropharyngeal infection and subsequent metastatic complications, frequently involving the lungs and/or large joints. We report four recent cases in previously healthy young men, describing the clinical features of the disease (including autopsy findings), and the problems associated with diagnosis and treatment.

Necrobacillosis

Necrobacillosis is a severe septicaemic illness caused by the gram negative anaerobe, Fusobacterium necrophorum, that typically occurs in previously healthy young adults following a mild sore throat. Radiological changes in the chest are prominent and include rapidly developing empyema, pneumonic consolidation, cavitation and pneumatocele formation. Metastatic abscesses in other sites are also seen. The clinical setting and time course are in marked contrast to the presentation of most anaerobic pleuro-pulmonary infections. Two cases are described, in one of which the outcome was fatal. Both displayed marked chest disease as an early manifestation of their illness. As the condition is relatively uncommon, radiological diagnosis demands a high index of suspicion in order to facilitate early treatment.