FUSOBACTERIUM NUCLEATUM

[Drsumitra]

Some bacteria may make people susceptible to many others.

Fusobacterium nucleatum enables other bacteria, such as Eserichia coli to enter a person’s body through the bloodstream, resulting in illness, according to a research team at Case Western University. Yiping Ham, professor of periodontics at Case Western Reserve School of Dental Medicine, made the finding after analyzing Fusobacterium nucleatum, which is some of the most common bacteria present in the mouth.

This bacteria has a type of bonding agent that breaks the junctures of the interlocking sheath of endothelial cells, which is the way the bacteria enables a path for other bacteria to enter the blood.

It’s been determined that there’s a correlation between this oral bacteria and preterm death and fetal death. This bacteria has also been associated with other infections and abscesses in the lungs, liver, brain, spleen and joints.

After pinpointing and genetically matching the bacteria in the case of fetal death, Han began to realize how an oral bacterium can be located throughout the body and manages to get through placental barriers. After entering the body due to an injury or periodontal disease, F. nucleatum is unique because it produces signals that allow it spread throughout the body.

To confirm the abilities of F. nucleatum, researchers introduced E. coli into a bond. Before F. nucleatum was present, the bond did not break simply from E. coli. After F. nucleatum was present, however, the bond broke because of E. coli.

After ending its ride through the bloodstream, F. nucleatum starts to colonize. That’s when the major illnesses and possible death result.

        

[Drsumitra]

        

[drsushant]

 Fusobacterium nucleatum is a gram-negative anaerobe, which belongs to theBacteroidaceae family and is found naturally in the microflora of the mouth in healthy or diseased humans. F. nucleatum is a very long rod with tapering ends and is one of the dominant species of the 500 or more organisms that coexist in the oral cavity (21). Many of the oral flora are commensals but a few are opportunistic pathogens. F. nucleatum can be isolated not only from the mouth but also from infections such as skin ulcers, peritonsillar abscesses, septic arthritis, and endocarditis (5). Several species of Fusobacterium have been isolated and studied, including F. necrophorum(the causative agent of Lemierre’s syndrome), F. ulcercans (skin ulcers), F. russi(animal bite infections), and F. varium (eye infections), with F. nucleatum and F. necrophorum considered to be the most pathogenic.

In the initial stages of the periodontal disease process, saccharolytic, aerobicStreptococcus spp. and other bacteria adhere to and colonize the tooth enamel and root surface. This sets the stage for F. nucleatum to coaggregate with these early colonizers and to permit late colonizers, including dental pathogens, to eventually form a biofilm. These complex interactions result in the release of factors that lead to tooth decay. Physical interaction is very specific among various genera in this complex microbial community. Due to the unusual length, adhesive nature, and other cell surface properties of F. nucleatum, periodontal disease-causing bacteria such as Porphyromonas gingivalis, Bacteroides forsythus, Actinobacillus actinomycetemcomitans, Treponema denticola, and Streptococcus spp. aggregate and thrive; hence, F. nucleatum is referred to as a “bridge bacterium” (5). The interaction between F. nucleatum and P. gingivalis has been reported to be very specific (19), mediated by a lactose-binding adhesin (20). The same adhesin protein mediates the binding of F. nucleatum to a variety of eukaryotic cell types including HeLa cells, buccal epithelial cells, macrophages, polymorphonuclear leukocytes, and gingival and periodontal ligaments (46). Helicobacter pylori was also shown to adhere selectively to F. nucleatum (1).

Research on Fusobacterium spp. has focused primarily on species identification, oral ecology, cell-cell communication, extracellular surfaces, amino acid degradation, carbohydrate metabolism, organic acid fermentation, and antibiotic resistance (5,21). However, many metabolic pathways and their roles in survival in such specialized niches are not known. Genetic experiments have been hampered by the lack of molecular tools, although recently three plasmids, pFN1, pFN2, and pFN3, have been isolated and sequenced from the strain ATCC 10953. A transformation system has been developed for gene manipulation using the pFN1 ori sequence (14).

Although many potential virulence candidates have been described, very few of them have been studied experimentally. In an effort to understand globally its genetic, metabolic, and pathogenic features, we analyzed the genome sequence of F. nucleatum strain ATCC 25586 and present here the results of this analysis. This is the first determination of a Fusobacterium spp. genome sequel

        

[Anonymous]

Fusobacterium nucleatum is an anaerobic Gram-negative non-sporeforming bacterium, and the type species for the genus Fuosbacterium. The species has a low G+C content (27 to 28%), and phylogenetic studies group the fusobacteria as a branch among the high and low G+C Gram-positive bacteria.

The cells of F. nucleatum are spindle-shaped or fusiform rods of variable length. All strains obtain energy from the fermentation of sugars or amino acids, and produce butyric acid as a major metabolic by-product. F. nucleatum is found in the dental plaque of primates, including man. This microorganism has been postulated to play a central role in dental plaque formation, based on its ability to adhere to a wide range of both Gram-positive and Gram-negative plaque microorganisms. F. nucleatum is frequently associated with periodontitis, as well as invasive human infections of the head and neck, chest, lung, liver and abdomen. Properties of F. nucleatum that may be related to virulence include it’s adherence to and invasion of host tissue cells, and modulation of the host immune response. Native plasmids have been identified in strains of F. nucleatum, and an F. nucleatum – E. coli shuttle vector has been developed using the native plasmid pFN1.

        

[Anonymous]

FUSOBACTERIUM  NUCLEATUM

        

[Author]

Posts