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Fusobacterium nucleatum

Fusobacterium nucleatum is a microbe that lives in the mouth and is generally considered an oral bacteria. This bacteria can also be found in placenta. There are varying types of Fusobacterium, however, this specific nucleatum strain is one of the few of its kind to not use glucose for energy production. Its genus was first described in 1923 by Knorr, in Germany.

Etymology

The term Fusobacterium means that this microbe will not form spores, are gram negative, and are also anaerobic.  

Cell Composition

Fusobacterium nucleatum are often seen as spindles, but have also appeared in rod-shapes. These microbes, like many gram negative bacteria, have a pilus, an inner and outer membrane, and a cell wall. However, this microbe is not motile. This microbe is incredibly interesting because of the many things it's composition allows it to do.

Pathology

Fusobacterium nucleatum is often found in many other infections throughout the body. While not directly virulent themselves, they have the ability to adhere to other bacteria should they decide. This microbe makes a protein, RadD, which “ is responsible for arginine-inhibitable adherence of F. nucleatum” to other bacteria. RadD is one of the important proteins that allows for Fusobacterium Nucleatum to become pathogenic, in that it further aids in the proliferation of a biofilm in a host. Because of this protein, RadD, Fusobacterium Nucleatum is able to “act as a bridge between members of the oral biofilm that cannot directly bind to each other”. And, although it is not directly infecting a host, it’s bridge-like qualities allow for other pathogens to do so that may otherwise not be able to do so. Primarily acting as an oral bacterium, Fusobacterium nucleatum is one of the main contributers to plaque. Because of this microbe's ability to travel to the placenta as well as cause plaque, the plaque of a pregnant person has the potential to cause disease in newborns. Fusobacterium nucleatum also has the ability to make toxic metabolites that stop healthy cells from being able to repair themselves. Furthermore it can cause infections such as “tropical skin ulcers, peritonsillar abscesses, pyomyositis and septic arthritis, bacteremia and liver abscesses, intrauterine infections, bacterial vaginosis, urinary tract infections, pericarditis and endocarditis, and lung and pleuropulmonary infections”. Fusobacterium nucleatum secretes butyrate. This enzyme stops inflammation and, as a result, the host immune system from being alerted.

Genome

Fusobacterium Nucleatum's genome, according to MicrobeWiki, the Fusobacterium nucleatum “genome size is about 2.4x10^6 base pairs”. The genome of the specific nucleatum strain of Fusbacterium has a DNA coding sequence of 1,952,810. Some of this bacteria’s primary features are that it is gram-negative, it can adhere to other bacteria and surfaces. Each of these together allows this bacterium to be extremely pathogenic. Another feature of this bacteria is that each of its strains have the potential to vary greatly. Differences in the number of plasmids and chromosomes between Fusobacterium often occur. While generally, this bacteria has both small cryptic plasmids and average G/C content of 28%,  the nucleatum strain of Fusobacterium Nucleatum has a G/C content of 27%, no plasmids, and 1 chromosome.