''Fusobacterium nucleatum'' is a
Gram
The gram (originally gramme; SI unit symbol g) is a unit of mass in the International System of Units (SI) equal to one one thousandth of a kilogram.
Originally defined as of 1795 as "the absolute weight of a volume of pure water equal to ...
negative, anaerobic oral
bacterium
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were a ...
, commensal to the human
oral cavity, that plays a role in
periodontal disease. This organism is commonly recovered from different monocultured microbial and mixed infections in humans and animals. In health and disease, it is a key component of periodontal
plaque due to its abundance and its ability to coaggregate with other bacteria species in the oral cavity.
Preterm births
Research implicates periodontal disease caused by ''F. nucleatum'' with
preterm births in humans. In many studies, ''F. nucleatum'' cells have been isolated from the
amniotic fluid,
placenta
The placenta is a temporary embryonic and later fetal organ (anatomy), organ that begins embryonic development, developing from the blastocyst shortly after implantation (embryology), implantation. It plays critical roles in facilitating nutrien ...
, and
chorioamnionic membranes of women
delivering prematurely. Moreover, laboratory mice inoculated (directly into the blood) with ''F. nucleatum'' have been found to deliver prematurely, and the pathology of the infection seems to mirror observations in humans. Together, this research provides evidence for a possible causal connection between ''F. nucleatum''-caused periodontal disease and at least some cases of preterm delivery. ''F. nucleatum'' can also be isolated from the vaginal microbiome, especially in women with a condition known as
bacterial vaginosis
Bacterial vaginosis (BV) is a disease of the vagina caused by excessive growth of bacteria. Common symptoms include increased vaginal discharge that often smells like fish. The discharge is usually white or gray in color. Burning with urinatio ...
. Both ''F. nucleatum'' vaginal colonization and bacterial vaginosis also have been linked with preterm birth and infections within the uterus. Thus, preterm birth arising by infections caused by ''F. nucleatum'' could also arise from invasive infection into the uterine tissue originating from the colonized vagina.
Colon cancer
''F. nucleatum'' has a demonstrated association with
colorectal cancer. ''Fusobacterium'' species have been found at higher quantities in certain types of colon tumors than in surrounding colon tissue or the colons of healthy individuals, but whether this is an indirect correlation or a causal link is unclear. A distinguishing mechanism has been described by which ''F. nucleatum'' creates a pro-inflammatory environment which is conducive to
tumor growth through the recruitment of tumor-infiltrating
immune cells, which, unlike other bacteria linked to colorectal carcinoma, does not exacerbate other pathological processes such as
colitis,
enteritis and inflammatory-associated intestinal carcinogenesis. This suggests direct and specific carcinogenesis. ''F. nucleatum'' can bind to host tissue
E-cadherins via a FadA, an outer membrane protein. Additionally, a surface expressed
lectin called Fap2 mediates ''F. nucleatum'' adherence to colorectal cancer cells that express
Gal/GalNAc moieties on their surface. Binding via Fap2 has also been shown to up-regulate production of
cytokines associated with higher rates of
metastasis.
See also
*
List of bacterial vaginosis microbiota
References
External links
Type strain of ''Fusobacterium nucleatum'' at Bac''Dive'' - the Bacterial Diversity Metadatabase
{{Taxonbar, from=Q5510311
Gram-negative bacteria
Bacterial vaginosis
Bacteria described in 1922
Fusobacteriota