''Fusobacterium necrophorum'' is a species of

bacteria Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...

responsible for Lemierre's syndrome. It has also been known to cause

sinusitis Sinusitis, also known as rhinosinusitis, is an inflammation of the mucous membranes that line the sinuses resulting in symptoms that may include production of thick nasal mucus, nasal congestion, facial congestion, facial pain, facial pressure ...

, mastoiditis, and odontogenic infections.

Biology

''F. necrophorum'' is a rod-shaped species of

Gram-negative bacteria Gram-negative bacteria are bacteria that, unlike gram-positive bacteria, do not retain the Crystal violet, crystal violet stain used in the Gram staining method of bacterial differentiation. Their defining characteristic is that their cell envelo ...

. It is an

obligate anaerobe Obligate anaerobes are microorganisms killed by normal Atmosphere of Earth, atmospheric concentrations of oxygen (20.95% O2). Oxygen tolerance varies between species, with some species capable of surviving in up to 8% oxygen, while others lose vi ...

and is a common inhabitant of the

alimentary tract The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The tract is the largest of the body's systems, after the cardiovascular system. T ...

within humans and animals.

Pathogenicity

''F. necrophorum'' is responsible for 10% of acute

sore throat Sore throat, also known as throat pain, is pain or irritation of the throat. The majority of sore throats are caused by a virus, for which antibiotics are not helpful. For sore throat caused by bacteria (GAS), treatment with antibiotics may hel ...

s, 21% of recurrent sore throats and 23% of peritonsillar abscesses with the remainder being caused by

Group A streptococci Group A streptococcal infections are a number of infections with ''Streptococcus pyogenes'', a group A streptococcus (GAS). ''S. pyogenes'' is a species of beta-hemolytic Gram-positive bacteria that is responsible for a wide range of infect ...

virus A virus is a submicroscopic infectious agent that replicates only inside the living Cell (biology), cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Viruses are ...

es. Other complications from ''F. necrophorum'' include

meningitis Meningitis is acute or chronic inflammation of the protective membranes covering the brain and spinal cord, collectively called the meninges. The most common symptoms are fever, intense headache, vomiting and neck stiffness and occasion ...

, complicated by

thrombosis Thrombosis () is the formation of a Thrombus, blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel (a vein or an artery) is injured, the body uses platelets (thrombocytes) and fib ...

of the

internal jugular vein The internal jugular vein is a paired jugular vein that collects blood from the brain and the superficial parts of the face and neck. This vein runs in the carotid sheath with the common carotid artery and vagus nerve. It begins in the posteri ...

of the cerebral veins, and infection of the

urogenital The genitourinary system, or urogenital system, are the sex organs of the reproductive system and the organ (biology), organs of the urinary system. These are grouped together because of their proximity to each other, Development of the urinary a ...

and the

gastrointestinal The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The tract is the largest of the body's systems, after the cardiovascular system. ...

tracts. Although this infection is rare, researchers agree that this diagnosis should be considered in a septicaemic patient with thrombosis in an unusual site, and underlying

malignancy Malignancy () is the tendency of a medical condition to become progressively worse; the term is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous ''benign'' tumor in that a malignancy is not ...

should be excluded in cases of confirmed ''F. necrophorum'' occurring at sites caudal to the head. The above statistical analysis is dated, necessarily. A 2015 study of young adult students presenting to a single clinic in Alabama had ''F. necrophorum'' as the predominant causative organism for pharyngitis 21% of the time (and found in 9% of asymptomatic students). In the same study, Group A Streptococcus was found in 10% of pharyngitis patients (1% of asymptomatic students).

Treatment

''F. necrophorum'' infection (also called F-throat) usually responds to treatment with augmentin or

metronidazole Metronidazole, sold under the brand name Flagyl and Metrogyl among others, is an antibiotic and antiprotozoal medication. It is used either alone or with other antibiotics to treat pelvic inflammatory disease, endocarditis, and bacterial vagino ...

, but penicillin treatment for persistent

pharyngitis Pharyngitis is inflammation of the back of the throat, known as the pharynx. It typically results in a sore throat and fever. Other symptoms may include a runny nose, cough, headache, difficulty swallowing, swollen lymph nodes, and a hoarse vo ...

appears anecdotally to have a higher relapse rate, although the reasons are unclear.

Infection in animals

This bacterium has been found to be associated with the foot disease thrush in

horse The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 mi ...

s. Thrush is a common infection that occurs on the

hoof The hoof (: hooves) is the tip of a toe of an ungulate mammal, which is covered and strengthened with a thick and horny keratin covering. Artiodactyls are even-toed ungulates, species whose feet have an even number of digits; the ruminants with ...

of a horse, specifically in the region of the

frog A frog is any member of a diverse and largely semiaquatic group of short-bodied, tailless amphibian vertebrates composing the order (biology), order Anura (coming from the Ancient Greek , literally 'without tail'). Frog species with rough ski ...

. ''F. necrophorum'' occurs naturally in the animal's environment, especially in wet, muddy, or unsanitary conditions, such as an unclean stall. Horses with deep clefts, or narrow or contracted heels are more at-risk to develop thrush. ''F. necrophorum'' is also a cause for lameness in sheep. Its infection is commonly called scald or foot rot. It can last for several years on land used by either sheep or cattle, and is found on most land of this type throughout the world. Due to its survival length in these areas, it is unrealistic to try to remove it. Sheep most often get scald due to breakage or weakness of the skin surrounding the hoof. This can occur due to strong footbaths, sandy soils, mild frostbite, or prolongened waterlogging of a field, and results in denaturing of the skin between the cleats. ''F. necrophorum'' is the cause of necrotic laryngitis ("calf diphtheria") and liver abscesses in cattle. :''See also Blain, an archaic disease of uncertain etiology.''

References

External links