Fusobacterium necrophorum

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]


Fusobacterium necrophorum is a species of bacteria responsible for Lemierre's syndrome and other medical problems. It is an obligate anaerobe and is a common inhabitant of the alimentary tract within humans and animals.


F. necrophorum is a rod-shaped species of Gram-negative bacteria. It is an obligate anaerobe and is a common inhabitant of the alimentary tract within humans and animals.[1]


F. necrophorum is responsible for 10% of acute sore throats,[2] 21% of recurrent sore throats[3][4] and 23% of peritonsillar abscesses[5] with the remainder being caused by Group A streptococci or viruses. Other complications from F. necrophorum include meningitis, complicated by thrombosis of the internal jugular vein, thrombosis of the cerebral veins,[6] and infection of the urogenital and the gastrointestinal tracts.[7]

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 should be excluded in cases of confirmed F. necrophorum occurring at sites caudal to the head.[8]


F. necrophorum infection (also called F-throat[9]) usually responds to treatment with penicillin or metronidazole, but penicillin treatment for persistent pharyngitis 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 horses. Thrush is a common fungal infection that occurs on the hoof of a horse, specifically in the region of the frog. F. necrophorum occurs naturally in the animal's environment, especially in wet, muddy, or unsanitary conditions, such as an unclean stall.[10] [11] 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. 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.[12]


Antimicrobial regimen

  • Fusobacterium necrophorum treatment[13]
  • 1. In adults
  • 2. In children
  • Preferred regimen: Combination therapy of Metronidazole 10–15 IV mg/kg q8h AND Ceftriaxone 80–100 mg/kg q12h
  • Alternative regimen (1): Imipenem
  • Alternative regimen (2): Ampicillin-Sulbactam
  • Alternative regimen (3): antipseudomonal penicillins
  • Alternative regimen (4): Clindamycin
  • Note: More frequent dosing of ceftriaxone is needed in cases of CNS infection.


  1. Tan, Z. L.; Nagaraja, T. G.; Chengappa, M. M. "Fusobacterium necrophorum infections: Virulence factors, pathogenic mechanism and control measures". Veterinary Research Communications. 20 (2): 113–140. doi:10.1007/BF00385634.
  2. Aliyu SH, Marriott RK, Curran MD; et al. (2004). "Real-time PCR investigation into the importance of Fusobacterium necrophorum as a cause of acute pharyngitis in general practice". J Med Microbiol. 53 (Pt 10): 1029&ndash, 35. doi:10.1099/jmm.0.45648-0. PMID 15358827.
  3. Batty A, Wren MW. (2005). "Prevalence of Fusobacterium necrophorum and other upper respiratory tract pathogens isolated from throat swabs". Br J Biomed Sci. 62 (2): 66&ndash, 70. PMID 15997879.
  4. Batty A, Wren MW, Gal M. (2004). "Fusobacterium necrophorum as the cause of recurrent sore throat: comparison of isolates from persistent sore throat syndrome and Lemierre's disease". J Infect. 51 (4): 299&ndash, 306. doi:10.1016/j.jinf.2004.09.013. PMID 16051369.
  5. Klug TE, Rusan M, Fuursted K, Ovesen T (2009). "Fusobacterium necrophorum: most prevalent pathogen in peritonsillar abscess in Denmark". Clin Infect Dis. 49 (10): 1467&ndash, 1472. doi:10.1086/644616. PMID 19842975. line feed character in |author= at position 18 (help)
  6. Larsen PD, Chartrand SA, Adickes M. (1997). "Fusobacterium necrophorum meningitis associated with cerebral vessel thrombosis". Pediatr Infect Dis J. 16 (3): 330&ndash, 331. doi:10.1097/00006454-199703000-00017. PMID 9076827.
  7. Hagelskjaer Kristensen L, Prag J. (200). "Human necrobacillosis, with emphasis on Lemierre's syndrome". Clin Infect Dis. 31 (2): 524&ndash, 532. doi:10.1086/313970. PMID 10987717.
  8. Redford ML, Ellis R, Rees CJ. (2005). "Fusobacterium necrophorum infection associated with portal vein thrombosis". J Med Microbiol. 54 (5): 993&ndash, 995. doi:10.1099/jmm.0.46080-0. PMID 16157556.
  9. "Sore Throat Misdiagnosis Could Kill Teenagers". The People's Pharmacy. February 19, 2015. Retrieved February 20, 2015.
  10. https://www.thehorse.com/articles/27319/the-lowdown-on-thrush
  11. Ensminger, M. E. (1990). Horses and Horsemanship: Animal Agriculture Series (Sixth ed.). Danville, IL: Interstate Publishers. p. 62. ISBN 0-8134-2883-1.
  12. http://www.defra.gov.uk/animalh/welfare/pdf/sheeplameness.pdf
  13. Kuppalli K, Livorsi D, Talati NJ, Osborn M (2012). "Lemierre's syndrome due to Fusobacterium necrophorum". Lancet Infect Dis. 12 (10): 808–15. doi:10.1016/S1473-3099(12)70089-0. PMID 22633566.

Further reading


  1. Machado, Vinícius Silva (March 17, 2014). "Subcutaneous Immunization with Inactivated Bacterial Components and Purified Protein of Escherichia coli, Fusobacterium necrophorum and Trueperella pyogenes Prevents Puerperal Metritis in Holstein Dairy Cows". PLoS ONE (2014). 9 (3): e91734. doi:10.1371/journal.pone.0091734.