Human infection with Fusobacterium necrophorum (Necrobacillosis), with a focus on Lemierre's syndrome

Abstract

Human infection with Fusobacterium necrophorum usually involves F. necrophorum subsp. funduliforme rather than F. necrophorum subsp. necrophorum, which is a common pathogen in animals. Lemierre's syndrome, or postanginal sepsis, is the most common life-threatening manifestation. Tonsillitis is followed by septic thrombophlebitis of the internal jugular vein and then a septicemia with septic emboli in lungs and other sites. Recent evidence suggests that F. necrophorum can be limited to the throat and cause persistent or recurrent tonsillitis. F. necrophorum is unique among non-spore-forming anaerobes, first for its virulence and association with Lemierre's syndrome as a monomicrobial infection and second because it seems probable that it is an exogenously acquired infection. The source of infection is unclear; suggestions include acquisition from animals or human-to-human transmission. Approximately 10% of published cases are associated with infectious mononucleosis, which may facilitate invasion. Recent work suggests that underlying thrombophilia may predispose to internal jugular vein thrombophlebitis. Lemierre's syndrome was relatively common in the preantibiotic era but seemed to virtually disappear with widespread use of antibiotics for upper respiratory tract infection. In the last 15 years there has been a rise in incidence, possibly related to restriction in antibiotic use for sore throat.

FIG. 1.

Line drawings of Bacillus funduliformis from a thesis by Jean Hallé (182). Top left, common short, slightly curved rods seen in pus and tissues; top right, rare giant forms; bottom left, poorly staining vesicular forms sometimes seen in culture; bottom right, bizarre pleomorphic forms commonly seen in culture. Drawings are not on the same scale.

FIG. 2.

André Lemierre. (Courtesy of the U.S. National Library of Medicine.)

FIG. 3.

Summary of cases identified from the literature after 1970 and contained in the database.

FIG. 4.

Patient groups: necrobacillosis and Lemierre's syndrome. Circle A, postanginal sepsis with internal jugular vein thrombosis and metastatic manifestations; circle B, necrobacillosis; 1, classical Lemierre's postanginal sepsis; 2, clinical Lemierre's syndrome but F. necrophorum not detected; 3, necrobacillosis with other source.

FIG. 5.

Distribution of extrapulmonary metastatic lesions in 59/222 cases fitting the current case definition of Lemierre's syndrome cases.

FIG. 6.

Referrals of Fusobacterium necrophorum to the United Kingdom Anaerobe Reference Laboratory in 1992 to 2004. (Reprinted from reference with permission from Elsevier.)

FIG. 7.

Putative sequence of events after throat infection with Fusobacterium necrophorum.