Pathogenicity of Fusobacterium necrophorum strains from man and animals

Abstract

SUMMARYNecrobacillosis occurs in man and animals. The typical forms of the disease in animals are caused by Fusobacterium necrophorum biovar A; biovar B strains are much less pathogenic. In this study the pathogenicity for mice of eight human isolates of F. necrophorum was compared with that of animal biovar A and B strains.By subcutaneous inoculation seven of the human strains differed from biovar A but resembled biovar B in (1) producing, at the most, mild local lesions that rapidly healed, and (2) Nonetheless, strain A2433 differed from biovar A, both in the nature of the lesions produced and in its failure to cause severe general signs of illness and rapidly fatal infection.By intravenous inoculation one of two biovar B strains and all except one of the eight human strains produced purulent lesions, often severe, in the liver and elsewhere, but infection was not usually associated with general signs of illness. In contrast, intravenous injection of a biovar A strain gave rise to a rapidly fatal infection, with severe lesions in the liver or elsewhere.The results suggest that the term 'necrobacillosis' as used in human and veterinary medicine refers to diseases that differ in important respects.

Pathogenesis of cancrum oris (noma): confounding interactions of malnutrition with infection.

“…Fusobacterium necrophorum has little ability to invade intact epithelium, and infection usually arises from contamination of damaged mucosa following ulceration/abrasions, trauma, or a debilitating condition. 25,80 Based on our previously published microbiologic data, 22,28 and the present biochemical findings, we have proposed a tentative scheme to explain the pathogenesis of noma in deprived Nigerian children ( Figure 3). As indicated in the scheme and extensively reported in the literature, 56,74,81 a complex three-way relationship exists between malnutrition, immune dysfunctions in the host, and increased susceptibility to infections.…”

“…1,10,28,77 The main pathogen involved in animal necrobacillosis is F. necrophorum (biovar A strains), and its infective dose is drastically reduced by the concurrent presence of other bacterial species particularly Escherichia coli, Staphylococcus aureus, Bacteroides species, peptostreptococci, and various aerobes and facultative anaerobes. 78 The periodontal tissues and face are the sites most commonly affected by necrobacillosis in wallabies, 25,79 and studies show that F. necrophorum is the predominant microorganism occurring in 69% of the lesions. 26 At this stage, we have not confirmed whether the strains of F. necrophorum isolated from human noma are similar to the animal biovars.…”

“…3,4 The latter suspicion derives from the observation of very close residential proximity of vulnerable Nigerian children to livestock, 3 as well as published reports that gangrenous processes similar to noma in the human, occur in the latter, and attributed to infection by Fusobacterium necrophorum. [24][25][26] Significantly more anaerobes, particularly Prevotella intermedia, are present in the mouths of malnourished Nigerian children compared with their well nourished counterparts, regardless of the presence or absence of any overt oral pathology. 27 Ongoing studies in Nigerian children indicate recovery of F. necrophorum from 88% of the noma lesions.…”

Isolation of Fusobacterium necrophorum from cancrum oris (noma).

“…36 Initial work trying to determine if human strains will fit into current animal biovar designations suggests that strains isolated from humans may not follow the animal biovar designation. 37 Although not frequently isolated, infections in humans involving F. necrophorum include necrotic tonsillitis with post-anginal septicemia (Lemierre's syndrome), [38][39][40][41] oral and dental infections, brain abscesses, empyema, hepatic and intra-abdominal abscesses, and endocarditis, [42][43][44] and mastoiditis, meningitis, and venous sinus thrombosis. 45 Whether P. intermedia was the black-pigmented member of the organisms considered as Bacteroides melaninogenicus in earlier work associated with noma lesions is not clear.…”

Phenotypic characteristics and lipopolysaccharides of human and animal isolates of Fusobacterium necrophorum

“…It has been shown, with the exception of one aberrant strain (not included in this study), that human isolates resemble those of biotype B in being of low pathogenicity in mice [22]. In this study, the type strain (JCM 3724), all four putative biotype B and all 21 human isolates had a rough type LPS.…”