Leukotoxin production by Fusobacterium necrophorum strains in relation to severity of liver abscesses in cattle

Pillai, Deepti; Amachawadi, Raghavendra G.; Baca, Giovanna; Narayanan, Sanjeev; Nagaraja, T. G.

doi:10.1016/j.anaerobe.2021.102344

Cited by 13 publications

(7 citation statements)

References 32 publications

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“…Among them, leukotoxin is an extracellular secretory protein, F. necrophorum's most important virulence factor, which can inhibit the phagocytosis of neutrophils and Kupffer cells (13)(14)(15). Studies have shown that the amount of leukotoxin secreted by F. necrophorum correlates positively with the severity of liver abscess in cattle (16).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Immunoprotective Effects of Fusobacterium necrophorum Outer Membrane Proteins 43K OMP, Leukotoxin and Hemolysin Multi-Component Recombinant Subunit Vaccine in Mice

Xiao

Jiang

et al. 2021

Front. Vet. Sci.

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We evaluated the efficacy of three vaccine formulations containing different combinations of proteins (43K OMP, leukotoxin recombinant protein PL4 and hemolysin recombinant protein H2) and killed whole cell Fusobacterium necrophorum in preventing liver abscess. Four subcutaneous vaccines were formulated: vaccine 1 (43K OMP), vaccine 2 (PL4 and H2), vaccine 3 (43K OMP, PL4 and H2), and vaccine 4 (killed whole bacterial cell). 43K OMP, PL4, and H2 proteins were produced by using recombinant protein expression. To evaluate vaccine efficacy, we randomly allocated 50 BALB/c female mice to one of five different treatment groups: PBS control group, vaccine 1, vaccine 2, vaccine 3, and vaccine 4. Mice were vaccinated three times, with 14 days between each immunization. After immunization, the mice were challenged with F. necrophorum. The three key findings of this study are as follows: (1) Vaccine 3 has enabled mice to produce higher antibody titer following bacterial challenge, (2) in the liver pathology of mice, the vaccine 3 liver showed the least pathology, and (3) all four vaccines produced high levels of antibodies and cytokines in mice, but the level of vaccine 3 was the highest. Based on our results, it has been demonstrated that a mixture of F. necrophorum 43K OMP, PL4, and H2 proteins inoculated with mice can achieve protection against liver abscess in mice. Our research may therefore provide the basis for the development of a vaccine against F. necrophorum bovine infections.

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Section: Introductionmentioning

confidence: 99%

Evaluation of Immunoprotective Effects of Fusobacterium necrophorum Outer Membrane Proteins 43K OMP, Leukotoxin and Hemolysin Multi-Component Recombinant Subunit Vaccine in Mice

Xiao

Jiang

et al. 2021

Front. Vet. Sci.

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“…However, many of the Type II DMTases do not have a paired REases as shown in Figure 1C , therefore it is difficult to understand what could be cleaving the unmethylated DNA sequences that corresponds to specific enzymes. In addition, expanding beyond the realm of only studying F. nucleatum to other species including F. necrophorum could be key to understanding the pathogenicity of this species in Lemierre’s syndrome in humans 75 , as well as serious organ infections in livestock 76 .…”

Section: Discussionmentioning

confidence: 99%

DNA methyltransferase enhanced Fusobacterium nucleatum genetics

Umaña

Nguyen

Sanders

et al. 2022

Preprint

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Bacterial restriction-modification (R-M) systems are a first line immune defense against foreign DNA from viruses and other bacteria. While R-M systems are critical in maintaining genome integrity, R-M nucleases unfortunately present significant barriers to targeted genetic modification. Bacteria of the genus Fusobacterium are oral, Gram-negative, anaerobic, opportunistic pathogens that are implicated in the progression and severity of multiple cancers and tissue infections, yet our understanding of their direct roles in disease have been severely hindered by their genetic recalcitrance. Here, we demonstrate a path to overcome these barriers in Fusobacterium by using native DNA methylation as a host mimicry strategy to bypass R-M system cleavage of user introduced plasmid DNA. We report the identification, characterization, and successful use of Fusobacterium nucleatum (Fn) Type II and III DNA methyltransferase (DMTase) enzymes to produce a multi-fold increase in gene knockout efficiency in the strain Fusobacterium nucleatum subsp. nucleatum 23726 (Fnn 23726), as well as the first efficient gene knockouts and complementations in Fnn 25586. We show plasmid protection can be accomplished in vitro with purified enzymes, as well as in vivo in an E. coli host that constitutively expresses Fnn DMTase enzymes. By characterizing specific DMTases that are critical for bypassing R-M systems, we have enhanced our understanding of potential enzyme combinations, with the goal of expanding these studies to genetically modify clinical isolates of Fusobacterium that have thus far been inaccessible to molecular characterization. This proof-of-concept study provides a roadmap to guide molecular microbiology efforts of the scientific community to facilitate the discovery of new Fusobacterium virulence genes, thereby leading to a new era of characterizing how an oral opportunistic pathogen contributes to an array of human infections and diseases.IMPORTANCEFusobacterium nucleatum is an oral opportunistic pathogen associated with diseases including cancer and preterm birth. Our understanding of how this bacterium modulates human disease has been hindered by a lack of genetic systems. Here we show that F. nucleatum DNA methyltransferase modified plasmid DNA overcomes the transformation barrier and allows the development of genetic systems in previously inaccessible strains. We present a strategy that can be expanded to enable the genetic modification of clinical isolates, thereby fostering investigational studies to uncover novel host-pathogen interactions in Fusobacterium.

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“…The bacterium, a member of the microbial community of the rumen, travels to the liver via portal circulation to cause abscesses. The severity of liver abscesses varies from mild with one or two small abscesses to severe with medium to large multiple abscesses (Pillai et al, 2021). Abscesses on the hepatic surface may extend causing phlebitis in the caudal vena cava, whose inflammation leads to bacterial thrombi and emboli formation and, depending on the number of thrombi and microorganisms involved, a series of changes might occur that collectively form the so-called caudal vena cava syndrome.…”

Section: Discussionmentioning

confidence: 99%

“…Metabolic acidosis causes alterations in the ruminal mucosa, characterized by hyperkeratosis and inflammation due to local lactic acid accumulation, allowing bacteria translocation from the gastrointestinal tract into the bloodstream, and the formation of hepatic abscesses (Pillai et al, 2021;Quevedo et al, 2015). For Constable et al (2016) and Smith (2006), the bacteria involved in ruminitis are Fusobacterium necrophorum, Arcanobacterium pyogenes, Staphylococci, Streptococcus, Escherichia coli, which reach the liver forming abscesses that rupture, causing secondary pneumonia (Motta et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Cardiocongestive insufficiency due to vena cava thrombosis with secondary necro-exudative bronchopneumonia

Strapasson¹,

Rossi²,

Moura³

et al. 2021

Pubvet

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O objetivo deste estudo foi relatar um caso de trombose da veia cava com broncopneumonia secundária em uma vaca holandesa de dois anos de idade oriunda do município de Jacutinga, Rio Grande do Sul. A trombose da veia cava é uma enfermidade que acomete bovinos adultos que são alimentados com dietas a base de concentrados, caracteriza-se pela presença de êmbolos sépticos na corrente sanguínea, os quais são formados a partir de trombos da veia cava caudal que obliteram o lúmen vascular, causando hipóxia tecidual. A etiologia mais comum de trombose da veia cava é a acidose ruminal, gerando ruminite e subsequente abscedação do fígado e tromboembolismo da artéria pulmonar, úlceras de abomaso e polioencefalomalácia. O animal estava no terço final da gestação quando apresentou mastite, dor ao caminhar e tosse, recebia alimentação a base de silagem de milho e ração balanceada com 20 % de proteína. Foi realizado o tratamento para mastite e após 15 dias ao primeiro tratamento foi realizada antibioticoterapia a base de enrofloxacina, intramuscular. O animal veio ao óbito e dados de necropsia e histopatológicos indicaram ser compatíveis com insuficiência cardiocongestiva possivelmente por trombose na veia cava com broncopneumonia necroexudativa secundária.

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Leukotoxin production by Fusobacterium necrophorum strains in relation to severity of liver abscesses in cattle

Cited by 13 publications

References 32 publications

Evaluation of Immunoprotective Effects of Fusobacterium necrophorum Outer Membrane Proteins 43K OMP, Leukotoxin and Hemolysin Multi-Component Recombinant Subunit Vaccine in Mice

Evaluation of Immunoprotective Effects of Fusobacterium necrophorum Outer Membrane Proteins 43K OMP, Leukotoxin and Hemolysin Multi-Component Recombinant Subunit Vaccine in Mice

DNA methyltransferase enhanced Fusobacterium nucleatum genetics

Cardiocongestive insufficiency due to vena cava thrombosis with secondary necro-exudative bronchopneumonia

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