Bacterial challenge model in cattle using a trans- and intra-dermal route to infect peripheral lymph nodes
Inventors
Loneragan, Guy • Edrington, Thomas
Assignees
Firmenich Inc • Texas Tech University TTU • US Department of Agriculture USDA
Publication Number
US-10114019-B2
Publication Date
2018-10-30
Expiration Date
2034-03-04
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Abstract
The present invention includes a method of observing and evaluating bacterial infections within the lymph nodes of animals presented for harvest comprising: inoculating at one or more sites of an animal a known amount of a pathogen, wherein the one or more inoculation sites comprise lymph node drainage areas, and at one or more time points obtaining one or more lymph node biopsies to determine the extent of the pathogen in the lymph nodes.
Core Innovation
The present invention provides a method of observing and evaluating bacterial infections within the lymph nodes of animals presented for harvest by inoculating one or more sites of an animal with a known amount of a pathogen. These inoculation sites are selected from lymph node drainage areas, and at one or more time points, lymph node biopsies are obtained to determine the extent of the pathogen within the lymph nodes. The inoculation can be performed subdermally or transdermally, and the method applies to a variety of pathogens including Salmonella, Listeria, Shigella, Fransicella, Clostridum, Staphylococcus, Streptococcus, Bacillus, as well as viral, fungal, protozoan, and helminthic pathogens. Animals of various species such as bovine, equine, ovine, porcine, and caprine are suitable for this method.
The invention addresses the problem of inconsistent and unpredictable infection of peripheral lymph nodes (PLNs) in cattle using traditional oral challenge models. It recognizes that non-mesenteric lymph nodes may be significant sources of pathogens such as Salmonella contaminating ground beef and that current approaches, including oral inoculation, fail to consistently establish infection in these nodes. The inventors developed a trans- and intra-dermal route using a multi-inoculator (e.g., lancet) allergy skin-testing device to deliver bacterial pathogens to specific skin regions drained by targeted lymph nodes, providing a more reliable and region-specific infection model.
This model offers a novel and applicable approach to predictably infect PLNs with pathogens like Salmonella, enabling studies on the duration of infection and the efficacy of interventions such as vaccines or treatments. The method improves upon prior art by allowing concurrent multi-site inoculations intradermally or subdermally, resulting in predictable recovery of targeted bacterial strains from corresponding draining lymph nodes. It also allows evaluation of therapies or compounds by assessing their effect on pathogen elimination or reduction within lymph nodes.
Claims Coverage
The patent includes three independent claims that cover methods of observing bacterial infections, observing and evaluating treatment efficacy, and testing compounds for elimination of bacterial pathogens in animal lymph nodes using intradermal or subdermal inoculation at lymph node drainage areas.
Method of observing bacterial infections using intradermal multi-site inoculation
The method involves inoculating intradermally with a device capable of concurrently inoculating multiple sites of an animal with a known amount of a live bacterial pathogen selected from Salmonella, Listeria, Shigella, Fransicella, Clostridum, Staphylococcus, Streptococcus, or Bacillus. The inoculation sites comprise lymph node drainage areas. At one or more time points, lymph node biopsies are aseptically harvested to determine the extent of bacterial pathogen presence.
Method of evaluating therapies or treatments on bacterial infections in lymph nodes
This method includes intradermal inoculation using a multi inoculator at one or more sites comprising lymph node drainage areas with a live bacterial pathogen from specified genera. Following inoculation, animals are treated with one or more therapies, treatments, or exposures. Lymph node biopsies are obtained at one or more time points to determine pathogen extent, enabling determination of the effectiveness of the therapies or treatments in eliminating or reducing the bacterial pathogen.
Method of testing compounds for eliminating bacterial infections within lymph nodes
This method encompasses intradermal inoculation using a multi inoculator at lymph node drainage sites with a known amount of live bacterial pathogen. The animal is treated with one or more compounds, followed by lymph node biopsies at defined time points to assess the extent of pathogen presence, thereby determining if the compound effectively eliminates or reduces the bacterial pathogen.
The claims cover novel methods of administering live bacterial pathogens intradermally or subdermally to lymph node drainage areas in animals, combined with subsequent biopsy and pathogen quantification to observe infection, evaluate treatments, or test compounds. These inventive features establish a reliable challenge model using multi-site inoculation targeting lymph nodes and facilitate assessment of intervention effectiveness.
Stated Advantages
The trans- and intra-dermal inoculation route predictably results in Salmonella-positive peripheral lymph nodes, providing a consistent infection model.
The model allows estimation of the duration of infection and evaluation of candidate interventions, such as vaccines, to reduce or eliminate bacterial carriage in lymph nodes.
The method enables examination of multiple pathogen serotypes within the same animal via region-specific inoculation, allowing the animal to serve as its own control and reducing the number of animals needed for studies.
Use of a multi-inoculator device, such as a 10-microlancet allergy skin-testing instrument, requires minimal restraint, is well tolerated by animals, and avoids adverse effects such as lameness or swelling seen with syringe inoculations.
Documented Applications
Development of bacterial challenge models in cattle to predictably infect peripheral lymph nodes with Salmonella and other bacterial pathogens.
Evaluation of vaccines and other therapeutic interventions to reduce bacterial carriage and infection in lymph nodes of animals presented for harvest.
Testing compounds for efficacy in eliminating or reducing bacterial infections within animal lymph nodes.
Studying infection dynamics, including duration and regional specificity, of bacterial pathogens within lymph nodes following transdermal or intradermal inoculation.
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