Conversion of Immunodeficient Rodent Models to the Excluded Flora Health Standard

Taconic is converting production of many immunodeficient models from the Restricted Flora™ (RF™) health standard to the Excluded Flora (EF) health standard as part of continuous quality improvements. The next model identified for conversion to Excluded Flora production in the U.S. is the NIH nude rat, with a target date for conversion by July 27, 2018.

FAQs on the Excluded Flora (EF) Health Standard

What are the differences between the Excluded Flora and Restricted Flora™ health standards?
  • The RF™ standard excludes several opportunistic pathogens: Beta hemolytic Streptococcus (non-Group D), Klebsiella pneumoniae, Klebsiella oxytoca, Pseudomonas aeruginosa, Staphylococcus aureus and Pasteurella multocida.
  • The EF standard excludes Proteus spp. and Segmented Filamentous Bacteria (SFB) in addition to organisms excluded in the RF™ health standard.
  • The Excluded Flora health standard, unique to Taconic, enables investigators to obtain selected Taconic mouse and rat lines that are free of eight well-documented confounding commensal organisms.

Opportunistic pathogen or commensal organismRF™ Accepted?OF™ Accepted?EF Accepted?
Beta hemolytic Streptococcus (non Group D) NoNoNo
Klebsiella oxytocaNoNoNo
Klebsiella pneumoniaeNoNoNo
Pseudomonas aeruginosaNoNoNo
Staphylococcus aureusNoNoNo
Pasteurella multocidaNoNoNo
Proteus spp.YesNoNo
Segmented Filamentous Bacteria (SFB, a normal rodent commensal)YesYesNo

Why is Taconic converting some immunodeficient rodent lines from the RF™ to the EF standard?
  • Taconic has experienced increased customer demand for immunodeficient animals free of Proteus mirabilis.
  • Proteus mirabilis is a gram negative, anaerobic, rod-shaped bacterium that has become a concern for researchers working with immunodeficient rodent models.
  • In mice with immune dysfunction, Proteus mirabilis has been described as causing sepsis and may be associated with urinary tract infections.
  • Literature reports have described infections in the kidney, enlarged spleens and hepatic lesions from Proteus.
  • Segmented Filamentous Bacteria is of particular interest for many immunology and oncology studies. SFB is not a pathogen and has not been directly associated with disease causation, however it has been shown to impact immune response.

What is the difference in price for Excluded Flora models in relation to Restricted Flora™?
  • For immunodeficient rodent models such as NIH nude rat, EF and RF™ animals are priced the same.
  • For immunocompetent models, the EF price is somewhat higher than the Murine Pathogen Free™ model price due to husbandry differences.

Read more about Taconic health standards and choosing a health standard.

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