Animals that have a normal intestinal flora but are free of particular disease-causing organisms are called what?

Animals that have a normal intestinal flora but are free of particular disease-causing organisms are called what?

• A. Axenic
• B. Specific Pathogen Free
• C. Defined Flora
• D. Normal

Answer: (B)

The concept tested is how lab animals are categorized by pathogen status. Specific Pathogen Free describes animals that have a normal, healthy gut microbiota (the usual commensal flora) but have been screened and maintained to be free from a defined list of disease-causing organisms. This means they are not germ-free, but they do not carry those targeted pathogens, which is essential for many experiments where certain infections could confound results. Axenic would mean completely germ-free, with no microorganisms at all, which is not the case here. Defined Flora refers to animals whose gut microbiota is deliberately limited to a known, specified set of microorganisms, not specifically about excluding pathogens. Normal is not a formal health-status designation and lacks the specificity of excluding particular pathogens. So, animals with a normal intestinal flora but free of certain disease-causing organisms are described as Specific Pathogen Free.

The concept tested is how lab animals are categorized by pathogen status. Specific Pathogen Free describes animals that have a normal, healthy gut microbiota (the usual commensal flora) but have been screened and maintained to be free from a defined list of disease-causing organisms. This means they are not germ-free, but they do not carry those targeted pathogens, which is essential for many experiments where certain infections could confound results.

Axenic would mean completely germ-free, with no microorganisms at all, which is not the case here. Defined Flora refers to animals whose gut microbiota is deliberately limited to a known, specified set of microorganisms, not specifically about excluding pathogens. Normal is not a formal health-status designation and lacks the specificity of excluding particular pathogens.

So, animals with a normal intestinal flora but free of certain disease-causing organisms are described as Specific Pathogen Free.