The National Gnotobiotic Rodent Resource Center funded by NCRR's Comparative Medicine section since 2004 provides germ-free and selectively colonized rodents to requesting investigators. Germ-free rodents are axenic, with no detectible bacteria, yeast, molds, parasites or viruses (except retroviruses). Germ-free rodent strains are surgically derived by sterile embryo transfer to gnotobiotic recipients performed within a custom designed surgical isolator chamber. Strains are then maintained in sterile flexible film Trexler isolators. These animals can be selectively innoculated with various bacterial species, either singly (monoassociation) or in combination, to study their effects on the host. Once colonized, these rodents are maintained as gnotobiotics by housing them in barrier intact isolators to avoid cross contamination with other bacteria. Investigators can precisely manipulate the microbiota by selectively colonizing germ-free rodents with single or multiple commensal, pathogenic, bacterial or fungal species using isogenic wild type or genetically engineered bacterial srains.
Services of NGRRC include: shipment of colonized rodents to investigators; collection of tissues by center personnel; scheduling at the center for the investigator to perform autopsies and collection of tissues.