Chapter 68 - The Rabbit Model of Bacterial Osteomyelitis of the Tibia

Abstract

This chapter describes the rabbit model of bacterial osteomyelitis of the tibia. New Zealand White rabbits are the species of choice for this model and females weighing 2–3.5 kg and 8–12 weeks in age, are often used because of their low level of aggressive behavior. Once the rabbits arrives at the animal care facility, it is important to wait 7–10 days between arrival and initiation of infection in order to screen for those animals with infections, mainly Pasteurella multocida, but also Clostridium pilaformi, or antibiotic-induced overgrowth of intestinal Gram-negatives. This waiting period is also required for the animals to adjust to their new housing environment, which also makes the animals more relaxed during handling. The strain of S. aureus used in this model was obtained from a patient with osteomyelitis undergoing treatment at the University of Texas Medical Branch. The rabbits are anesthetized by using an intramuscular injection of 45 mg/kg ketamine. An 18G needle is then inserted percutaneously through the lateral aspect of the left tibial metaphysis into the intramedullary cavity. Then 0.15 ml of 5% sodium morrhuate, 0.1 ml of S. aureus (107cfu/ml), and 0.2 ml of sterile 0.85 % saline are injected sequentially. The optimum bacterial inoculum induces a significant localized osteomyelitis within two weeks of infection without a significant increase in mortality for the 6–8 weeks of postinfection survival required for study completion. After saline injection, the needle is removed and the animal is returned to its cage.