Rat Model of Chronic Pseudomonas aeruginosa Lung Infection

Publisher Summary This chapter presents a rat model of chronic Pseudomonas aeruginosa lung infection. No specific pretreatment is required for this model, except that the animals should acclimatize at least 5–6 days before surgery and be kept under good conventional conditions with no more than three individuals in each cage. The rats are sedated with an i.p. injection of 1.5 ml/kg body weight of a 1:1 mixture of etomidate and midazolam. Complete anesthesia ensues in about 10 minutes and lasts for about 1 hour. The anesthetized rats are surgically tracheotomized, and the intratracheal challenge with 0.1 ml of P. aeruginosa embedded in alginate beads is installed in the lower part of the left lung with a curved, bead-tipped needle. The head of the rat should be in a slightly elevated position to ease respiration. The wound is closed by using synthetic, green-braided, polyglycolic acid, sterile, absorbable surgical suture, 3-0 Dexon 'S' CE-6, 24 mm cutting. The rats are kept warm after surgery by placing them under paper towels until they begin to recover from the anesthetic. The infection is confined to the lung. Most of the rats experience an increase of approximately 0.5o C in rectal temperature during the first day after operation. Deaths due to sepsis are rare, however, despite the fact that some animals have temporary bacteraemia. Body weight gain and food and water intake are similar to normal animals, and the mortality rate in chronically infected rats is approximately 10–16%.