Derivation of Pasteurella multocida-free rabbit litters by enrofloxacin treatment

Pasteurella multocida is an important bacterial pathogen of rabbits that is easily transmitted from infected does to their kits prior to weaning. Enrofloxacin, a flouroquinolone antibiotic, is effective at limiting nasal carriage of P. multocida in rabbits. To determine if enrofloxacin treatment of pregnant does infected with P. multocida can be used to produce P. multocida-free litters, groups of 3 rabbits were inoculated intranasally on day 10 of gestation with 1.0 x l0⁶ P. multocida CFUs. Beginning on day 14, one group received enrofloxacin IM (5 mg kg^-1 BID), and a second group received enrofloxacin in the drinking water (200 mg l^-1). IM treatment continued until kindling, while PO treatment continued 1 week after kindling. A third group was infected but received only IM saline, and a fourth group was infected but not treated. In addition, a fifth group was neither infected nor treated. Culture of nasal lavage samples and tissues from does and kits showed that both routes of enrofloxacin treatment failed to completely eliminate P. multocida from does, but all kits from enrofloxacin-treated does were free from P. multocida. These results suggest that treatment of does with enrofloxacin during the periparturient period may interrupt transmission of P. multocida from infected does to their kits and that this treatment may be useful for deriving Pasteurella-free rabbits from infected does.