EFFICACY OF VARIOUS THERAPEUTIC REGIMENS IN ELIMINATING PASTEURELLA-PNEUMOTROPICA FROM THE MOUSE

Pasteurella pneumotropica, a gram-negative opportunistic pathogen, can be isolated from the oropharynx, intestinal tract, and reproductive t ract of clinically normal mice and has been associated with various cl inical syndromes, including conjunctivitis, infections of the reproduc tive tract, otitis, and subcutaneous abscess formation, Enrofloxacin, a fluoroquinolone bactericidal antimicrobial, has been shown to be eff ective in eliminating P. multocida from rabbits, We sought to determin e whether enrofloxacin would eliminate P. pneumotropica from mice know n to be asymptomatically infected with the agent, Pasteurella pneumotr opica-positive (culture and immunofluorescence assay) male (n = 55) an d female (n = 55) C57BL/6N mice mere randomly assigned to one of seven treatment groups or to a control group, These groups were designed to evaluate the efficacy of enrofloxacin administered orally via the dri nking water or parenterally at three dosages (8.5, 25.5, and 85.0 mg/k g of body weight per day) over a 14-day treatment period, A tetracycli ne-treated group (60 mg/kg per day) and an untreated control group wer e included for comparisons, Repeated oropharyngeal swab and fecal spec imens were obtained for culture through posttreatment day 30, and spec imens from numerous enteric and reproductive organs collected during n ecropsy were used to evaluate group differences, Enrofloxacin eliminat ed evidence of P. pneumotropica from all sites when administered at 25 .5 or 85 mg/kg but not at 8.5 mg/kg by either route for at least 30 da ys after treatment, Tetracycline-treated and control groups remained c onsistently culture-positive throughout the study, We concluded that t he oral route may be a more practical method for treating large number s of mice, Enrofloxacin may be a practical and inexpensive alternative to cesarian rederivation or embryo transfer for the elimination of P. pneumotropica in mice.