Ciprofloxacin as therapy for experimental osteomyelitis caused by Pseudomonas aeruginosa.

Ciprofloxacin, a new carboxyquinoline antimicrobial agent, was compared with tobramycin in the treatment of chronic osteomyelitis due to Pseudomonas aeruginosa in rabbits. Treatment with tobramycin for four weeks was ineffective (94% had positive bone cultures). In contrast, ciprofloxacin administered for four weeks sterilized the bones of all but one (94%) of 18 treated rabbits. Treatment with ciprofloxacin for two weeks was less effective than treatment for four weeks but was more effective than either treatment with tobramycin or no therapy. Two of 10 isolates from rabbits treated with ciprofloxacin for two weeks were susceptible to MICs of ciprofloxacin that were 16- and fourfold greater than the MIC for the parent strain; the other eight isolates remained sensitive to ciprofloxacin with MICs equivalent to that of the parent strain.