Prolonged treatment of chronic Pseudomonas aeruginosa osteomyelitis with a combination of two effective antibiotics.

Emergence of Pseudomonas aeruginosa resistant to antibiotic monotherapy is one of the causes of therapeutic failure in chronic P. aeruginosa osteomyelitis. We report 15 cases of chronic (> 3 months of evolution) biopsy culture proven P. aeruginosa osteomyelitis included in an open prospective study evaluating the efficacy of prolonged treatment (> 4 months) with two effective antibiotics in combination. Mean post-treatment follow-up was 38 months. A regimen of cefsulodin in combination with oral ofloxacin was used for six patients, cefsulodin-pefloxacin for three patients, cefsulodin-ciprofloxacin for one patient, piperacillin-pefloxacin for one patient, cefsulodin-fosfomycin for one patient, imipenem-ciprofloxacin for two patients and amoxicillin-ciprofloxacin-fosfomycin for one patient as home therapy. The clinical cure rate of 73% and bacteriological cure rate of 93% are far superior to those previously described in the literature. We did not observe adverse drug reactions. We think that a prolonged use of two effective antibiotics in combination is a safe and improved therapeutic schedule for chronic P. aeruginosa osteomyelitis.