Role for newer beta-lactam antibiotics in treatment of osteomyelitis.

Monotherapy of osteomyelitis with the newer broad-spectrum beta-lactam antibiotics has become attractive because of the efficacy, safety, and cost of these antibiotics when compared with conventional combination therapy. Imipenem/cilastatin is a recent and promising addition to this antibiotic family. Experience with imipenem/cilastatin and that reported for cefotaxime, ceftazidime, and ceftizoxime in the treatment of biopsy-proved osteomyelitis was compared, using data from published reports from five centers. Two hundred forty-three patients were evaluable: 34 were treated with imipenem/cilastatin, 84 with cefotaxime, 122 with ceftazidime, and 33 with ceftizoxime. Staphylococcus aureus was isolated by 80 bone cultures and was the most common single species encountered. There were 75 isolates of Pseudomonas aeruginosa, 113 mixed Enterobacteriaceae species, 115 mixed gram-positive and -negative isolates of miscellaneous species, and 30 anerobic isolates. Polymicrobial infection was present in 101 cases (41.6 percent). Failure rates were similarly low in all groups (10 to 30 percent). However, resistance developed during therapy in all groups with P. aeruginosa. Side effects were predictably few, but reversible neutropenia, pseudomembranous colitis due to Clostridium difficile, and nausea required therapy to be discontinued in seven patients. Imipenem/cilastatin should prove to be a very effective and relatively safe single agent for treatment of osteomyelitis.