Ambulatory treatment of multidrug-resistant Staphylococcus-infected orthopedic implants with high-dose oral co-trimoxazole (trimethoprim-sulfamethoxazole)

We examined the effectiveness and safety of high-dose oral co-trimoxazole ( trimethoprim-sulfamethoxazole) for the treatment of orthopedic implants inf ected with multidrug-resistant Staphylococcus species. The prospective stud y was conducted between 1989 and 1997 in a university medical center with a mbulatory-care services. Patients eligible for the study consisted of those from whom multidrug-resistant Staphylococcus spp. organisms susceptible on ly to glycopeptides and co-trimoxazole mere isolated from their orthopedic implants and for whom there was no contraindication to the treatment. All p atients were treated orally with high-dose co-trimoxazole (trimethoprim, 20 mg/kg of body weight/day; sulfamethoxazole, 100 mg/kg/day). Patients with prosthetic hip infections were treated for 6 months, with removal of any un stable prosthesis after 5 months of treatment; patients with prosthetic kne e infections were treated for 9 months, with removal of any unstable prosth esis after 6 months of treatment; and patients with infected osteosynthetic devices were treated for 6 months, with removal of the device after 3 mont hs of treatment, if necessary. Monthly clinical evaluations were conducted until the completion of the treatment, and follow-up examinations were cond ucted regularly for up to 6 years. The overall treatment success rate was 6 6.7% (26 of 39 patients), with success rates of 62.5% for patients with pro sthetic knee infections, 50% for those with prosthetic hip infections, and 78.9% for those with other device infections. Seventeen of the 28 (60.7%) p atients who did not have any orthopedic material removed were cured. Eight patients stopped the treatment because of side effects, and one patient was not compliant. In three patients treatment failed because of the appearanc e of a resistant bacterium. Long-term oral ambulatory treatment with co-tri moxazole appears to be an effective alternative to the conventional medicos urgical treatment of chronic multidrug-resistant Staphylococcus-infected or thopedic implants which includes long-term intravenous antibiotic therapy c ombined with surgical debridement and removal of foreign material or its su bsequent one- or two-stage replacement.