LONG THERAPY AND SIDE EFFECTS IN ORTHOPAEDIC INFECTIONS CAUSED BY METHICILLIN-RESISTANT STAPHYLOCOCCUS SP.

Abstract

Severe periprothetic joint infections require a very long treatment. Gram positive microorganisms are an important source of infection in this area. Methicillin–resistant Staphylococcus produces a great number of cases. In this situation a long and effective therapy is required, and Linezolid appears to be an oral alternative. We are concerned about the adverse reactions in 28-day or longer therapy, as gastrointestinal, neuropathics, thrombocytopenia, anaemia and pancytopenia.

The purpose of the study was to observe the efficacy and adverse reactions in periprothetic joint infections that were treated with Linezolid intravenously and orally in our area.

We recorded the clinical and laboratory data of the patients with severe periprothetic joint infections from January to December 2006 at Hospital Clinico San Carlos, Madrid. The inclusion criteria for treatment with Linezolid were: methicillin– resistant Staphylococcus isolates in more than three samples, no contraindication of treatment, and long therapy indicated.

Sixteen patients were included, of whom 11 were women and 5 men. The mean age was 77.8 years (44–82). The infections were located in 10 knees and 6 hip protheses. 11 methicillin-resistant Staphylococcus aureus and 5 methicillin-resistant coagulase-negative Staphylococcus were isolated. Linezolid was administered for a mean of 4.35 months (2–9). For the hip periprothetic infection the treatment lasted 2.5 to 9 months (mean: 3.6 months), and for the knee periprothetic infection 4 to 6 months (mean: 5 months). The infection was ruled out at the end of the treatment in all cases. Just in one case, thrombocytopenia occurred as an adverse event, in a patient treated with linezolid for 2.5 months. Thrombocytopenia reverted when treatment was stopped.

In severe periprothetic joint infections by methicillin-resistant Sthaphylococcus sp. Linezolid is a good choice of treatment. It is an effective antibiotic and its posology makes its use easy and reliable. It is necessary to keep on studying its safety in long therapy clinical trials.