Similar hematologic effects of long-term linezolid and vancomycin therapy in a prospective observational study of patients with orthopedic infections.

Linezolid is an alternative to vancomycin for the long-term treatment of gram-positive bacterial orthopedic infections because of its antibacterial spectrum and oral bioavailability, but duration-related myelosuppression could offset its advantages. To evaluate the hematologic effects of these agents, we prospectively studied 65 consecutive adults with gram-positive bacterial orthopedic infections requiring > or =2 weeks of vancomycin therapy (n=52) or linezolid therapy (n=20). Trends suggesting higher incidence of hematologic effects among the patients receiving vancomycin were not significant, regardless of whether the end point was lowest cell count during therapy or change from baseline. The only difference was a higher incidence of thrombocytopenia (<150x10(9) platelets/L) in the subset of the linezolid recipients who had received vancomycin within 2 weeks before starting linezolid therapy than in the linezolid recipients who had not received vancomycin (5 [71%] of 7 patients vs. 2 [15%] of 13; P=.02). All hematologic effects were reversible. In conclusion, hematologic effects were detectable through weekly monitoring and were reversible; therefore, concern about myelosuppression need not preclude linezolid use for orthopedic infections requiring long-term therapy.

Successful treatment of chronic bone and joint infections with oral linezolid.

Linezolid is an attractive alternative for the treatment of chronic bone and joint infections because it is active against common pathogens including methicillin-resistant staphylococci and vancomycin-resistant enterococci and because its oral formulation is convenient for long-term administration. To evaluate the ability of linezolid to produce long-term remission, we prospectively monitored 11 consecutive adult patients who received linezolid for osteomyelitis (n = 9) or prosthetic joint infection (n = 2). Linezolid 600 mg was administered orally twice daily for a mean of 10 weeks (range, 6 to 19 weeks). Pathogens were methicillin-resistant Staphylococcus aureus (n = 5), methicillin-resistant coagulase-negative staphylococci (n = 4), vancomycin-resistant Enterococcus faecium (n = 1), and vancomycin-sensitive Enterococcus faecalis (n = 1). After a mean followup of 27 months (range, 17 to 41 months), all 11 patients had remission by clinical, laboratory, and radiographic criteria. During week 8 of linezolid treatment, one patient developed a gram-negative superinfection, which resolved with appropriate therapy. During week 6 of linezolid treatment, one patient developed mild thrombocytopenia and another patient developed mild anemia. Both episodes of myelosuppression were reversible within 10 days after completing the planned 6-week courses of linezolid. We recommend weekly complete blood counts to detect hematologic abnormalities. We conclude that oral linezolid seems to be a useful and convenient alternative for the treatment of bone and joint infections.