1 Infectious Diseases Unit and 2 Service of Orthopaedic Surgery, San Cecilio University Hospital, Granada, Spain
Keywords: prosthetic joint infections, glycopeptides, quinupristin-dalfopristin, linezolid
Sir,
We have read with interest the article by Bernard et al.1 and would like to comment on some aspects. The ideal regimen and the optimal duration of antibiotics for a favourable outcome have not been clearly defined in any randomized controlled trial. But, because the isolates most frequently recovered in prosthetic joint infection (PJI) are Staphylococcus spp.and among them methicillin-resistant staphylococci are becoming more frequent2glycopeptide antibiotics (vancomycin and teicoplanin) are usually used as first-line therapy for PJI. Empirical therapy should not rely on quinolones, as Bernard et al.1 stated. However, the overuse and, occasionally, the inappropriate use of glycopeptide antibiotics have led to the emergence of glycopeptide-intermediate staphylococci strains.3 In this context, effective alternative regimens are needed. Quinupristindalfopristin (Synercid), the first injectable streptogramin antibiotic, has demonstrated consistent in vitro activity against a variety of Gram-positive organisms, including methicillin-resistant staphylococci, and has a role in the treatment of PJI alone or in combination with rifampicin4 with high efficacy rates.
Linezolid, the first synthetic oxazolidinone to become available, has a broad spectrum of in vitro activity against Gram-positive organisms, including methicillin-resistant staphylococci. It has a unique mechanism of action, which means that there is no cross-resistance with other classes of antimicrobial agents.5 Similarly, as with quinupristindalfopristin, linezolid has demonstrated high efficacy rates in the treatment of PJI.6 However, the great advantage of linezolid is that the drug is available in both intravenous and oral formulations, the latter exhibiting 100% bioavailability, which makes this antibiotic an attractive option for prolonged treatments. The main concern of therapy with linezolid is that its prolonged use is associated with myelosuppression, but given linezolids efficacy for treating serious Gram-positive infections, activity against resistant pathogens and equivalent intravenous-to-oral formulations, the benefits of linezolid treatment may outweigh the potential risk of reversible myelosuppression. Neither alternative is mentioned in the article by Bernard et al.1 We believe that any article that intends approaching PTI therapy has to mention all the possible antimicrobial alternatives, and clearly state that the mainstays of therapy are glycopeptides, at least until well-designed trials show evidence of greater benefit of other agents.
Footnotes
* Correspondence address. Infectious Diseases Unit, San Cecilio University Hospital, Avda. Dr. Oloriz s/n, 18012 Granada, Spain. Tel: +34-958-023104; Fax: +34-958-249079; E-mail: jordi{at}ugr.es
References
1
.
Bernard, L., Hoffmeyer, P., Assal, M. et al. (2004). Trends in the treatment of orthopaedic prosthetic infections. Journal of Antimicrobial Chemotherapy 53, 1279.
2 . Centers for Disease Control and Prevention. (1999). National Nosocomial Infection Surveillance (NNIS) System report, data summary from January 1990 to May 1999, issued June 1999. American Journal of Infection Control 27, 52032.[ISI][Medline]
3
.
Smith, T. L., Pearson, M. L., Wilcox, K. R. et al. (1999). Emergence of vancomycin resistance in Staphylococcus aureus. New England Journal of Medicine 340, 493501.
4
.
Saleh-Mghir, A., Ameur, N., Muller-Serieys, C. et al. (2002). Combination of quinupristin-dalfopristin (Synercid) and rifampin is highly synergistic in experimental Staphylococcus aureus joint prosthesis infection. Antimicrobial Agents and Chemotherapy 46, 11224.
5
.
Moellering, R., Jr (2003). Linezolid: the first oxazolidinone antimicrobial. Annals of Internal Medicine 138, 13542.
6
.
Moise, P. A., Forrest, A., Birmingham, M. C. et al. (2002). The efficacy and safety of linezolid as treatment for Staphylococcus aureus in compassionate use patients who are intolerant of, or who have failed to respond to, vancomycin. Journal of Antimicrobial Chemotherapy 50, 101726.
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