Long-term use of daptomycin for MRSA osteomyelitis and joint infection

Over 870 days of successful antibiotic suppression therapy for VRE-infected left ventricular assist device

Left ventricular assist devices (LVADs) are used in patients with advanced heart failure. Infections are common complications following device placement; however, the efficacy of chronic antimicrobial suppression therapy for deep-seated infections is not well characterized. We report the case of a 49-year-old male with a HeartMate II LVAD who presented with a methicillin-sensitive Staphylococcus aureus pump pocket infection that was subsequently treated with antibiotics and HeartMate III pump exchange. A vancomycin-resistant Enterococcus faecium (VRE) pump pocket infection then developed and responded to surgical drainage followed by long-term suppression with daptomycin then linezolid for over 870 days. A second pump exchange was not required. To our knowledge, this represents the longest reported use of daptomycin (341 days) without symptomatic adverse events. Managing infections caused by multidrug-resistant pathogens presents a clinical challenge. This case demonstrates the potential for antimicrobial suppression therapy to allow for successful retention of a VRE-infected LVAD.

New approaches for treating staphylococcal biofilm infections

Bacteria of the genus Staphylococcus are a prominent cause of acute and chronic infections. The ability of the staphylococci to establish biofilms has been linked to the persistence of chronic infections, which has drawn considerable interest from researchers over the past decade. Biofilms can be defined as sessile communities of surface-attached cells encased in an extracellular matrix, and treatment of bacteria in this mode of growth is challenging due to the resistance of biofilm structures to both antimicrobials and host defenses. In this review of the literature, we introduce Staphylococcus aureus and Staphylococcus epidermidis biofilms and summarize current antibiotic treatment approaches for staphylococcal biofilm infections. We also review recent studies on alternative strategies for preventing biofilm formation and dispersing established biofilms, including matrix-degrading enzymes, small-molecule approaches, and manipulation of natural staphylococcal disassembly mechanisms. While research on staphylococcal biofilm development is still in its early stages, new discoveries in the field hold promise for improved therapies that target staphylococcal biofilm infections.

New therapeutic choices for infections caused by methicillin-resistant Staphylococcus aureus

In recent years, a marked increase in the incidence of infections caused by methicillin-resistant Staphylococcus aureus (MRSA) has occurred in many countries. This review addresses the effectiveness and limitations of drugs classically used for the treatment of MRSA, e.g. vancomycin, and also newer anti-MRSA antimicrobials, e.g. second-generation glycolipopeptides, tigecycline, and beta-lactams.

Daptomycin in bone and joint infections: a review of the literature

INTRODUCTION

To review the pharmacology, pharmacokinetics, efficacy, and safety of daptomycin, a novel antibiotic for the treatment of bone and joint infections, a literature search of relevant articles was conducted.

MATERIALS AND METHODS

A PubMed/MEDLINE search (1990-April 2008) to identify relevant English-language literature was conducted. Search terms included bone and joint infection, osteomyelitis, daptomycin, and methicillin-resistant Staphylococcus aureus (MRSA). Additional articles were identified by reviewing the bibliographies of articles cited. Programs and abstracts from infectious disease meetings were searched, and prescribing information of antibiotics indicated for bone and joint infections consulted. All articles identified from data sources published in English were evaluated.

RESULTS

Caused primarily by Gram-positive pathogens such as S. aureus and, to a lesser extent, Enterococcus faecalis, bone and joint infections are difficult to treat successfully. Surgical intervention and prolonged courses of antibiotics are frequently required, and failure of first-line antibiotic therapy is common. The emergence of S. aureus strains with reduced susceptibility to vancomycin, the longstanding gold standard for bone and joint infections, has complicated the clinical scenario. Few randomized trials comparing the efficacy of different antibiotics for bone and joint infections exist. Daptomycin, a novel intravenous lipopeptide antibiotic, has shown potent in vitro activity against a broad spectrum of Gram-positive bacteria, including many resistant pathogens commonly associated with bone and joint infections such as MRSA and vancomycin-resistant E. faecalis. Early clinical investigation of daptomycin in bone and joint infections unresponsive to antibiotics, such as vancomycin, has found a cure rate of approximately 80%, with a low incidence of adverse events and drug resistance.

CONCLUSION

Further studies are warranted to determine if limited clinical evidence, described in individual case reports and a daptomycin-specific retrospective registry, suggests daptomycin is a promising option for patients with bone and joint infections such as MRSA osteomyelitis.