MRSA Research Today is a free monthly online journal that collates and summarizes the latest research about MRSA, including details on methicillin-resistant staphylococcus aureus, hospitals, infection, antibiotic resistance, superbugs.

Linezolid tissue penetration and serum activity against strains of methicillin-resistant Staphylococcus aureus with reduced vancomycin susceptibility in diabetic patients with foot infections.

Stein GE, Schooley S, Peloquin CA, Missavage A, Havlichek DH

Michigan State University-School of Medicine, B320 Life Science Building, East Lansing, MI 48824, USA.

Objectives Linezolid soft tissue penetration and serum antimicrobial activity were analysed in six patients with peripheral vascular disease and severe diabetic foot infections requiring surgical intervention. Methods Blood draws (1, 3, 6, 9 and 12 h after initiation of a 1 h infusion) and a viable soft tissue sample at the site of infection were obtained in patients receiving linezolid (600 mg every 12 h) on the day of surgery. Concentrations of linezolid were determined by HPLC in both tissue (pre-treated with tissue lysis buffer) and serum. In addition, serum inhibitory and bactericidal activity (dilution titres 1:2-1:32) of linezolid was determined in these patients against strains of methicillin-resistant Staphylococcus aureus (MRSA) with reduced susceptibility to vancomycin (vancomycin MICs = 2, 4, 8, 256 and >256 mg/L). Results Linezolid concentrations in tissue were found to be 51% (range, 18% to 78%) of simultaneous serum concentrations. Rapid (1 h) and prolonged (12 h) inhibitory activity (titres >/= 1:2) was observed for linezolid against each of the study isolates. Furthermore, bactericidal activity (titres >/= 1:2) was observed for at least 6 h (50% of the dosing interval) against four of these five strains. Conclusions These findings suggest that linezolid could be effective in the treatment of multidrug-resistant MRSA even when concentrations at the infection site are diminished due to impaired blood flow.

Published 14 September 2007 in J Antimicrob Chemother, 60(4): 819-23.
Full-text of this article is available online (may require subscription).

© 2004-2008 MRSA Research Today. All Rights Reserved.