Monday, June 30, 2014

Linezolid in MRSA pneumonia: does it protect against tissue damage?

The debate concerning linezolid versus vancomycin as first line treatment for MRSA pneumonia is ongoing. This paper reports a mouse model of MRSA pneumonia in which linezolid may have a unique direct anti-inflammatory effect:

Results. Significant antibacterial activity was achieved after 48 hours of treatment for linezolid and vancomycin. Levels of interleukin 1β, a major proinflammatory cytokine, and macrophage inflammatory protein 2, a chemokine involved in the recruitment of neutrophils, were decreased by both antimicrobials. Only linezolid was able to dramatically reduce the production of tumor necrosis factor α. Analysis of myeloperoxidase activity and Ly6G immunostaining showed a dramatic decrease of neutrophil infiltration in infected lung tissues for linezolid-treated animals. A time-dependent increase of endothelial permeability was observed for the control and vancomycin regimens. Of interest, in the linezolid group, decreased endothelial permeability was detected 48 hours after infection.

Conclusions. Our results indicate that linezolid could be superior to vancomycin for the management of MRSA pneumonia by attenuating an excessive inflammatory reaction and protecting the lung from pathogen-associated damages.

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