Linezolid limits burden of methicillin-resistant Staphylococcus aureus in biofilm of tracheal tubes

Crit Care Med. 2012 Aug;40(8):2385-9. doi: 10.1097/CCM.0b013e31825332fc.


Objective: To evaluate the effects of systemic treatment with linezolid compared with vancomycin on biofilm formation in mechanically ventilated pigs with severe methicillin-resistant Staphylococcus aureus-induced pneumonia.

Design: Prospective randomized animal study.

Setting: Departments of Pneumology, Microbiology, and Pharmacy of the Hospital Clínic, Barcelona, and Scientific and Technological Services of the University of Barcelona.

Subjects: We prospectively analyzed 70 endotracheal tube samples. Endotracheal tubes were obtained from pigs either untreated (controls, n=20), or treated with vancomycin (n=32) or linezolid (n=18).

Interventions: The endotracheal tubes were obtained from a previous randomized study in tracheally intubated pigs with methicillin-resistant Staphylococcus aureus severe pneumonia, and mechanically ventilated for 69±16 hrs.

Measurements and main results: Distal and medial hemisections of the endotracheal tube were assessed to quantify methicillin-resistant Staphylococcus aureus burden, antibiotic biofilm concentration by high-performance liquid chromatography or bioassay, and biofilm thickness through scanning electron microscopy. We found a trend toward a significant variation in biofilm methicillin-resistant Staphylococcus aureus burden (log colony-forming unit/mL) among groups (p=.057), and the lowest bacterial burden was found in endotracheal tubes treated with linezolid (1.98±1.68) in comparison with untreated endotracheal tubes (3.72±2.20, p=.045) or those treated with vancomycin (2.97±2.43, p=.286). Biofilm linezolid concentration was 19-fold above the linezolid minimum inhibitory concentration, whereas biofilm vancomycin concentration (1.60±0.91 µg/mL) was consistently below or close to the vancomycin minimum inhibitory concentration. Biofilm was thicker in the vancomycin group (p=.077).

Conclusions: Systemic treatment with linezolid limits endotracheal tube biofilm development and methicillin-resistant Staphylococcus aureus burden. The potential clinical usefulness of linezolid in decreasing the risk of biofilm-related respiratory infections during prolonged tracheal intubation requires further investigation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetamides / therapeutic use*
  • Animals
  • Anti-Bacterial Agents / therapeutic use*
  • Biofilms / drug effects*
  • Intubation, Intratracheal / adverse effects*
  • Linezolid
  • Methicillin-Resistant Staphylococcus aureus / drug effects*
  • Microscopy, Electron, Scanning
  • Oxazolidinones / therapeutic use*
  • Pneumonia, Staphylococcal / drug therapy
  • Pneumonia, Ventilator-Associated / drug therapy*
  • Swine
  • Vancomycin / therapeutic use


  • Acetamides
  • Anti-Bacterial Agents
  • Oxazolidinones
  • Vancomycin
  • Linezolid