Linezolid Alone or Combined With Carbapenem Against Methicillin-resistant Staphylococcus Aureus (MRSA) in Ventilator-associated Pneumonia

Linezolid Alone or Combined With Carbapenem Against Methicillin-resistant Staphylococcus Aureus (MRSA) in Vitro and in Ventilator-associated Pneumonia

As previous studies showed that the synergy between linezolid and carbapenem in vitro and in vivo (animal studies), our study is aim to investigate the activity of linezolid, alone and in combination with carbapenem against methicillin-resistant Staphylococcus aureus (MRSA) in ventilator-associated pneumonia (VAP) patients.

Linezolid is the only commercially available oxazolidinone, the first new class of antibiotic to be developed in the last three decades. Although it is predominantly bacteriostatic, linezolid has good in vitro and in vivo activity against MRSA . However, several studies did not show that linezolid was superior to any of glycopeptides in treatment of MRSA pneumonia. Moreover, combination therapy against MRSA is argued when several in vitro and in vivo studies showed synergy between linezolid and carbapenem or fosfomycin or rifampicin, while vancomycin and linezolid in combination should be avoided. our study is aim to investigate the activity of linezolid, alone and in combination with carbapenem against methicillin-resistant Staphylococcus aureus (MRSA) in ventilator-associated pneumonia (VAP) patients.

Inclusion Criteria:

• Pneumonia, Ventilator-associated

  • the presence of new or persistent radiographic features
  • fever higher than 38°C
  • leukocytosis (≥11.0 ×109/L) or neutropenia (≤3.5×109/L)
  • purulent endotracheal
  • increasing oxygen requirements

• Endotracheal aspiration culture show methicillin-resistant S. aureus positive

Exclusion Criteria:

• immunocompromised patients (postorgan transplantation or human immunodeficiency virus-infected or neutropenic [≤1×109/L absolute neutrophils], or patients receiving corticosteroids >20 mg/d for 6 months)
• colonized chronically with methicillin-resistant S. aureus
• pregnancy
• endotracheal aspiration culture showed no MRSA