if methicillin-resistant Staphylococcus aureus [MRSA] is suspected, there are MRSA risk factors, or there is a high incidence of MRSA locally
•Linezolid (600 mg intravenously every 12 hours; may be administered orally when the patient is able to take oral medications).
•Vancomycin (15 to 20 mg/kg [based on actual body weight] intravenously every 8 to 12 hours for patients with normal renal function, with a target serum trough concentration of 15 to 20 mg/L). In seriously ill patients, a loading dose of 25 to 30 mg/kg can be used to facilitate rapid attainment of the target trough concentration.
Duration of therapy
Critical to reducing overuse of antimicrobials, "deescalation" of therapy should be considered after 48 to 72 hours of initial therapy and should be based upon the results of initial cultures and the clinical response of the patient.
The duration of therapy should be based upon the clinical response. A short duration of therapy (eg, seven days) is sufficient for most patients with uncomplicated HAP, VAP, or HCAP who have had a good clinical response.
Linezolid and vancomycin
Several trials have compared linezolid and vancomycin, with variable results:
●A meta-analysis of nine randomized trials that compared linezolid to vancomycin for HAP found no differences in rates of death, clinical response, microbiologic eradication, or MRSA eradication． Linezolid was associated with a higher rate of gastrointestinal adverse effects, but there were no differences in rates of acute kidney injury, thrombocytopenia, or drug discontinuation due to adverse effects.
Treatment of hospital-acquired pneumonia with linezolid or vancomycin: a systematic review and meta-analysis. - PubMed - NCBI
●Another meta-analysis, which included eight trials that compared linezolid to vancomycin or teicoplanin for the treatment of suspected MRSA pneumonia, found no differences in clinical success, microbiologic success, or mortality．
Linezolid vs glycopeptide antibiotics for the treatment of suspected methicillin-resistant Staphylococcus aureus nosocomial pneumonia: a meta-analysi... - PubMed - NCBI
●It should be noted that the studies included in the meta-analyses described above used a dosing regimen for vancomycin that is significantly lower than what is recommended by the ATS and the IDSA．
Guidelines for the management of adults with hospital-acquired, ventilator-associated, and healthcare-associated pneumonia. - PubMed - NCBI
Clinical practice guidelines by the infectious diseases society of america for the treatment of methicillin-resistant Staphylococcus aureus infection... - PubMed - NCBI
Vancomycin therapeutic guidelines: a summary of consensus recommendations from the infectious diseases Society of America, the American Society of He... - PubMed - NCBI
Therapeutic monitoring of vancomycin in adult patients: a consensus review of the American Society of Health-System Pharmacists, the Infectious Disea... - PubMed - NCBI
●In a later randomized double-blind trial that compared linezolid with vancomycin for the treatment of HAP or HCAP due to proven MRSA, the end of study success rate was 58 percent for linezolid and 47 percent for vancomycin． Among patients who had a respiratory specimen available for culture at the end of treatment, 16 of 92 patients (17 percent) who received linezolid had cultures that were persistently positive for MRSA compared with 50 of 109 patients (46 percent) who received vancomycin. In this study, vancomycin dosing was adjusted to achieve target trough levels. Linezolid was noninferior and statistically superior to vancomycin in end of treatment clinical outcome and microbiologic outcome at end of treatment and end of study, but there were no differences in all-cause 60-day mortality or overall adverse events. Nephrotoxicity occurred more commonly with vancomycin than linezolid (18 versus 8 percent).
Linezolid in methicillin-resistant Staphylococcus aureus nosocomial pneumonia: a randomized, controlled study. - PubMed - NCBI
There has been interest in using other agents for the treatment of MRSA pneumonia, but none of the following agents can be recommended: