1251. Treatment Outcomes Among Patients With Nosocomial Pneumonia Caused by MRSA Only Versus MRSA Mixed Infections
Session: Poster Abstract Session: Staphylococcal Resistance and Epidemiology
Saturday, October 22, 2011
Room: Poster Hall B1
Handouts
  • ZY11-091 - Treatment Outcomes-IDSA11.pdf (228.7 kB)
  • Background: Methicillin-resistant Staphyloccocus aureus (MRSA) is a pathogen that causes nosocomial pneumonia (NP). NP may be due to MRSA only or MRSA plus a co-pathogen. We analyzed the clinical outcomes and safety among patients with NP caused by MRSA only versus MRSA mixed infections.

    Methods: Data from a prospective, double-blind, randomized clinical trial was analyzed to compare outcomes among patients with NP caused by MRSA only versus MRSA mixed infections treated with linezolid (LZD) 600 mg IV q12h and vancomycin (VAN) 15 mg/kg IV q12h (adjusted for renal function) for 7 to 14 days. Patients with MRSA plus a Gram-negative pathogen received antibiotics with Gram-negative coverage (eg, cefepime) in addition to study drugs. Clinical outcomes, safety, and prevalence of pathogens were compared between patients with MRSA only and MRSA mixed infections by treatment group.

    Results: There were 448 patients included in the analysis, 247 (55%; LZD = 119; VAN = 128) MRSA only and 201 (45%; LZD = 105; VAN = 96) MRSA mixed infections. Clinical success rates were similar for MRSA only versus MRSA mixed infections at both end of treatment (EOT) (74% vs 73%) and end of study (EOS) (53% vs 46%). For MRSA only, clinical success rates were 79.8% and 68.8% (P = 0.07) at EOT and 59.2% and 47.0% (P = 0.08) at EOS for LZD and VAN, respectively. For MRSA mixed infections, clinical success rates were 80.4% and 66.3% (P = 0.04) at EOT and 49.4% and 42.1% (P = 0.36) at EOS for LZD and VAN, respectively. Most MRSA mixed infections were MRSA and Gram-negative pathogens (n = 116 [58%]) followed by MRSA and Gram-positive pathogens (n = 40 [20%]). Adverse events were similar between groups except for MRSA-only infections with respect to nephrotoxicity by treatment (LZD 3.5% vs VAN 20.2%).

    Conclusion: The treatment outcomes were similar for MRSA only versus MRSA mixed infections. The clinical success rates were numerically higher for LZD compared with VAN for NP caused by MRSA only and by MRSA mixed infections at EOT. The majority of mixed infections were MRSA and Gram-negative pathogens. Nephrotoxicity occurs more often with VAN compared with LZD among patients with NP caused by MRSA-only infections.


    Subject Category: C. Clinical studies of bacterial infections and antibacterials including sexually transmitted diseases and mycobacterial infections (surveys, epidemiology, and clinical trials)

    Laura A. Puzniak, PhD, MPH1, Lee Morrow, MD2, Michele Wible1 and David Huang, MD, PhD, MPH3, (1)Pfizer Inc, Collegeville, PA, (2)Creighton University School of Medicine, Omaha, NE, (3)Specialty Care Medicines Development Group, Pfizer Inc, Collegeville, PA

    Disclosures:

    L. A. Puzniak, Pfizer Inc: Employee, Salary

    L. Morrow, None

    M. Wible, Pfizer Inc: Employee, Salary

    D. Huang, Pfizer Inc: Employee, Salary

    Findings in the abstracts are embargoed until 12:01 a.m. EST Thursday, Oct. 20 with the exception of research findings presented at IDSA press conferences.