This prospective observational study puts forward a provocative argument. Many of us are aware that vancomycin being a clunky large molecule has poor tissue penetration especially in the lungs. We are also familiar with the RCT where linezolid bested vancomycin for nosocomial pneumonia. The authors studied children with MRSA pneumonia complicating flu over a 8 year period across 34 pediatric intensive care units from US. 170 children with severe flu requiring ICU admission were enrolled - of them 30 had MRSA pneumonia. Influenza-MRSA pneumonia was associated with increased leukopenia, acute lung injury, vasopressor use, extracorporeal life support, and mortality (P ≤ .0001). Influenza-related mortality was 40% with MRSA compared to 4.3% without (relative risk [RR], 9.3; 95% confidence interval [CI], 3.8-22.9).
Importantly, of 29/30 children with MRSA who received vancomycin within the first 24 hours of hospitalization, mortality was 12.5% (N = 2/16) if treatment also included a second anti-MRSA antibiotic compared to 69.2% (N = 9/13) with vancomycin monotherapy (RR, 5.5; 95% CI, 1.4, 21.3; P = .003). The following figure show the therapy used in the first 24 hours of treatment:
Age, gender, PRISM III score, type of influenza infection, and influenza vaccination did not significantly differ between the early vancomycin monotherapy and the additional early anti-MRSA antibiotic groups. The estimated number needed to treat with more than 1 anti-MRSA agent to prevent 1 death would be 2 (95% CI, 1.2, 3.7). This finding remained significant (P = .01) after adjusting for illness severity in the first 24 hours (PRISM III score) and age.
It may be that combination therapy, or an alternative agent altogether, represents a superior option for management of these high-risk patients.