Common use of the empirical combination of vancomycin and a β-lactam for staphylococcal bacteremia.

TO THE EDITOR—The recent discussion by McConeghy et al of treatment for staphylococcal bacteremia using an empirical combination of vancomycin and a βlactam was insightful [1]. They and other investigators have speculated that using initial empirical coverage with activity against bothmethicillin-resistant Staphylococcus aureus and methicillin-susceptible S. aureus (MSSA) may lead to improved clinical outcomes [2, 3]. Empirical antibacterial coverage including vancomycin and β-lactam antibiotics with significant coverage for gram-negative pathogens has been reported with varying frequency [4, 5]. At our institution, we frequently encounter patients with a variety of indications (sepsis, fever, skin and skin structure infections, pneumonia, and others) who are receiving empirical therapy with vancomycin plus either piperacillin/tazobactam or cefepime. In discussions with multiple infectious disease physicians across the nation, we have commonly heard similar anecdotal observations, although published data in this regard are limited. β-Lactam agents such as piperacillin/ tazobactam and cefepime may offer significant coverage for MSSA as well as for gram-negative organisms [6, 7]. Although these β-lactam antibiotics may not usually be considered as antistaphylococcal drugs as are nafcillin, oxacillin, and cefazolin, their antistaphylococcal activity may already be achieving the objective as suggested by McConeghy et al [1]. Current clinical practice may thus have already accomplished part of the goal McConeghy et al outlined. We caution as well that pressure related to the goal of antimicrobial stewardship may lead to premature de-escalation to vancomycin monotherapy before susceptibility results are known, leading to less desirable clinical outcomes.