Treatment Considerations for Empiric Therapy
Bruce Jones, PharmD, FIDSA, BCPS offered clinical considerations for the concerns around infective endocarditis and when choosing empiric therapy.
Contagion: Staph aureus bacteremia remains a serious infection that can lead to infective endocarditis, and a higher mortality rate. With this in mind, what do you want to consider in treatment options?
Jones: When I think of Staphylococcus aureus, I think of a pathogen with metastatic tendencies; it often spreads to distant sites and tends to form abscesses. For us, we used to assume MRSA until proven otherwise if S aureus was in our differential. Around 2015, things changed with the introduction of multiplex PCR—specifically Biofire at our institution—which was a game-changer for managing bacteremia. This tool allows us to quickly identify MRSA versus MSSA, and even detect S aureus itself very early on, which helps guide treatment decisions upfront.
Another key point I emphasize is beginning with the end in mind, particularly regarding OPAT. Many of these patients will need 4 to 6 weeks of treatment, so from a discharge and OPAT perspective, it's crucial to make these decisions early, ideally well before discharge. Often, we tend to wait until the last moment, but it’s better to evaluate these factors early in the admission.
Contagion: What are your clinical considerations when choosing an empiric therapy for these patients?
Jones: Clinical stability is our top priority. For a very sick patient in the ICU on multiple pressors, we approach aggressively upfront, as Staphylococcus aureus infections carry a high mortality rate. Our goal is to get the infection under control as quickly as possible.
We also consider the suspected source of the infection. For example, when MRSA is suspected, if it's a respiratory source, we might avoid using daptomycin. Comorbidities play a big role as well; renal function is one of the first things we assess, especially when considering vancomycin in patients with acute kidney injury or chronic kidney disease.
Once we know whether it's MSSA or MRSA—thanks to rapid diagnostics—we tailor treatment accordingly. For MSSA, cefazolin or an antistaphylococcal penicillin is our go-to. For MRSA, we often consider vancomycin or daptomycin, though we've used less vancomycin in the past year or two and more daptomycin instead. While our use of linezolid has been slower to increase, it's still an option. We're also starting to see some off-label use of ceftaroline, and with the release of septiviprol, we’ll soon have another tool in our toolkit.
The conversation was edited for grammar and clarity.
