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β-lactam or Vancomycin First for Bacteremia?

November 17, 2021

Written by Vivian Lei

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Administration of a β-lactam before vancomycin in patients with bloodstream infections (BSI) is protective against 48-hour and 7-day mortality.

Why does this matter?
Early antibiotic administration is a cornerstone of sepsis management, but the sequence of antibiotic administration has received less attention. This study supports giving a β-lactam as the first dose antibiotic as opposed to vancomycin – a practice which has a great deal of face validity since β-lactams have broader coverage, can be infused faster, and cover pathogens that tend to be associated with higher mortality.

Order of operation matters
This was a retrospective, observational study of patients age 13 years and older hospitalized with a bacterial BSI who received both a β-lactam agent and vancomycin, assessing whether sequence of administration impacted mortality. 3,376 patients were included in the analysis over a 4 year period. Of these patients, 2,685 (79.5%) received a β-lactam agent before vancomycin while 691 (20.5%) received vancomycin before a β-lactam. The most common β-lactam agents were piperacillin-tazobactam (47.9%), cefepime (42.0%), and meropenem (5%). Administration of a β-lactam agent prior to administration of vancomycin was protective against 7-day mortality with an adjusted OR of 0.48 (95%CI: 0.22-0.69) as well as 48 hour mortality with an aOR of 0.45 (95%CI 0.24-0.83). Of those patients with MRSA bacteremia, administration of β-lactam prior to vancomycin did not offer any protective 7-day mortality benefit (aOR 0.93 [95%CI 0.33-2.63]) but neither did administering vancomycin first.

Given the large number of BSI each year, the researchers posit that “prioritizing initial β-lactam has the potential to save 737 lives per year, underscoring the significant impact of a relatively simple practice change.”

Limitations: This study was retrospective in design, so there may be other variables that impacted which antibiotic was chosen for administration first. It also does not account for any antibiotics administered before blood culture collection.

Administration of a β-lactam Prior to Vancomycin as the First Dose of Antibiotic Therapy Improves Survival in Patients with Bloodstream Infections. Clin Infect Dis. 2021 Oct 4;ciab865. doi: 10.1093/cid/ciab865. Online ahead of print.

What are your thoughts?