When Professor Steven Tong reviewed the latest results from the SNAP Trial, he didn’t wait for guidelines to change—he changed his prescription pad that same day. The international clinical trial, the largest of its kind for golden staph bloodstream infections, has delivered a clear verdict: flucloxacillin, long considered the default treatment, should no longer be the go-to antibiotic. Instead, cefazolin and benzylpenicillin have emerged as safer, equally effective alternatives, offering new hope for patients battling one of the world’s deadliest infections.
Golden staph, or Staphylococcus aureus, kills more than 1 million people globally each year. When it enters the bloodstream, mortality ranges from 15% to 25%, making treatment decisions critical. For decades, flucloxacillin has been the standard of care, especially for methicillin-susceptible strains (MSSA), despite growing concerns about side effects. The SNAP Trial, spanning over 150 hospitals across 14 countries and led by the Peter Doherty Institute and the University of Newcastle, was designed to cut through uncertainty by rapidly testing real-world treatment strategies.
The results, published in the New England Journal of Medicine and The Lancet, are transformative. In the NEJM study comparing cefazolin and flucloxacillin for MSSA, patients on cefazolin had a 15% death rate within 90 days—lower than the 17% seen with flucloxacillin—and a significantly reduced risk of acute kidney injury (14% vs. 20%). The data showed an 89% probability that cefazolin leads to lower mortality, prompting Professor Tong to declare, “I immediately made the switch in my own clinical practice.”
Equally striking was the Lancet study’s finding on benzylpenicillin for penicillin-susceptible strains (PSSA). Once abandoned due to rising resistance, penicillin is now making a comeback—when susceptibility is confirmed. Patients treated with benzylpenicillin had a 14% mortality rate compared to 22% with flucloxacillin, along with fewer kidney complications. “Benzylpenicillin was as effective as flucloxacillin and likely safer,” said Professor Todd Lee, co-lead investigator from McGill University.
These findings don’t just refine treatment—they redefine it. By validating older, safer antibiotics, the trial challenges decades of clinical habit and opens the door to more personalized, lab-guided therapy. With antibiotic resistance a growing global threat, using the right drug—not just any effective one—has never been more important. As hospitals around the world absorb these results, one truth is clear: sometimes, the best medical advances aren’t about new drugs, but rediscovering the ones we already have.