What is golden staph and why is a bloodstream infection so serious?

Golden staph refers to Staphylococcus aureus — a bacterium commonly found on the skin and in the nose of healthy people without causing harm. When it enters the bloodstream — after surgery, a catheter insertion, a skin wound, or an infection that spreads — it becomes a bloodstream infection (bacteraemia). This is a medical emergency: untreated, S. aureus bacteraemia carries a 15–25% mortality rate. Treatment requires intravenous antibiotics for several weeks and, in many cases, additional procedures to remove the source of infection. The most common form — MSSA, or methicillin-susceptible S. aureus — responds to a range of antibiotics; the SNAP Trial has now shown that cefazolin is preferable to the traditional first-line agent flucloxacillin.

Will Australian guidelines change as a result of the SNAP Trial?

The SNAP Trial's results are published in the New England Journal of Medicine and The Lancet — two of the most high-profile medical journals — and the findings are sufficiently robust that at least one lead investigator has already switched his personal practice. Australian Therapeutic Guidelines, which currently list cefazolin and flucloxacillin as equal first-line agents for MSSA bacteraemia, will likely be updated as the guidelines committee reviews the evidence. This process takes time — typically months to over a year. In the interim, clinicians aware of the SNAP data can reasonably factor it into their prescribing decisions.

Golden staph: cefazolin now preferred over flucloxacillin in landmark trial

What just happened

The SNAP Trial — the Staphylococcus aureus Network Adaptive Platform Trial — has published its primary findings in The New England Journal of Medicine and The Lancet. With over 150 hospitals across 14 countries, it is the largest clinical trial ever conducted for golden staph bloodstream infections.

The headline finding: for MSSA (methicillin-susceptible Staphylococcus aureus, the most common form of golden staph) bacteraemia, cefazolin is associated with lower 90-day mortality and fewer serious adverse effects than flucloxacillin — the antibiotic currently listed alongside cefazolin as an equal first-line treatment in Australia’s Therapeutic Guidelines.

The Doherty Institute released its summary of the results on 18 June 2026. One of the trial’s lead investigators said he immediately changed his clinical practice.

The both-and

What the trial found

Golden staph bloodstream infections are dangerous. They carry a 15–25% mortality rate globally and contribute to over one million deaths each year. They typically occur in the context of surgery, prosthetic joints, central venous catheters, or skin wounds that allow bacteria to enter the bloodstream — the affected population is broad.

The SNAP Trial compared cefazolin with flucloxacillin for MSSA bacteraemia. The results:

90-day mortality: 15% with cefazolin vs 17% with flucloxacillin. There was an 89% probability that cefazolin was associated with lower mortality.
Acute kidney injury (AKI): 14% with cefazolin vs 20% with flucloxacillin — a clinically meaningful difference in a serious complication.

The trial also examined benzylpenicillin (pen G) against flucloxacillin for infections where the bacteria was susceptible to penicillin (PSSA). For those cases, benzylpenicillin was the superior option.

Professor Steven Tong, an infectious diseases physician at Royal Melbourne Hospital and the Doherty Institute who led the Australian arm of the trial, told the Doherty: “Patients treated with cefazolin fare better, with fewer deaths within 90 days.” He added that the results were sufficiently compelling that he immediately made the switch in his own practice.

What the current guidelines say — and why the gap matters

Australian Therapeutic Guidelines currently lists cefazolin and flucloxacillin as equal first-line treatments for MSSA bacteraemia. The SNAP Trial’s results will need to work through the guidelines committee process before becoming a formal recommendation — but the evidence base is now substantial and peer-reviewed in two top-tier journals.

This is how clinical practice evolves: trials generate evidence, guidelines committees appraise it, prescribing updates follow. The process takes time. In the interim, clinicians who are aware of the SNAP findings can reasonably factor them into decisions for individual patients, particularly where kidney function is already a concern.

The AKI finding is worth dwelling on. Acute kidney injury in the context of a serious systemic infection is not a minor inconvenience — it prolongs hospitalisation, increases overall mortality risk, and can leave lasting impairment to kidney function. If cefazolin produces AKI in 14% of cases versus 20% with flucloxacillin, that is approximately 6 people in every 100 who would have experienced kidney damage and now won’t. At scale, across thousands of hospitalised patients with golden staph annually, that is a clinically significant difference.

What this means for patients

Most people don’t choose which antibiotic their treating team uses for a bloodstream infection. They are in hospital, often seriously unwell, and the prescribing decision is made by the ward or infectious diseases team. That is as it should be — these are complex clinical calls.

But awareness of this trial matters for anyone who might be navigating hospital care for themselves or a family member. Flucloxacillin is not a dangerous antibiotic — it is a well-established drug with decades of use and a well-characterised safety profile. The SNAP Trial does not make it unsafe. What it establishes is that cefazolin is the preferred choice when both options are on the table, on the basis of a mortality and kidney injury signal that is now statistically robust enough for a senior clinician to act on without waiting for guideline revision.

2 cents

If you have a planned admission or procedure where infection risk is elevated — major surgery, joint replacement, cardiac intervention — it is reasonable to ask your surgical team whether the hospital has reviewed its golden staph treatment protocols in light of the SNAP Trial. Most will not yet have formally updated written guidelines. But the question plants a seed, and clinicians who are aware of the evidence will note it.

If you have a family history of kidney disease, or you are already managing reduced kidney function, the AKI findings from this trial are particularly relevant to mention if golden staph bacteraemia ever becomes a treatment decision.

This is one of those trials that will shift practice quietly over the next 12–24 months. The NEJM and Lancet publication makes it high-profile internationally. Guideline bodies and Australian tertiary centres will be watching. By the time Therapeutic Guidelines formally reflects the change, most hospitals with active infectious diseases services will have already moved.

This is general health information and does not constitute individual clinical advice.

Verdict

Verdict: yes — worth knowing about.

The SNAP Trial is the kind of evidence that moves guidelines. It is large, multi-country, with robust primary outcomes in 90-day mortality and kidney injury. For anyone navigating hospital care — particularly anyone with existing kidney disease — knowing that cefazolin is the emerging preferred standard for golden staph bloodstream infection is clinically useful knowledge. And for the general practitioners who will be managing discharge, follow-up, and the questions patients bring back from their hospital stays: this is your briefing.