Global clinical trial on treating common bloodstream infection launches in the UK

29 Nov 2023

The SNAP trial, which investigates the best way to treat bloodstream infections caused by Staphylococcus aureus bacteria, opened in the UK this week. 

SNAP is the largest ever clinical trial in S. aureus bloodstream infection, taking place in the UK, Australia, New Zealand, Canada, Singapore, The Netherlands, South Africa and Israel. The MRC Clinical Trials Unit leads on trial management and statistical analysis within the UK and UCL is the trial's UK sponsor.

After two years of regulatory delays, the first UK participant joined the trial on 27th November 2023 at University College London Hospitals. Two more UK sites also opened at Oxford University Hospitals and Hull University Teaching Hospitals. 

S. aureus normally lives harmlessly on the skin or in the nose. But if the bacteria enter the blood through a cut or sore, they can multiply and cause a bloodstream infection – sometimes called bacteraemia. This can be very serious or even life-threatening. The infection can affect many parts of the body including the lungs, heart, bones and muscles.

S. aureus bloodstream infections are common, and many different antibiotics can be used to treat them effectively. However, researchers and clinicians are unsure which of these treatments is best.

SNAP will evaluate a range of different antibiotic treatments for three different types of S. aureus infection (penicillin-susceptible, methicillin susceptible and methicillin-resistant).  

This large, international trial is made up of three domains: 

  • Antibiotic backbone domain: Participants are randomly allocated to receive one of two possible backbone antibiotics for each type of S. aureus infection. 
  • Adjunctive treatment domain: Participants are randomly allocated to receive either clindamycin (a medicine which prevents S. aureus from producing toxins that damage the body) in addition to a backbone antibiotic, or a backbone antibiotic only with no clindamycin. 
  • Early oral switch domain: All participants begin their antibiotic course intravenously. After seven days, those who are improving quickly are randomly allocated to either continue the course intravenously or switch to an oral antibiotic for the duration of the course. Those who are not well enough after seven days will continue taking antibiotics intravenously until day 14, where, if their condition has improved, they will be randomised to either stay on intravenous treatment or switch to oral antibiotics. 

SNAP is funded by the National Institute for Health and Care Research and is expected to run until 2027. 

Further information: