Background
Sepsis is a life-threatening condition due to a severe infection. It is a common reason for patients to require life-support . Sepsis is a leading cause of death worldwide. Antibiotics are a major part of the treatment of sepsis, but antibiotics also carry significant risks. The overuse of antibiotics is leading to the emergence of superbugs that can no longer be killed by antibiotics, representing a major global health threat. Antibiotics can also be toxic to organs such as the liver and can occasionally be responsible for life-threatening bowel infections. Striking the right balance of using antibiotics appropriately, while avoiding their potential harm, is a significant challenge. Often if a patient is unwell, without definite evidence of infection, antibiotics will be initiated rapidly because the risk of leaving a potential infection untreated is considered too high. However, once antibiotics are started, the exact duration needed to treat an infection adequately is unknown. International guidelines recommend 7-10 days, but there is little evidence to support this. Studies that have tested different antibiotic durations for specific infections often did not include patients with sepsis. Determining a duration of antibiotics that effectively treats sepsis, but is not unnecessarily prolonged, could have a big impact on antibiotic use overall.

Aim
We aim to determine whether short duration antibiotic treatment is as good as routine practice for critically ill patients with sepsis. Design We will carry out a clinical trial including adult patients with sepsis who are admitted to a critical care unit. We will randomly allocate patients to receive short duration antibiotics, which will be a 5-day course, or usual care (this varies widely in the UK but is typically a 8-day course). This trial will only specify the duration of antibiotics, and the clinical team will know what duration the patient is getting. The choice or combination of antibiotics will be decided by the clinical team. All patients will have antibiotics managed according to normal practice, which will include choosing the antibiotics based on clinical guidelines, the advice of specialists in microbiology, and the results of laboratory tests. The only difference between the two trial groups is that the short duration group will have 5 days of antibiotics. We will determine whether short course antibiotic treatment is as effective as routine practice by assessing clinical outcomes for patients when they are in hospital and at 3-month follow up.