Rationale and impact
These sections briefly explain why the committee made the recommendations and how they might affect practice. They link to details of the evidence and a full description of the committee's discussion.
The committee agreed that in people with diabetes, all foot wounds are likely to be colonised with bacteria. However, for people with a diabetic foot infection, prompt treatment of the infection is important to prevent complications, including limb-threatening infections.
The committee agreed to retain the recommendation from the 2015 guideline that antibiotics should be started as soon as possible if a diabetic foot infection is suspected. The choice of antibiotic would depend on the severity of infection, although the committee acknowledged that the studies they looked at did not always differentiate between severities. The committee accepted the Infectious Diseases Society of America's definitions of mild, moderate and severe infection, and recommended that this should be taken into account when choosing an antibiotic.
The committee retained the 2015 recommendation that samples should be taken for microbiological testing before, or as close as possible to, the start of antibiotic treatment. This would allow empirical antibiotic treatment to be changed if needed when results are available.
These recommendations are consistent with current practice.
The committee agreed that in their experience, the incidence of diabetic foot infections in children and young people is rare. The mean age of participants in the evidence considered ranged from 54 to 64 years. Based on these factors, the committee included an antibiotic prescribing table for adults, but not for children and young people. They recommended that if a diabetic foot infection is suspected or confirmed in children or young people, specialist advice should be sought regarding antibiotic choice and regimen.
The evidence showed no difference in clinical outcomes for most antibiotics. But the antibiotics used in the studies were not wholly representative of UK practice, with some not being available in the UK and others not widely used. There were no differences in adverse events for many antibiotic comparisons. However, there were differences between some antibiotic classes, with lower rates of adverse effects generally for beta-lactam antibiotics.
The committee agreed that the choice of antibiotic in adults should be based on severity of infection (mild, moderate or severe) and the risk of complications, while minimising adverse effects and antibiotic resistance. This means using narrow-spectrum antibiotics first where possible, and using microbiological results, when available, to guide treatment.
The antibiotics recommended have good activity against many of the pathogens that cause diabetic foot infection, have good penetration for skin and soft tissue infections, and can be used in the different settings where treatment may take place, including ambulatory care. Based on evidence, their experience and resistance data, the committee agreed that flucloxacillin is an effective empirical antibiotic for mild diabetic foot infections (with dosing taking account of a person's body weight and renal function). The committee agreed that flucloxacillin has poor oral bioavailability and in people with diabetes who could have impaired circulation, a higher (off‑label dose) of up to 1 g four times a day may be needed to adequately treat diabetic foot infection.
For adults with a moderate or severe diabetic foot infection, a choice of antibiotics (or combinations of antibiotics) should be available. This enables selection based on individual patient factors, likely pathogens, and guided by microbiological results where available. In moderate and severe infection (which includes osteomyelitis), broader cover is needed because aerobic and anaerobic bacteria may be present. Severe infections can become limb-threatening quickly so antibiotic choices with the broadest spectrum of cover are appropriate; this can be changed to a narrower-spectrum antibiotic based on microbiological results when available, in line with principles of good antimicrobial stewardship. For moderate or severe infection, the committee recommended flucloxacillin at a dose of 1 g four times a day.
Patient preference is also important, particularly for treatment that will involve a hospital stay or be prolonged. Diabetes is a chronic condition and people may have had previous foot infections, with previous courses of antibiotics, that will influence their preferences.
No evidence was identified comparing antibiotic dose, frequency or route of administration. However, the committee acknowledged that a person with a diabetic foot infection may already be on a number of other medications, and this should be taken into account when deciding on dose, frequency and route of administration of an antibiotic.
In line with the NICE guideline on antimicrobial stewardship and Public Health England's Start smart – then focus, the committee agreed that oral antibiotics should be used in preference to intravenous antibiotics where possible. Intravenous antibiotics should only be used for people who are severely ill, unable to tolerate oral treatment, or where oral treatment would not provide adequate coverage or tissue penetration. The use of intravenous antibiotics should be reviewed by 48 hours (taking into account the person's response to treatment and any microbiological results) and switched to oral treatment where possible.
The committee agreed that a shorter course was generally as effective as a longer course for adults with a mild diabetic foot infection, and a 7‑day course was sufficient for most people. However, it agreed that a longer course (up to a further 7 days) may be needed for some people based on a clinical assessment of their symptoms and history. They discussed the limited evidence on antibiotic course length, which compared 6 weeks with 12 weeks in adults with diabetic foot osteomyelitis. The committee agreed that for adults with a moderate or severe diabetic foot infection (which includes osteomyelitis), a 7‑day course would be a minimum, with antibiotic treatment for up to 6 weeks if they have osteomyelitis. When prolonged antibiotic treatment is given, oral options should be used and treatment should be reviewed regularly, taking into account the need for continued antibiotics. The committee discussed antibiotic choices for osteomyelitis and agreed that the empirical choices for moderate and severe diabetic foot infection are also effective empirical choices for osteomyelitis.
The recommendations aim to optimise antibiotic use and reduce antibiotic resistance.
The committee based the recommendation on their experience and safety netting advice from the NICE guideline on antimicrobial stewardship. They agreed that if symptoms worsened rapidly or significantly at any time, or did not improve within 1 to 2 days, people with a diabetic foot infection should be advised to seek medical help.
The recommendation should ensure that appropriate safety netting is in place.
The committee agreed that when microbiological results are available, they should be used to guide antibiotic choice. The committee recognised the complexity around interpreting microbiological results, and agreed that the quality and type of specimen should be taken into account when making decisions around whether to change an antibiotic. The committee also discussed factors that would indicate that a person with a diabetic foot infection would need to be reassessed. These included if an infection was rapidly or significantly worsening or not improving, if other diagnoses were possible, or symptoms suggested a more serious illness or condition.
These recommendations should ensure that appropriate reassessment is in place.
The committee agreed to retain the 2015 recommendation that antibiotics should not be given to prevent diabetic foot infections. No evidence was identified for antibiotic prophylaxis and the committee agreed that antibiotic prophylaxis is not appropriate because of concerns about antimicrobial resistance. People should be advised to seek medical help if symptoms of a diabetic foot infection develop.
This recommendation is consistent with current practice.