What oral therapy would you choose?

Based on the story in step 1.6, which of the following is your preferred management strategy now (in a low MRSA endemicity environment)?

a) Oral Flucloxacillin 1g every 6 hours for 3 – 5 days

b) Oral Doxycycline 100mg every 12 hours for 3 – 5 days

c) Oral Linezolid 600mg every 12 hours for 3 – 5 days

d) Stop antibiotic therapy; no oral switch

The case represents a relatively common clinical dilemma in OPAT practice: is ongoing oral therapy required?

The patient appears to have responded very favourably to 5 days of IV antibiotics and it is likely that the causal bacteria are now either dead or able to be dealt with by the host’s immune system.

Any remaining symptoms and signs are more likely to represent residual inflammation (which can last for many weeks in some infections, including cellulitis) rather than persisting infection that requires ongoing antibiotics.

There is an increasing evidence-base to support short rather than longer courses of antibiotics in infection practice.

However, it should be noted that the DANCE trial, which compared 6 versus 12 days of antibiotics for severe cellulitis in predominantly older patients with comorbid conditions (e.g. 24% diabetes), found that while early cure (at 14 and 28 days) were similar for short and longer course therapy, 90-day relapse was statistically significantly higher with a 6-day course (23.5% versus 6%). Careful patient selection for short-course therapy may therefore be required.

One approach to such dilemmas in the OPAT environment is shared-decision making. Choosing Wisely UK, which aims to optimise conversations between patients and their healthcare professionals and minimise overuse of medical intervention, suggests considering the following questions in any discussion with your patient:

1. What are the Benefits?

2. What are the Risks?

3. What are the Alternatives?

4. What if I do Nothing?

If further oral therapy is chosen then any of the suggested agents (a to c) are potentially suitable, although one could strongly question the appropriateness of using Linezolid in a non-MRSA environment from an antimicrobial stewardship perspective.

Whilst doxycycline is convenient from the adherence perspective and has good anti-MSSA (and MRSA) activity in the UK, it is not as reliable against Lancefield group A, C or G streptococci.

Flucloxacillin has a more reliable susceptibility profile in a low MRSA setting, but has poor oral bioavailability and needs to be taken four times daily; this may not matter in this situation, however, as the patient has improved considerably.

Other antibiotics that, depending on circumstances, may be appropriate include Co-trimoxazole and Clindamycin. The latter has a higher risk of adverse effects, including Clostridium difficile infection.

Locally, we would very likely discontinue antibiotic therapy in this situation.