Severe Sepsis - Unknown Focus (Antimicrobial)
TAM (Treatments and Medicines) NHS Highland
What's new / Latest updates
28/09/26 V3: reviewed and approved by AMT 10/09/26
- In penicillin allergy, AKI, hospital-acquired infection: due to long-term supply issue, aztreonam has been replace by ciprofloxacin in this treatment recommendation. Reminder to assess MHRA risks before prescribing fluoroquinolones.
02/07/25 - added hyperlink to necrotising fasciitis.
Seek microbiology advice. Review regime regularly in light of evolving clinical picture.
Review within 24 hours to confirm diagnosis, then follow appropriate infection specific recommendations.
If sepsis has a cutaneous component or is arising from the skin, REFER TO SECTION ON NECROTISING FASCIITIS (under skin/soft tissue infections).
Drug details
Community-acquired infection
IV amoxicillin 1g every 6 hours PLUS IV gentamicin - refer to NHS Highland gentamicin dosing guidelines PLUS IV metronidazole 500mg every 8 hours.
Duration - according to diagnosis.
If Staphylococcus aureus infection suspected
ADD IV flucloxacillin 2g every 6 hours
Duration - according to diagnosis.
In penicillin allergy, severe renal impairment, acute kidney injury or hospital-acquired infection
IV ciprofloxacin 400mg IV every 8 hours or as per Renal Drug Database (see BNF warnings and MHRA Drug Safety Alert (updated 22 January 2024))
PLUS IV vancomycin - refer to NHS Highland vancomycin guidelines
PLUS IV metronidazole 500mg 3 times daily
Duration - according to diagnosis.