Core Antimicrobial Guidelines
NICE NG112Active 2023
UTI in Adults
Antimicrobial prescribing for urinary tract infections in adults and young people aged ≥16 years.
- 3-day nitrofurantoin or trimethoprim for cLUTI in women (if local resistance <20%)
- Send MSU before treating if symptoms are atypical or treatment is failing
- Avoid ciprofloxacin unless no alternative — risk of tendon damage, QT prolongation
- Asymptomatic bacteriuria: do not treat (except in pregnancy or pre-urology)
- 7 days for complicated UTI / upper UTI / catheter-associated UTI
NICE NG191Active 2022
Community-Acquired Pneumonia
Antimicrobial prescribing for community-acquired pneumonia in adults and children.
- Low severity CAP (CURB-65 0–1): Amoxicillin 500mg TDS PO for 5 days
- Moderate severity (CURB-65 2): Add clarithromycin for atypical cover
- High severity (CURB-65 ≥3): IV Co-amoxiclav + Clarithromycin; ICU review
- Review at 48h — switch IV to oral when CAPS criteria met
- 5-day course supported for low-moderate severity
NICE NG15Active
Antimicrobial Stewardship
Guidance to ensure antibiotics are used in a way that minimises the development of resistance.
- Document indication, dose, route, duration, and review date on ALL antibiotic prescriptions
- Conduct a formal antibiotic review at 48–72 hours
- De-escalate from broad-spectrum to narrow-spectrum on the basis of culture results
- Use the shortest effective course — avoid long empirical courses
- Apply IV to oral switch early using CAPS criteria
NICE NG51Time Critical
Sepsis Recognition & Management
Sepsis: recognition, diagnosis and early management in adults, young people and children.
- Sepsis Six within 1 hour: O₂, bloods/lactate, blood cultures, IV fluids, antibiotics, urine output
- Antibiotics within 1 hour of recognition — every hour's delay increases mortality
- Take blood cultures before antibiotics (but do not delay antibiotics >45 min for cultures)
- De-escalate on the basis of 48h culture results and clinical response
- qSOFA ≥2: high risk of adverse outcome — escalate urgently
NICE NG109Active 2020
Cellulitis & Erysipelas
Antimicrobial prescribing for cellulitis and erysipelas in adults and young people.
- First-line: Flucloxacillin 500mg–1g QDS PO (fasting) or IV for 5 days (extend if not improving)
- Penicillin allergy (mild): Clarithromycin or Doxycycline
- Penicillin allergy (severe): Clindamycin or discuss with Microbiology
- MRSA-colonised: Doxycycline or Co-trimoxazole (seek micro advice)
- Mark margins and reassess at 24–48h; admit if systemically unwell
ESCMID 2021Active 2021
Clostridioides difficile Infection
European Society of Clinical Microbiology and Infectious Diseases guidelines for CDI management.
- First episode: Fidaxomicin 200mg BD for 10 days (preferred) or Vancomycin PO 125mg QDS for 10 days
- Metronidazole no longer recommended as first-line therapy
- Stop precipitating antibiotics where clinically safe to do so
- Infection control: contact precautions, soap and water (alcohol gel ineffective against spores)
- CDI is a mandatory reportable infection — notify infection control immediately
Scoring System Reference
| Score | What It Assesses | Key Threshold | Action |
|---|---|---|---|
| NEWS2 | Acute illness severity / deterioration | ≥5 (medium risk) / ≥7 (high risk) | Urgent senior review / Critical care |
| CURB-65 | Pneumonia severity (30-day mortality) | 0–1 (home) / 2 (hospital) / ≥3 (ICU) | Escalate treatment intensity |
| qSOFA | Sepsis-related organ failure risk | ≥2 = high risk | Initiate Sepsis Six, escalate urgently |
| Wells DVT | Pre-test probability of DVT | ≥3 high (75%) / 1–2 moderate / <1 low | Direct imaging and anticoagulation pathway |
| CRB-65 | Pneumonia severity (community/primary care) | 0 (home) / 1–2 (hospital consider) / 3–4 (urgent) | Used in primary care when urea unavailable |
Duration of Therapy Quick Reference
| Infection | Recommended Duration | Guideline | Notes |
|---|---|---|---|
| cLUTI (women, uncomplicated) | 3 days | NICE NG112 | Nitrofurantoin: 5–7 days |
| Upper UTI / Pyelonephritis | 7–10 days | NICE NG112 | Review on sensitivities |
| CAP (low severity) | 5 days | NICE NG191 | Extend if no improvement at 3 days |
| CAP (moderate-severe) | 7–10 days | BTS | IV→oral switch when CAPS met |
| Cellulitis (mild-moderate) | 5 days minimum | NICE NG109 | Extend if not improving at 48h |
| MSSA bacteraemia | 14 days minimum IV | BSAC | Daily blood cultures until clear |
| MRSA bacteraemia | 14 days minimum IV | BSAC / ID input | Echo, ID review mandatory |
| Endocarditis (native valve) | 4–6 weeks IV | ESC 2023 | Organism and valve dependent |
| Osteomyelitis (acute) | 6 weeks total (IV + oral) | BSAC | ID/orthopaedics input |
| Meningitis (Pneumococcal) | 10–14 days | NICE / ESCMID | Dexamethasone adjunct |
| C. difficile (1st episode) | 10 days | ESCMID 2021 | Fidaxomicin preferred |
External Resources & Links
BNF Online
British National Formulary — doses, interactions, contraindications
bnf.nice.org.uk →
NICE Guidelines
Full NICE guidance library — infection, stewardship, sepsis
nice.org.uk/guidance →
BSAC Guidelines
British Society for Antimicrobial Chemotherapy — endocarditis, bone/joint
bsac.org.uk/guidelines →
PHE ESPAUR
English surveillance programme — antimicrobial utilisation and resistance
gov.uk/espaur →
ESCMID Guidelines
European guidelines including CDI, MRSA, fungal infections
escmid.org/guidelines →
NEWS2 / RCP
National Early Warning Score 2 — Royal College of Physicians
rcplondon.ac.uk/news2 →
UK Sepsis Trust
Sepsis Six toolkit, training resources, patient information
sepsistrust.org →
BTS Pneumonia
British Thoracic Society — CAP guidelines and management
brit-thoracic.org.uk →
🔗 Important: Always verify with your local trust antimicrobial formulary and consult your microbiology or infectious diseases team for complex prescribing decisions. Guidelines are regularly updated — always check for the current version.