Antibiotic Guidelines (NICE compliant 2026)

Based on NICE (NG250 for pneumonia, NG109/113 for UTI, NG141 for SSTI, NG240 for meningitis, NG199 for C. diff), BASHH 2023/24 for STIs, BSAC for endocarditis, and other UK sources like PHE/UKHSA. Always consult local guidelines, BNF, and specialists. Dates reflect latest updates as of 2025.

1. RESPIRATORY TRACT INFECTIONS 🌬️

1.1 Community-Acquired Pneumonia (CAP) 🫁

• Most Common Pathogens:
  • 🟢 S. pneumoniae
  • 🟣 Mycoplasma pneumoniae, Legionella, C. pneumoniae (atypicals)
  • 🟠 H. influenzae (esp. COPD)
• Assessment: CRB-65 score (NICE NG250). 0-1: Outpatient; 2: Hospital; ≥3: Urgent hospital admission.
• Treatment (NICE NG250):
  • 🚶‍♂️ Low severity (outpatient): Amoxicillin 500mg TDS x 5 days. If atypical suspected or penicillin allergy: Doxycycline 200mg day 1, then 100mg OD x 4 days OR Clarithromycin 500mg BD x 5 days.
  • 🏥 High severity (hospital, non-ICU): Co-amoxiclav 1g TDS IV/PO + Clarithromycin 500mg BD. Switch to oral when stable.
  • 💉 Severe/ICU: As above; corticosteroids are **not routinely recommended** except for refractory septic shock or specific indications.
• Duration: 5 days; extend if not improving.

1.2 Hospital-Acquired Pneumonia (HAP) 🎗️

• Pathogens: Gram-negatives (Pseudomonas), MRSA.
• Treatment: Local hospital guidelines. Typical empiric therapy: Pip/taz 4.5g TDS IV. MRSA cover if risk. Start within 1-4 hours. Consult local antibiogram.

1.3 Pharyngitis/Tonsillitis 🤒

• Group A Strep (Centor score ≥3): Phenoxymethylpenicillin 500mg QDS x 10 days. Allergy: Clarithromycin 250mg BD x 5 days.

2. URINARY TRACT INFECTIONS (UTI) 🚽

2.1 Uncomplicated Lower UTI (Cystitis) 💧

• #1 Pathogen: 🟣 E. coli
• Treatment (NICE NG109): Non-pregnant women: Nitrofurantoin 100mg BD x 3 days. Alternatives: Trimethoprim if resistance <20%. Pregnant women: Nitrofurantoin x 7 days (avoid 3rd trimester). Men: 7 days. Back-up prescription if mild.

2.2 Acute Pyelonephritis 🩸

• Treatment (NICE NG109): Ciprofloxacin only if local resistance low and MHRA guidance followed. Alternatives: Co-amoxiclav 500/125mg TDS x 7-10 days OR Cefalexin 500mg QDS x 7-10 days. Monitor renal function and local resistance data.

2.3 Catheter-Associated UTI 🩹

• Treat **only symptomatic patients**. Remove/replace catheter. Typical antibiotics: Ciprofloxacin 500mg BD x 7 days or Co-amoxiclav. Follow NG113.

3. SKIN & SOFT TISSUE INFECTIONS 🩹

3.1 Cellulitis/Erysipelas 🟡

• Pathogens: 🟡 S. aureus, 🔴 S. pyogenes
• Treatment (NICE NG141): Flucloxacillin 500mg QDS x 5-7 days. Severe: IV 1-2g QDS. Allergy: Clarithromycin 500mg BD or Clindamycin 300mg QDS. MRSA risk: Clindamycin or Doxycycline.

3.2 Abscess/Boil 🩸

• I&D primary. Antibiotics if systemic symptoms: Flucloxacillin ± Clindamycin (for MRSA).

3.3 Necrotizing Fasciitis ⚠️

• Urgent surgery + Clindamycin 600-900mg IV TDS + broad-spectrum (e.g., Pip/taz 4.5g TDS).

4. CENTRAL NERVOUS SYSTEM 🧠

4.1 Bacterial Meningitis 💉

• IV antibiotics ASAP (<1h if sepsis). Adults: Ceftriaxone 2g BD. Dexamethasone 10mg IV with/just before first dose if pneumococcal suspected.
• Neonates: Cefotaxime + Ampicillin. Children/Young Adults: Ceftriaxone. Adults >50: add Ampicillin for Listeria.
• Duration: 7-14 days depending on organism.

4.2 Brain Abscess 🩸

• Ceftriaxone 2g BD + Metronidazole 400mg TDS ± Flucloxacillin. Surgery if needed. Duration individualized per organism and surgical outcome.

5. GASTROINTESTINAL INFECTIONS 🤢

5.1 Bacterial Diarrhea 🦠

5.2 Intra-abdominal Infections 🫀

• Pip/taz 4.5g TDS IV or Ceftriaxone 2g OD + Metronidazole 400mg TDS. Source control essential.

6. SEXUALLY TRANSMITTED INFECTIONS 🍆

7. BONE & JOINT INFECTIONS 🦴

7.1 Osteomyelitis 🦴

• Flucloxacillin 1-2g QDS IV. Add Clindamycin if MRSA. Duration: 4-6 weeks total (IV 1-2 weeks, then oral if stable).

7.2 Septic Arthritis 💧

• Urgent aspiration/drainage + Flucloxacillin IV. Gonococcal: Ceftriaxone. Duration: 2-4 weeks IV/PO.

8. ENDOCARDITIS ❤️

• Empiric: Vancomycin + Gentamicin + Flucloxacillin or Pip/taz per local protocol.

9. HIGH-YIELD EMERGENCY ANTIBIOTICS 🎯

• Neutropenic fever: Pip/taz 4.5g TDS IV (or Ceftazidime)
• Meningitis (empiric): Ceftriaxone 2g BD IV + Dexamethasone
• Sepsis (empiric): Pip/taz + Gentamicin (NICE sepsis bundle)
• Bite wounds: Co-amoxiclav 500/125mg TDS x 5 days (NICE NG184)
• Catheters: Vancomycin + remove device if infected

10. RESISTANCE PATTERNS ⚠️

• MRSA: Vancomycin, Daptomycin, Linezolid
• VRE: Linezolid, Daptomycin
• ESBL: Carbapenems (e.g., Ertapenem)
• Pseudomonas: Dual therapy e.g., Ceftazidime + Ciprofloxacin, guided by local antibiogram

11. VECTOR-BORNE & TRAVEL-ASSOCIATED INFECTIONS 🌍

• Lyme Disease (Borrelia burgdorferi) 🐜
  • Transmission: Ixodes tick bite, common in UK rural areas & Europe.
  • Early: Erythema migrans ± flu-like symptoms. Late: arthritis, neuroborreliosis, cardiac involvement.
  • Treatment (NICE NG95): Doxycycline 100mg BD x 21 days (adults). Children <8: Amoxicillin.
  • Investigations: Usually clinical; serology if atypical or late presentation.
• Rickettsial Infections 🦟
  • Examples: African tick bite fever, Rocky Mountain spotted fever (rare in UK but imported cases).
  • Presentation: Fever, rash, eschar at bite site.
  • Treatment (UK guidance, PHE/BNF): Doxycycline 100mg BD adults; children doses adjusted by weight.
• Other Exotic/Tropical Infections 🌴
  • Malaria: Fever ± hemolysis. Diagnosis via blood films/RDT. Treatment depends on species and resistance (UK malaria guidelines, PHE).
  • Leptospirosis: Febrile illness post-freshwater exposure. Mild: supportive; severe: IV penicillin or ceftriaxone.
  • Dengue/Chikungunya/Zika: Supportive therapy. Monitor platelets, liver function, and fluid status.

🩺 KEY TAKEAWAYS FOR UK EXAMS (PLAB/MRCP):
- Antimicrobial stewardship: short courses, de-escalate based on cultures.
- MRSA/Pseudomonas: risk assess (hospitalisation, ICU), consult microbiology.
- Sepsis: antibiotics within 1 hour (NICE NG51).
- Prophylaxis: no routine IE prophylaxis (NICE CG64); focus on hygiene.
- Always: source control + culture-guided therapy. Check BNF for doses.

12. HIGH-CONSEQUENCE & NOTIFIABLE INFECTIONS ⚠️

• Anthrax (Bacillus anthracis) 💀
  • Forms: Cutaneous (most common), inhalational, gastrointestinal.
  • Transmission: Contact with infected animals/products, spores.
  • Treatment (UKHSA/BNF):
    • Cutaneous: Flucloxacillin PO if mild; IV Ciprofloxacin for severe or systemic.
    • Inhalational: Ciprofloxacin ± Doxycycline IV; supportive care intensive.
  • Notify: UKHSA immediately (high-consequence pathogen).
• Plague (Yersinia pestis) 🐀
  • Forms: Bubonic, septicemic, pneumonic.
  • Transmission: Flea bites, contact with animals, respiratory droplets (pneumonic).
  • Treatment (UKHSA): Streptomycin or Ciprofloxacin IV. Isolation for pneumonic plague.
  • Notify: Notifiable; rapid public health action required.
• Tularemia (Francisella tularensis) 🐇
  • Transmission: Contact with wild animals, ticks, aerosols.
  • Clinical: Ulceroglandular most common, fever, lymphadenopathy.
  • Treatment: Gentamicin IV or Ciprofloxacin PO (UK guidance).
  • Notify: Notifiable; rare in UK but possible imported or occupational cases.
• Other rare but exam-relevant pathogens 🌎
  • Botulism (Clostridium botulinum): Flaccid paralysis, supportive care, antitoxin if early.
  • Viral haemorrhagic fevers (Ebola, Marburg): Isolation, notify UKHSA, supportive care.
  • Smallpox: Eradicated but bioterrorism consideration; notify, strict isolation.

💡 UK exam tip: These are extremely rare, but always consider in **severe febrile illness with unusual exposure** or **bioterrorism scenarios**. Early notification and isolation are critical. Remember to consult UKHSA/NICE/BNF guidance for exact dosing and infection control.