Quick reference algorithm

Open Fracture — Antibiotic Prophylaxis

Adult trauma patients with open fractures · 2026 edition

Antibiotics as early as possible — ideally ≤ 1 hInstitutional guideline TRM_GUI.0031

Open fracture identified — ED arrival

Give antibiotics as early as possible — ideally ≤ 1 h.

Do not delay for imaging or transfer.
Update tetanus.
Classify Gustilo–Anderson type.

Two questions drive the regimen

β-lactam allergy?
Gustilo type + contamination (soil/fecal or standing water)?

Then add vancomycin if known MRSA colonization.

Empiric regimen by fracture type · per TRM_GUI.0031

Type I / II

Lower-energy, ≤ 10 cm wound

Cefazolin 2 g IV q8h (3 g if > 120 kg)

Clindamycin 900 mg IV q8h

Type III — clean

High-energy / > 10 cm

Ceftriaxone 2 g IV q24h

Clindamycin 900 mg IV q8h

+ Levofloxacin 500 mg IV q24h

Type III + soil / fecal

Gross organic contamination

Ceftriaxone 2 g IV q24h

+ Metronidazole 500 mg IV q8h

Clindamycin + Levofloxacin (clindamycin covers anaerobes) † not in policy

Type III + standing / open water

Fresh, salt, or brackish water

Piperacillin–tazobactam 4.5 g IV q8h † see water note

Ciprofloxacin 400 mg IV q12h — consult ID / pharmacy † not in policy

Vancomycin — add for known MRSA colonization

Vancomycin 15 mg/kg IV q12h — added to any regimen above for documented MRSA colonization.
Pharmacy-dosed; see evidence note on AUC-guided dosing.

Duration

Type I / II: 24 hours.
Type III: continue until 24 h after final wound closure.
No added benefit beyond 24 h post-closure, even for Type III.

Evidence notes — beyond the institutional guideline; current evidence, confirm locally before use

Water exposure: piperacillin–tazobactam (per policy) covers Aeromonas (fresh / brackish water). For saltwater or brackish wounds, current ID guidance also favors Doxycycline 100 mg IV/PO q12h + a 3rd-gen cephalosporin (e.g., ceftazidime) for Vibrio vulnificus.
Vancomycin: AUC-guided dosing is now preferred over trough targets (ASHP/IDSA 2020) — dose per pharmacy.
Timing: earliest antibiotic administration (≤ 1 h) is the factor most strongly associated with reduced infection.
β-lactam allergy with contaminated Type III: regimen not specified in policy — consult ID / pharmacy.

Concurrent care

Tetanus prophylaxis per immunization status.
Irrigation & debridement — urgent; emergent for gross contamination or vascular compromise.
Plan definitive soft-tissue coverage (target ≤ 5–7 days).
Re-dose intraoperative antibiotics per blood loss / duration.

Gustilo–Anderson classification (reference)

Type	Wound	Soft tissue	Contamination
I	< 1 cm	Minimal damage	Clean
II	1–10 cm	Moderate damage, no flap	Moderate
IIIA	> 10 cm	Adequate coverage possible	High energy
IIIB	> 10 cm	Requires flap / graft coverage	Severe
IIIC	Any	Vascular injury requiring repair	Variable

Empiric regimen by fracture type · per TRM_GUI.0031

Type I / II

Lower-energy, ≤ 10 cm wound

Cefazolin 2 g IV q8h (3 g if > 120 kg)

Clindamycin 900 mg IV q8h

Type III — clean

High-energy / > 10 cm

Ceftriaxone 2 g IV q24h

Clindamycin 900 mg IV q8h

+ Levofloxacin 500 mg IV q24h

Type III + soil / fecal

Gross organic contamination

Ceftriaxone 2 g IV q24h

+ Metronidazole 500 mg IV q8h

Clindamycin + Levofloxacin (clindamycin covers anaerobes) † not in policy

Type III + standing / open water

Fresh, salt, or brackish water

Piperacillin–tazobactam 4.5 g IV q8h † see water note

Ciprofloxacin 400 mg IV q12h — consult ID / pharmacy † not in policy

Evidence notes — beyond the institutional guideline; current evidence, confirm locally before use

Water exposure: piperacillin–tazobactam (per policy) covers Aeromonas (fresh / brackish water). For saltwater or brackish wounds, current ID guidance also favors Doxycycline 100 mg IV/PO q12h + a 3rd-gen cephalosporin (e.g., ceftazidime) for Vibrio vulnificus.

Vancomycin: AUC-guided dosing is now preferred over trough targets (ASHP/IDSA 2020) — dose per pharmacy.

Timing: earliest antibiotic administration (≤ 1 h) is the factor most strongly associated with reduced infection.

β-lactam allergy with contaminated Type III: regimen not specified in policy — consult ID / pharmacy.

Type

Wound

Soft tissue

Contamination

< 1 cm

Minimal damage

Clean

1–10 cm

Moderate damage, no flap

Moderate

IIIA

> 10 cm

Adequate coverage possible

High energy

IIIB

> 10 cm

Requires flap / graft coverage

Severe

IIIC

Any

Vascular injury requiring repair

Variable