What are the recommendations for perioperative antibiotics in a liver transplant patient, particularly with consideration of the Model for End-Stage Liver Disease (MELD) score?

Perioperative Antibiotic Prophylaxis in Liver Transplantation with MELD Score Considerations

For liver transplant recipients, a single dose of intravenous antibiotics should be administered within 60 minutes before skin incision, with targeted prophylaxis for patients colonized with multidrug-resistant organisms, particularly those with high MELD scores (>24). 1

Standard Antibiotic Prophylaxis Recommendations

• A single dose of intravenous antibiotics should be administered within 60 minutes before skin incision for liver transplantation 1
• Standard prophylaxis typically consists of a first-generation cephalosporin such as cefazolin 1
• Postoperative "prophylactic" antibiotics beyond 24 hours are not recommended for routine cases without biliary reconstruction 1
• For complex liver surgery with biliary reconstruction, a targeted antibiotic pre-emptive regimen based on preoperative bile culture may be beneficial 1

MELD Score Considerations for Antibiotic Prophylaxis

• Patients with MELD scores >24 are considered at higher risk for developing multidrug-resistant (MDR) infections and may require modified antibiotic prophylaxis 1
• Risk factors for targeted prophylaxis include: pretransplant colonization with resistant organisms, treatment with broad-spectrum antibiotics in the past 30 days, need for dialysis, or MELD score >24 1
• In patients with high MELD scores (≥20), there is an increased risk of postoperative infections, which may influence the choice of perioperative antibiotics 2

Special Considerations for Colonized Patients

• For patients colonized with extended-spectrum β-lactamase-producing Enterobacterales (ESCR-E), targeted perioperative antibiotic prophylaxis is conditionally recommended 1
• Rectal screening to identify ESCR-E carriers before liver transplant surgery is conditionally recommended according to local epidemiology 1
• For patients colonized with carbapenem-resistant Enterobacterales (CRE), there is insufficient evidence to recommend for or against targeted prophylaxis 1
• Implementation of screening procedures should follow assessment of local prevalence of resistant organisms among patients admitted to surgical wards 1

Specific Antibiotic Regimens

• For standard prophylaxis: cefazolin or ceftriaxone alone is appropriate for most patients 3
• For patients colonized with ESCR-E: consider carbapenems (e.g., ertapenem), but limit use if other options are available 1
• For patients with high MELD scores and additional risk factors: consider amikacin in association with ampicillin 1
• Reserve antibiotics such as ceftazidime-avibactam, ceftolozane-tazobactam, and other novel agents for treatment rather than prophylaxis 1

Pitfalls and Caveats

• Deep surgical site infections (SSIs) occur in approximately 15% of liver transplant recipients despite prophylaxis, with a median onset of 13.5 days post-transplant 4
• Up to 53% of bacteria causing SSIs may be multidrug-resistant, including 95% of Enterococcus faecium and 55% of Enterobacteriaceae 4
• The most common pathogens in liver transplant SSIs are Enterobacteriaceae (42%), Enterococcus spp. (24%), and Candida spp. (15%) 4
• Recent evidence suggests that the spectrum of antimicrobial prophylaxis (narrow vs. broad) may not significantly impact the development of SSIs in liver transplant recipients 3
• Surgical complications such as bile leaks and reoperations are stronger independent risk factors for SSIs than the choice of prophylactic antibiotics 3

Practical Approach

1. Assess patient's risk factors:

   • MELD score (>24 indicates higher risk) 1
   • Previous colonization with resistant organisms 1
   • Recent broad-spectrum antibiotic use 1
   • Need for dialysis 1
   • Complexity of planned procedure (biliary reconstruction) 1

2. Select appropriate prophylaxis:

   • Standard risk: Single dose of cefazolin within 60 minutes before incision 1
   • High risk or ESCR-E colonized: Consider targeted prophylaxis with appropriate coverage 1
   • Complex biliary reconstruction: Consider targeted regimen based on preoperative bile culture 1

3. Avoid unnecessary prolonged prophylaxis:

   • Limit duration to 24 hours in uncomplicated cases 1
   • Consider extending to 48 hours only for complex biliary reconstruction 1

4. Monitor for surgical complications that increase infection risk:

   • Bile leaks 4, 3
   • Need for reoperation 3

Despite variations in practice across transplant centers 5, 6, the evidence supports a targeted approach to perioperative antibiotic prophylaxis in liver transplantation, with special consideration for patients with high MELD scores and those colonized with resistant organisms.