What is the appropriate management for a patient with an arteriovenous graft who develops Staphylococcus aureus bacteremia?

Management of AV Graft with Staphylococcus aureus Bacteremia

An infected arteriovenous graft with S. aureus bacteremia requires both systemic antibiotic therapy AND surgical removal of the infected graft material—antibiotics alone will not cure the infection because the synthetic graft acts as a foreign body that prevents infection resolution. 1

Immediate Antibiotic Management

• Start empiric IV antibiotics immediately covering both Gram-negative and Gram-positive organisms (including MRSA and Enterococcus) before culture results return 1
• Vancomycin or daptomycin should be the initial empiric choice given the high likelihood of MRSA in dialysis patients and the virulence of S. aureus in graft infections 2, 3
• Once susceptibilities are known, switch to cefazolin or antistaphylococcal penicillin for methicillin-susceptible S. aureus (MSSA), or continue vancomycin/daptomycin for MRSA 2
• Continue antibiotics for a minimum of 14 days after graft removal, with longer courses (4-6 weeks) if bacteremia persists beyond 48 hours after source control or if metastatic infection is present 1, 2

Surgical Management: Graft Removal is Mandatory

The critical distinction here is that infected AV grafts (synthetic) require surgical removal, unlike infected AV fistulas (native vessels) which can often be salvaged with antibiotics alone. 4, 5

Extent of Graft Excision

• Total graft excision (TGE) is preferred over partial graft excision (PGE) because TGE has significantly lower reinfection rates 6
• Research shows reinfection occurs in 31% of patients after partial excision versus significantly lower rates with total excision 7, 6
• For extensive infection with systemic signs (bacteremia, sepsis, fever), total graft removal is mandatory 1, 5
• For localized infection without systemic involvement, incision and resection of the infected portion may be attempted, but carries higher reinfection risk 1, 7
• Do not leave any retained graft material, as subclinical infection from retained synthetic material causes persistent inflammation, epoetin resistance, and ongoing bacteremia 1, 5

Timing of Intervention

• Graft removal should be performed urgently, ideally within 36 hours if the patient remains symptomatic despite antibiotics 1
• Do not delay removal in unstable patients—clinical instability mandates immediate graft excision regardless of antibiotic response 1

Evaluation for Metastatic Infection

S. aureus bacteremia causes metastatic infection in over one-third of cases, making comprehensive evaluation essential 2:

• All patients require transthoracic echocardiography to evaluate for endocarditis 2, 3
• Transesophageal echocardiography is mandatory for patients with persistent bacteremia beyond 48-72 hours, persistent fever, or any implantable cardiac devices 2, 3
• Obtain imaging (CT or MRI) based on symptoms to evaluate for vertebral osteomyelitis (4% incidence), spinal epidural abscess, septic arthritis (7% incidence), or other deep-seated infections 2
• Repeat blood cultures periodically during treatment and immediately after completing antibiotics to confirm clearance 1, 4

Post-Removal Access Management

• A temporary central venous catheter will be required after graft removal, with median duration of 90 days before new access creation 7
• Blood cultures must be negative for at least 48 hours after completing antibiotics before placing any new permanent access 1, 4
• Only 52% of eligible patients receive new definitive access within the first year after infected graft removal 8
• Close follow-up is essential to reassess for potential new access creation, as many patients remain catheter-dependent long-term 8

Critical Pitfalls to Avoid

• Do not attempt to salvage an infected synthetic graft with antibiotics alone—this approach fails because the foreign body prevents infection resolution 1, 5
• Do not confuse management of infected grafts versus infected fistulas—native fistulas can usually be treated with 6 weeks of antibiotics without removal, but synthetic grafts require excision 4
• Do not perform partial excision in abandoned (non-functioning) grafts—these have approximately 2-fold higher reinfection rates and should undergo total excision 6, 5
• Do not underestimate the morbidity—36% of patients experience postoperative complications, 30% are readmitted within 30 days, and 55% within 90 days 8
• Do not place new permanent access prematurely—wait until blood cultures are definitively negative after completing the full antibiotic course 1, 4