What is the primary approach to managing bacterial infections that require endothelial support?

Management of Bacterial Infections Requiring Endothelial Support

The primary approach to managing bacterial infections that require endothelial support is prompt catheter removal combined with appropriate systemic antimicrobial therapy targeted at the specific pathogen. 1

Initial Assessment and Diagnosis

When bacterial infection with endothelial involvement is suspected:

1. Obtain appropriate cultures before initiating antibiotics:

   • Two sets of blood cultures (one percutaneously, one from the catheter) 1
   • Use paired quantitative blood cultures or qualitative cultures with differential time to positivity 1

2. Evaluate for septic thrombosis and endocarditis:

   • Perform transesophageal echocardiography (TEE) for patients with Staphylococcus aureus bacteremia 1
   • TEE is superior to transthoracic echocardiography for detecting vegetations 1

Management Algorithm Based on Pathogen

For Staphylococcus aureus:

1. Remove the catheter in all cases of S. aureus bacteremia 1
2. Antimicrobial therapy:
   • First choice: β-lactam antibiotics for methicillin-susceptible S. aureus (MSSA) 1
   • For methicillin-resistant S. aureus (MRSA): vancomycin or daptomycin 2
   • Do not use vancomycin for β-lactam-susceptible S. aureus as it has higher failure rates and slower clearance of bacteremia 1
3. Duration of therapy:
   • 14 days if TEE is negative and catheter is removed 1
   • 4-6 weeks if endocarditis or septic thrombosis is present 1, 2

For Gram-negative Bacilli:

1. Remove non-tunneled catheters in all cases 1
2. Antimicrobial therapy:
   • 10-14 days of appropriate antimicrobial therapy 1
   • For Pseudomonas aeruginosa: include anti-pseudomonal coverage, especially in neutropenic patients 1
   • Quinolones (e.g., ciprofloxacin) with or without rifampin may be preferred for oral therapy 1
3. Consider catheter salvage only for tunneled catheters without organ dysfunction, hypoperfusion, or hypotension 1

For Candida and Other Fungi:

1. Remove all catheters with documented fungemia 1
2. Antifungal therapy:
   • Amphotericin B for hemodynamically unstable patients or those with prior fluconazole exposure 1
   • Fluconazole for stable patients with susceptible organisms 1
   • Duration: 14 days after last positive blood culture and resolution of symptoms 1

Management of Septic Thrombosis

When septic thrombosis is present:

1. Remove the involved catheter in all cases 1
2. Use heparin for septic thrombosis of great central veins and arteries 1, 2
3. Surgical intervention:
   • Incision, drainage, and excision of infected peripheral veins when there is suppuration or persistent bacteremia 1
   • Surgical exploration when infection extends beyond the vein 1
4. Extended antimicrobial therapy (4-6 weeks) for septic thrombosis of great central veins 1, 2

Persistent Bacteremia and Endocarditis

For patients with persistent bacteremia:

1. Remove the catheter in all cases of persistent bacteremia 1
2. Treat presumptively for endovascular infection if blood cultures remain positive or clinical status unchanged 3 days after catheter removal 1
3. Duration of therapy: 4 weeks of antimicrobial therapy in most cases 1
4. Consider surgical intervention for endocarditis with large vegetations, embolic events, or severe valvular insufficiency 2

Catheter Reinsertion

1. For non-tunneled catheters: May be reinserted after appropriate systemic antimicrobial therapy is begun 1
2. For tunneled catheters: Postpone reinsertion until after appropriate antimicrobial therapy is begun and repeat blood cultures are negative 1

Prevention Strategies

For high-risk patients requiring long-term catheters:

1. Consider prophylactic antimicrobial locks in facilities with high rates of catheter-related bloodstream infections 1
2. Weekly prophylactic thrombolytic agent locking (recombinant TPA) may be beneficial 1

Common Pitfalls to Avoid

1. Failure to remove infected catheters in cases of persistent bacteremia, tunnel infection, or fungemia 1
2. Inadequate duration of therapy for complicated bacteremia or endovascular infections 2
3. Using vancomycin for β-lactam-susceptible S. aureus infections 1
4. Failure to obtain appropriate cultures before initiating antibiotics 1
5. Missing endovascular complications by not performing TEE in S. aureus bacteremia 1

By following this algorithm, clinicians can effectively manage bacterial infections requiring endothelial support, reducing mortality and preventing complications such as endocarditis and septic thrombosis.