What is the best approach to manage a catheter-related blood infection in a patient?

Management of Catheter-Related Bloodstream Infection

The management of catheter-related bloodstream infection requires immediate blood cultures from both the catheter and peripheral vein, followed by empirical antibiotic therapy with vancomycin (or cefazolin in low-MRSA settings) plus gram-negative coverage, with catheter removal decisions based on catheter type, pathogen, and clinical severity. 1

Initial Assessment and Diagnostic Approach

Obtain blood cultures immediately from both the catheter and a peripheral vein before starting antibiotics, and culture any purulent drainage from the exit site for Gram stain. 2, 1, 3 Do not routinely remove catheters in patients with fever and mild-to-moderate disease without additional concerning features. 2

Remove the catheter immediately if:

• Severe sepsis or hemodynamic instability is present 1
• Erythema or purulence overlies the catheter exit site 2
• Clinical signs of sepsis are evident 2
• The infection involves S. aureus, Candida species, Pseudomonas (non-aeruginosa), Bacillus, Corynebacterium, or mycobacteria 1
• Complicated infections exist, including septic thrombosis, endocarditis, or metastatic infection 1
• Persistent bacteremia continues despite appropriate antibiotics 1

Empirical Antibiotic Therapy

Gram-Positive Coverage

Start vancomycin as the cornerstone of empirical therapy in healthcare settings with elevated MRSA prevalence. 1 In institutions where MRSA isolates have vancomycin MIC values >2 μg/mL, use daptomycin instead (6 mg/kg IV once daily for adults). 1, 4

In units with low MRSA prevalence, substitute cefazolin for vancomycin to avoid promoting vancomycin resistance. 1

Gram-Negative Coverage

Add gram-negative coverage based on local antimicrobial susceptibility data and disease severity. 1 Use fourth-generation cephalosporins (cefepime), carbapenems, or β-lactam/β-lactamase combinations, with or without aminoglycosides. 1

For neutropenic patients, severely septic patients, or those colonized with multidrug-resistant organisms, use empirical combination therapy for Pseudomonas aeruginosa until culture results allow de-escalation. 1

Special Situations

For femoral catheters in critically ill patients, add coverage for gram-negative bacilli AND Candida species in addition to gram-positive coverage. 1

Use empirical antifungal therapy for septic patients with risk factors including total parenteral nutrition, prolonged broad-spectrum antibiotics, hematologic malignancy, transplant recipients, femoral catheterization, or multi-site Candida colonization. 1 Echinocandins (caspofungin, micafungin, or anidulafungin) are preferred as empirical therapy for Candida species. 1

Catheter-Specific Management

Nontunneled Central Venous Catheters

Remove the catheter if blood cultures are positive or if the catheter is exchanged over a guidewire and shows significant colonization (>15 CFU by semiquantitative culture or >10² CFU by quantitative culture). 2, 3

In select patients without evidence of persistent bloodstream infection, if the infecting organism is coagulase-negative staphylococcus and there is no suspicion of local or metastatic complications, the catheter may be retained. 2

After catheter removal, nontunneled catheters may be reinserted after appropriate systemic antimicrobial therapy is begun. 2

Tunneled Catheters and Implantable Devices

Remove tunneled catheters or implantable devices for complicated infections. 2 Complicated infections include tunnel or pocket infections, port abscess, persistent bacteremia, or metastatic complications. 2, 1

For uncomplicated infections, attempt catheter salvage using antibiotic lock therapy for 2 weeks combined with standard systemic therapy for catheter-related bacteremia due to S. aureus, coagulase-negative staphylococci, and gram-negative bacilli. 2

Reinsertion of tunneled devices should be postponed until after appropriate systemic antimicrobial therapy is begun and repeat blood cultures yield negative results. 2 Ideally, insertion should occur after completing the antibiotic course and obtaining negative blood cultures 5-10 days later. 2

Hemodialysis Catheters

Catheter-related coagulase-negative staphylococcal bloodstream infection can be treated without catheter removal, but this may require longer duration of therapy. 2

Use antibiotic lock therapy when the catheter is retained. 2 For hemodialysis patients, the empirical regimen is vancomycin 20 mg/kg loading dose during the last hour of dialysis, then 500 mg during the last 30 minutes of each subsequent session, plus gentamicin 1 mg/kg (max 100 mg) after each dialysis session. 1

Pathogen-Specific Treatment

Staphylococcus aureus

Perform transesophageal echocardiography (TEE) in patients without contraindications to identify complicating endocarditis, as recently reported rates of endocarditis are high. 2, 1

Use antistaphylococcal penicillinase-resistant penicillin (nafcillin or oxacillin) for methicillin-susceptible S. aureus rather than vancomycin, as glycopeptides are inferior to antistaphylococcal penicillins. 2

Treatment duration:

• 14 days for uncomplicated bacteremia with catheter removal and negative TEE 1
• 4-6 weeks for complicated infection or positive TEE 1
• Day 1 of therapy is defined as the first day with negative blood cultures 1

Gram-Negative Bacilli

Treat for 10-14 days with appropriate antimicrobial therapy for nontunneled catheters with catheter removal. 1

Consider catheter removal for Pseudomonas species (other than P. aeruginosa), Burkholderia cepacia, Stenotrophomonas, Agrobacterium, or Acinetobacter baumannii, especially if bacteremia persists or the patient becomes unstable. 1

Candida Species

Remove all tunneled catheters or implantable devices immediately in cases of documented fungemia due to Candida species. 1

Use amphotericin B for hemodynamically unstable patients or those with prolonged fluconazole exposure. 1 Use fluconazole for stable patients without recent fluconazole therapy and susceptible organisms. 1

For septic thrombosis of the great central vein due to Candida species, a prolonged course of amphotericin B therapy is effective; fluconazole can be used if the strain is susceptible. 2

Antibiotic Lock Therapy Concentrations

When using antibiotic lock therapy for catheter salvage:

• Vancomycin 2.5-5.0 mg/mL (5.0 mg/mL more efficacious for biofilm eradication) 1
• Cefazolin 5.0 mg/mL for methicillin-susceptible staphylococci 1
• Gentamicin 1.0 mg/mL for gram-negative organisms 1
• Ceftazidime 0.5 mg/mL for gram-negative organisms 1
• Ciprofloxacin 0.2 mg/mL for gram-negative organisms 1
• 70% ethanol lock for mixed infections 1

Management of Complications

Septic Thrombosis

Remove the involved catheter in all cases. 2

Perform incision and drainage and excision of the infected peripheral vein and any involved tributaries, especially when there is suppuration, persistent bacteremia or fungemia, or metastatic infection. 2

Use heparin for septic thrombosis of the great central veins and arteries, but it is not indicated for routine management of septic thrombosis of peripheral veins. 2

Duration of antimicrobial therapy for septic thrombosis of great central veins should be the same as for endocarditis (4-6 weeks); vein excision is usually not required. 2

Persistent Bloodstream Infection and Endocarditis

For persistent bacteremia or fungemia, remove the device in most instances. 2

Patients with repeatedly positive blood cultures and/or unchanged clinical status for 3 days after catheter removal should be treated presumptively for endovascular infection for 4 weeks of antimicrobial therapy with surgical intervention when indicated. 2

Empirical therapy must include coverage for staphylococci in this situation. 2

Critical Pitfalls to Avoid

Do not use linezolid for empirical therapy in patients suspected but not proven to have bacteremia. 1

Do not use thrombolytic agents in addition to antimicrobial agents in patients with catheter-related bloodstream infection and thrombus formation. 2

Do not routinely culture catheter tips unless catheter-related bloodstream infection is suspected; this should not be a routine practice. 3

Avoid vancomycin for methicillin-susceptible S. aureus bloodstream infections because of the risk of selecting out vancomycin-resistant organisms and inferior outcomes compared to antistaphylococcal penicillins. 2