What is the best treatment approach for an adult patient with chronic kidney disease (CKD) on dialysis, presenting with a catheter-related bloodstream infection (CRBSI) due to Staphylococcus hominis and Salmonella, and a respiratory infection with ESBL (Extended-Spectrum Beta-Lactamase) Klebsiella pneumoniae and Pseudomonas aeruginosa?

Management of Polymicrobial Catheter-Related Bloodstream Infection in a Hemodialysis Patient

Remove the dialysis catheter immediately and initiate empirical vancomycin plus a carbapenem (meropenem preferred) or cefepime to cover the polymicrobial bloodstream infection (Staphylococcus hominis and Salmonella) and respiratory pathogens (ESBL Klebsiella pneumoniae and Pseudomonas aeruginosa), with treatment duration of 10-14 days for uncomplicated infection or 4-6 weeks if bacteremia persists beyond 72 hours. 1, 2, 3

Immediate Catheter Management

Catheter removal is mandatory in this case due to the presence of Salmonella (a gram-negative bacillus) in the bloodstream, which has only a 20% success rate with catheter salvage attempts and a 5-fold higher failure rate when antibiotics are used alone without catheter removal. 1, 3

• Remove the infected catheter and insert a new temporary (non-tunneled) catheter at a different anatomical site. 1, 2
• If absolutely no alternative sites are available, exchange the catheter over a guidewire only after the patient becomes asymptomatic (2-3 days of antibiotics) and blood cultures are negative. 1, 3
• A new long-term hemodialysis catheter can be placed once blood cultures show negative results. 1

Empirical Antibiotic Therapy

Start vancomycin PLUS broad gram-negative coverage immediately while awaiting final susceptibility results. 1, 3, 4

For the Bloodstream Infection (S. hominis + Salmonella):

• Vancomycin: Loading dose of 20 mg/kg (actual body weight) during the last hour of dialysis, then 500 mg during the last 30 minutes of each subsequent dialysis session. 1, 4
• Gram-negative coverage: Use meropenem (preferred for ESBL organisms) OR cefepime (covers Pseudomonas and most Enterobacteriaceae). 1, 2, 3
• Avoid aminoglycosides (gentamicin, tobramycin) due to substantial risk of irreversible ototoxicity in dialysis patients. 1, 2, 3, 4

For the Respiratory Infection (ESBL Klebsiella + Pseudomonas):

• Meropenem is the optimal choice as it covers ESBL Klebsiella pneumoniae, Pseudomonas aeruginosa, AND Salmonella simultaneously, avoiding polypharmacy. 2, 3
• Alternative: Cefepime covers Pseudomonas and non-ESBL organisms but may have reduced activity against ESBL producers—verify local susceptibilities. 3
• Ceftazidime can be used specifically for Pseudomonas but lacks ESBL coverage. 2

Duration of Treatment

The duration depends on clinical response and follow-up blood cultures obtained 72 hours after starting therapy. 1, 2, 3

• Uncomplicated infection (symptoms resolve within 2-3 days, negative blood cultures at 72 hours, no metastatic infection): 10-14 days after catheter removal. 1, 2, 3, 4
• Complicated infection (persistent bacteremia at 72 hours, septic thrombophlebitis, endocarditis, or metastatic infection): 4-6 weeks of therapy. 1, 2, 3, 4
• For osteomyelitis: 6-8 weeks. 4

Monitoring and Follow-Up

Obtain follow-up blood cultures 72 hours after initiating therapy to document clearance of bacteremia. 1, 2, 3

• If cultures remain positive at 72 hours, extend therapy to 4-6 weeks and evaluate for metastatic complications (endocarditis, suppurative thrombophlebitis, epidural abscess, osteomyelitis). 1, 2, 3, 4
• Monitor clinical response: fever, chills, and hemodynamic instability should improve within 2-3 days. 3, 4
• If the catheter was retained (not applicable here due to Salmonella), obtain surveillance blood cultures 1 week after completing antibiotics. 4

Evaluation for Metastatic Infection

Assess for complications that would mandate prolonged therapy: 1, 4

• Suppurative thrombophlebitis
• Endocarditis (echocardiography if bacteremia persists or new murmur develops)
• Osteomyelitis or vertebral discitis
• Epidural abscess (especially with persistent back pain)
• Septic arthritis

Hospitalization Criteria

This patient requires hospitalization given the polymicrobial nature of infection, presence of Salmonella bacteremia, and respiratory co-infection with multidrug-resistant organisms. 2, 3

• Hospitalization is indicated for severe sepsis, hemodynamic instability, or metastatic infection. 2, 3, 4

Critical Pitfalls to Avoid

• Do NOT attempt catheter salvage with Salmonella bacteremia—gram-negative bacilli (especially Salmonella and Pseudomonas) have extremely high failure rates with catheter retention. 1
• Do NOT use aminoglycosides in dialysis patients due to irreversible ototoxicity risk. 1, 2, 3, 4
• Do NOT use antibiotics alone without catheter removal—this guarantees treatment failure with a 5-fold higher failure rate. 2, 3
• Do NOT delay catheter removal beyond 72 hours if bacteremia persists—this increases mortality risk. 1

Addressing the Respiratory Component

While the primary focus is the life-threatening bloodstream infection, the respiratory infection with ESBL Klebsiella and Pseudomonas will be simultaneously treated by the meropenem regimen chosen for the bacteremia. 2, 3

• Ensure adequate source control for any pulmonary process (drainage of empyema if present).
• Adjust antibiotic duration based on clinical and radiographic response of pneumonia (typically 7-14 days for healthcare-associated pneumonia).

Antibiotic Lock Therapy

Antibiotic lock therapy is NOT applicable in this case because the catheter must be removed due to Salmonella bacteremia. 1

• Antibiotic lock therapy can only be considered for coagulase-negative staphylococci (like S. hominis alone) in clinically stable patients without gram-negative co-infection, but the presence of Salmonella makes catheter removal mandatory. 1, 4