How to treat a patient with fungal catheter-related bloodstream infection (CRBSI) with different cultures at two sites?

Management of Fungal CRBSI with Different Cultures at Two Sites

Remove the catheter immediately and treat with systemic antifungal therapy targeting the most resistant organism identified, as fungal CRBSI cannot be successfully managed with catheter retention. 1

Immediate Catheter Management

Both short-term and long-term catheters must be removed immediately when fungal CRBSI is diagnosed. 1 The IDSA guidelines explicitly state that catheters should be removed for infections due to fungi, regardless of catheter type. 1 This is a non-negotiable recommendation with A-II level evidence. 1

• Do not attempt catheter salvage for fungal infections, even in patients with limited vascular access who require long-term intravascular access for survival (e.g., hemodialysis patients, short-gut syndrome). 1 Fungi are explicitly excluded from catheter salvage protocols due to biofilm formation and unacceptably high failure rates. 2, 3

• If a temporary catheter is needed (e.g., for hemodialysis), insert it at a different anatomical site after catheter removal. 4

Empirical Antifungal Selection

When different fungal species are cultured from two sites, initiate an echinocandin (caspofungin, micafungin, or anidulafungin) as first-line empirical therapy while awaiting final speciation and susceptibility results. 1

• Use an echinocandin rather than fluconazole if the patient has had azole exposure in the previous 3 months, or if there is any risk of Candida krusei or Candida glabrata infection. 1

• Fluconazole can only be considered if: (1) no azole exposure in the past 3 months, AND (2) the healthcare setting has very low risk of C. krusei or C. glabrata, AND (3) both organisms are confirmed susceptible. 1

• Caspofungin dosing: 70 mg loading dose on Day 1, followed by 50 mg once daily. 5

Targeted Therapy Based on Speciation

Once both organisms are identified and susceptibilities are known:

• Treat to cover the most resistant organism or the one with the highest virulence potential (e.g., if one site grows fluconazole-susceptible Candida albicans and another grows C. glabrata, continue echinocandin therapy). 1

• If both organisms are fluconazole-susceptible and the patient is clinically stable, de-escalation to fluconazole is acceptable after initial echinocandin therapy and documented blood culture clearance. 1

Treatment Duration

Day 1 of treatment is defined as the first day negative blood cultures are obtained. 1

• Minimum 14 days of antifungal therapy after the last positive culture for uncomplicated fungal CRBSI. 1, 6

• Extend to 4-6 weeks if: (1) fungemia persists >72 hours after catheter removal despite appropriate antifungals, OR (2) endocarditis is diagnosed, OR (3) suppurative thrombophlebitis is present, OR (4) metastatic infection occurs. 1, 6

• Neutropenic patients who remain persistently neutropenic may require longer therapy pending resolution of neutropenia. 5

Monitoring and Follow-Up

Obtain repeat blood cultures 72 hours after initiating appropriate antifungal therapy. 1, 6

• If blood cultures remain positive at 72 hours, remove any retained catheter immediately (though this should not occur with fungal CRBSI as the catheter should already be removed). 1, 6

• Perform transesophageal echocardiography if: (1) cultures remain positive at 72 hours, OR (2) new cardiac murmurs develop, OR (3) embolic phenomena occur, OR (4) persistent fever despite appropriate therapy. 6

• Evaluate for metastatic complications including endophthalmitis (which occurs frequently with Candida bacteremia and can cause vision loss), infective endocarditis, arthritis, embolic pneumonia, and suppurative thrombophlebitis at the catheter insertion site. 2

Critical Pitfalls to Avoid

• Never attempt catheter retention for fungal CRBSI, even with antimicrobial lock therapy. 1 This is fundamentally different from bacterial CRBSI management where salvage may be attempted for certain organisms. 1

• Do not treat based on culture from only one site - ensure you have adequate sampling from both peripheral vein and catheter hub (or two peripheral sites) to confirm true CRBSI versus contamination. 1

• Do not use fluconazole empirically if the patient has had recent azole exposure or if local epidemiology suggests risk of azole-resistant species. 1

• Do not stop antifungals prematurely - the minimum 14-day duration starts from the first negative blood culture, not from catheter removal or symptom resolution. 1, 5