Fellow's quick read · Infectious Diseases
Intravascular catheter-related bloodstream infection (CRBSI)
IDSA 2009 (Mermel et al) · reviewed 2026-08-04
Personal study digest for a new ID fellow. Recommendations below are from the IDSA 2009 CRBSI guideline1 (letters in parentheses are its evidence grades). The amber "What's changed since 2009" box is reviewer synthesis of newer evidence, each claim cited — not guideline text. Not a substitute for the full guideline.
In one line
Draw paired blood cultures (catheter + peripheral) before antibiotics, then answer two questions: is the line the source, and does this bug force me to pull it? Remove the catheter for S. aureus, P. aeruginosa, Candida, mycobacteria, and for sepsis / suppurative thrombophlebitis / endocarditis / bacteremia persisting >72 h — salvage is only reasonable for a hard-to-replace long-term line infected by a low-virulence organism (usually coagulase-negative staph), and only with an antibiotic lock plus systemic therapy.
When to suspect & how to confirm it
- Suspect it when a catheterized patient has fever/sepsis with no other source, or blood cultures grow S. aureus, coagulase-negative staph, or Candida. Fever is sensitive but non-specific; inflammation/pus at the exit site is specific but insensitive.1
- Definitive diagnosis (rec 17, A-I/A-II): the same organism from ≥1 percutaneous blood culture AND the catheter tip; or paired blood cultures (catheter hub + peripheral vein) meeting quantitative or DTP criteria — no catheter removal needed for the paired-culture route.
- DTP (differential time to positivity): catheter-drawn culture flags positive ≥2 h before the peripheral one (A-II).
- Quantitative: catheter colony count ≥3-fold (3:1) higher than the peripheral draw (A-II).
- Catheter tip = colonized at >15 CFU (semiquantitative roll-plate) or >10² CFU (sonication) — colonization alone is not CRBSI.
- A single positive coagulase-negative staph culture is usually contamination — repeat paired cultures before treating or pulling the line (rec 38, A-II).
Workup the fellow drives
- Draw cultures before the first antibiotic dose; same blood volume per bottle; label each bottle by site (catheter vs peripheral) so the lab can compute DTP (rec 11, 15, 20).
- Skin/hub prep with alcohol, tincture of iodine, or alcoholic chlorhexidine (>0.5%) — not povidone-iodine — to cut contamination (rec 13-14, A-I).
- Do not culture catheter tips routinely — only when a line is pulled for suspected CRBSI (rec 1). Culture the tip, not the subcutaneous segment; for a pulmonary-artery catheter culture the introducer (rec 3, 8).
- If no peripheral vein is accessible, draw ≥2 samples through different lumens (rec 16).
Empiric therapy — cover the likely bug, then de-escalate
| Situation | Empiric drug | Grade / note |
|---|---|---|
| Gram-positive cover (most patients) | Vancomycin where MRSA is prevalent | A-II · use daptomycin if local MRSA vancomycin MIC >2 µg/mL (rec 23) |
| Suspected but unproven CRBSI | Do NOT use linezolid empirically | A-I · higher mortality in non-bacteremic patients (rec 24) |
| Gram-negative cover | By local antibiogram + severity (4th-gen cephalosporin, carbapenem, or β-lactam/β-lactamase inhibitor ± aminoglycoside) | A-II (rec 25) |
| Neutropenic / severe sepsis / known MDR-GNR colonization | Two anti-GNR agents of different classes, then de-escalate | A-II · covers Pseudomonas (rec 26) |
| Femoral line + critically ill | Add gram-negative and Candida coverage | A-II (rec 27) |
| Suspected catheter-related candidemia1 | Echinocandin (fluconazole only if no azole in 3 mo & low C. glabrata/krusei risk) | A-II · risk factors: TPN, broad-spectrum abx, heme malignancy, transplant, femoral line, multi-site Candida (rec 28-29) |
The core decision: pull the line or try to salvage?
| Catheter | Remove it for… |
|---|---|
| Short-term (in situ <14 d) | S. aureus, gram-negative bacilli, enterococci, Candida/fungi, mycobacteria — i.e. essentially everything except low-virulence CoNS (rec 32, A-II) |
| Long-term (tunneled / port) | S. aureus, P. aeruginosa, fungi, mycobacteria — or severe sepsis, suppurative thrombophlebitis, endocarditis, or bacteremia continuing >72 h on active therapy (rec 32, A-II) |
| Any — tunnel infection or port abscess | Always remove + 7-10 d antibiotics (± I&D) even without bacteremia (rec 44, A-II) |
- Salvage (keep the line) is reasonable only for an uncomplicated long-term-line infection by a low-virulence bug (CoNS, and non-aeruginosa GNR / enterococci case-by-case) when access is precious — always with systemic therapy + antibiotic lock (rec 35).
- If salvage is attempted, repeat cultures at 72 h; still positive → pull the line (rec 33).
Pathogen-specific therapy & duration
Duration day 1 = the first day blood cultures turn negative (rec 22).
| Organism | Line + duration | Drug notes |
|---|---|---|
| Coagulase-negative staph | 5-7 d if removed; 10-14 d + lock if retained (rec 75) | May even observe off antibiotics if no intravascular/orthopedic hardware, line out, follow-up cultures negative (rec 76) |
| S. aureus | Remove line + 4-6 wk; shorten to ≥14 d only if every low-risk criterion is met (rec 78-80) | TEE before short course, done 5-7 d after onset; TTE can't rule out IE. Treat S. lugdunensis like S. aureus (rec 77, 81, 87) |
| Enterococcus | 7-14 d (rec 93) | Ampicillin if susceptible; vancomycin if amp-R; VRE → daptomycin or linezolid (rec 91, 97) |
| Gram-negative bacilli | 7-14 d (rec 100) | Double-cover MDR-GNR empirically, de-escalate to one agent on susceptibilities |
| Candida | Remove line (A-II); treat 14 d after first negative culture (rec 101-103) | Antifungal for all candidemia even if it clears after line removal; echinocandin (or fluconazole in low-risk) |
| Complications | 4-6 wk: persistent BSI/fungemia >72 h after removal, endocarditis, suppurative thrombophlebitis · 6-8 wk adult osteomyelitis (rec 31) | Suppurative thrombophlebitis: minimum 3-4 wk; surgery only if superficial pus or failing therapy (rec 108, 110) |
Antibiotic lock therapy — the salvage adjunct
- Indication: long-term line, catheter salvage the goal, no exit-site/tunnel infection (rec 68).
- Never alone — always with systemic antibiotics, both for 7-14 days (rec 69).
- Do NOT attempt salvage/lock for S. aureus or Candida — remove the line (rec 71, A-II). It targets intraluminal biofilm, which needs ~100-1000× the planktonic MIC (e.g. vancomycin lock 5 mg/mL, ≥1000× MIC); dwell ≤48 h (rec 70, 73).
- Insufficient data to recommend an ethanol lock for treatment (rec 74). Thrombolytics (urokinase) are not adjunctive therapy (rec 37).
Two special situations a fellow meets fast
- Hemodialysis catheter: remove for S. aureus, Pseudomonas, or Candida (rec 57). If MSSA, switch empiric vancomycin to cefazolin, dosed 20 mg/kg after each dialysis session (rec 62-63). For less-virulent bugs with symptoms resolving in 2-3 d, guidewire exchange or a post-dialysis lock (10-14 d) can save access (rec 59-60). VRE → daptomycin 6 mg/kg after HD or linezolid (rec 65).
- ICU fever, line looks fine: culture the line + peripherally and watch rather than reflexively pulling — most suspected lines are sterile (rec 41). If you must exchange and the removed tip grows, replace that new catheter at a fresh site (rec 43).
What's changed since 2009
Reviewer synthesis of newer evidence — not the guideline. Each claim cited.
- The 2009 document is still the operative IDSA management guideline — no newer version exists. The SHEA/IDSA/APIC/AHA/Joint Commission 2022 Compendium updated CLABSI prevention (chlorhexidine, CHG bathing, antimicrobial catheters), not treatment Infect Control Hosp Epidemiol 2022; PMID 35437133.
- Finish complicated SAB without a line — dalbavancin. When the infected line is out and blood is clear, two IV doses (1500 mg days 1 & 8) can complete therapy with no OPAT catheter. DOTS was not superior by DOOR (47.7%) but non-inferior on clinical efficacy; it excluded CNS infection, retained prosthetic material, left-sided endocarditis, and severe immunocompromise JAMA 2025;334(10):866-77; PMID 40802264.
- Vancomycin is now AUC-dosed. Target AUC/MIC 400-600, not troughs — the 2009 empiric-vancomycin rec predates the 2020 revised consensus Am J Health Syst Pharm 2020;77(11):835-64; PMID 32191793.
- New MRSA-active option: ceftobiprole — first cephalosporin FDA-approved (3 Apr 2024) for S. aureus bacteremia incl. right-sided endocarditis; ERADICATE was non-inferior to daptomycin (69.8% vs 68.7% at d70) N Engl J Med 2023;389(15):1390-1401; PMID 37754204.
- Faster bug ID. MALDI-TOF, multiplex molecular blood-culture panels, and T2 magnetic resonance now identify the organism and key resistance markers hours-to-a-day faster than the 2009 text's "16S PCR, not routine," speeding appropriate therapy and de-escalation (general practice shift).
- Candidemia — still pull the line, still echinocandin-first (confirmed by IDSA 2016 candidiasis). Newer option: once-weekly rezafungin, non-inferior to caspofungin in ReSTORE Lancet 2023;401(10370):49-59; PMID 36442484.
- Still solid: paired-culture / DTP≥2 h / quantitative diagnosis; remove the line for S. aureus / Pseudomonas / Candida; echinocandin-first empiric candidemia; no empiric linezolid; systemic-plus-lock for CoNS long-line salvage.
- Open / verify locally: ethanol locks are still not recommended for treatment; taurolidine catheter locks are FDA-cleared for prevention in high-risk patients (e.g. home parenteral nutrition), a distinct indication — confirm formulary status before use.
Anki cards minted this run
- Quantitative / tip diagnosis of CRBSI — catheter colony count ≥3-fold higher than the peripheral draw (the DTP ≥2 h threshold is already in the deck).
- Which pathogens force line removal — short-term vs long-term lists (the salvage-vs-pull decision).
- CoNS CRBSI duration — 5-7 d if removed vs 10-14 d + lock if retained; observe-only option.
- Antibiotic lock rules — never alone (with systemic ×7-14 d); never salvage S. aureus/Candida.
Held under the 4-card cap (already high-yield but deferred): HD-catheter MSSA → cefazolin 20 mg/kg after dialysis; S. aureus ≥14-day short-course criteria (SAB duration is already carded from prior runs).
Sources
- 1. Mermel LA, Allon M, Bouza E, et al. Clinical practice guidelines for the diagnosis and management of intravascular catheter-related infection: 2009 update by the IDSA. Clin Infect Dis 2009;49(1):1-45. doi:10.1086/599376.
- 2. Turner NA, Hamasaki T, Doernberg SB, et al. Dalbavancin for treatment of Staphylococcus aureus bacteremia (DOTS): a randomized clinical trial. JAMA 2025;334(10):866-877. PMID 40802264; doi:10.1001/jama.2025.12543.
- 3. Rybak MJ, Le J, Lodise TP, et al. Therapeutic monitoring of vancomycin for serious MRSA infections: revised ASHP/IDSA/PIDS/SIDP consensus guideline. Am J Health Syst Pharm 2020;77(11):835-864. PMID 32191793; doi:10.1093/ajhp/zxaa036.
- 4. Holland TL, Cosgrove SE, et al. Ceftobiprole for treatment of complicated Staphylococcus aureus bacteremia (ERADICATE). N Engl J Med 2023;389(15):1390-1401. PMID 37754204; doi:10.1056/NEJMoa2300220.
- 5. Thompson GR, Soriano A, et al. Rezafungin versus caspofungin for candidaemia and invasive candidiasis (ReSTORE). Lancet 2023;401(10370):49-59. PMID 36442484; doi:10.1016/S0140-6736(22)02324-8.
- 6. Buetti N, Marschall J, Drees M, et al. Strategies to prevent central line-associated bloodstream infections in acute-care hospitals: 2022 update. Infect Control Hosp Epidemiol 2022;43(5):553-569. PMID 35437133; doi:10.1017/ice.2022.87.
Ceftobiprole FDA indication/date confirmed via FDA/Basilea announcement (Zevtera, 3 Apr 2024).