3.3 Bloodstream Infections & CLABSI Prevention

Clinical impact and why definitions matter

Catheter-related bloodstream infections cause morbidity, prolonged length of stay, excess cost, and mortality risk. Infusion nurses are accountable for prevention at insertion and every subsequent access. On the CRNI exam, precise language matters: CLABSI and CRBSI are related but not identical concepts.

CLABSI vs CRBSI

CLABSI (central line–associated bloodstream infection) is primarily a surveillance definition used by infection prevention programs (aligned with CDC/NHSN-style criteria). In simplified terms, a CLABSI is a laboratory-confirmed bloodstream infection in a patient with a central line (or recently in place per definition rules) without another identifiable infection source meeting exclusion criteria. Surveillance definitions support rate tracking and benchmarking; they may include some infections that are not definitively proven to originate from the catheter.

CRBSI (catheter-related bloodstream infection) is a clinical diagnosis that the catheter is the source of bacteremia/fungemia. It typically requires stronger catheter-specific evidence, such as:

• Same organism from peripheral blood and catheter lumen/tip with quantitative or differential time-to-positivity criteria when used, and/or
• Clinical picture plus microbiologic data supporting the device as source after alternative sources are considered

Exam pearl: Do not use the terms interchangeably in answers. CLABSI = surveillance association with a central line; CRBSI = clinical attribution to the catheter.

Peripheral IV–associated bloodstream infection can occur but is less often the focus of “CLABSI” metrics; still, peripheral sites can seed infection and must be maintained with aseptic access and timely removal for complications.

Pathogenesis pathways

Organisms reach the bloodstream via:

1. Extraluminal route — skin flora migrate along the external catheter surface from the insertion site (especially early after insertion).
2. Intraluminal route — contamination of hubs/needleless connectors, leading to lumen colonization and biofilm (often with longer dwell and frequent access).
3. Contaminated infusate — intrinsic manufacturing contamination (rare) or extrinsic contamination during preparation/administration.
4. Hematogenous seeding — organisms from a distant infection adhere to the catheter.

Understanding the route drives prevention: insertion barriers and site care target extraluminal infection; hub discipline targets intraluminal infection; sterile compounding targets infusate contamination.

Common pathogens

Know the frequent players and clinical hints:

• Coagulase-negative staphylococci (CoNS): common contaminants and true pathogens of indwelling devices; interpret cultures carefully with clinical correlation.
• Staphylococcus aureus (MSSA/MRSA): high virulence; metastatic foci (endocarditis, osteomyelitis) are a concern—prompt source control matters.
• Candida spp.: associated with TPN, broad-spectrum antibiotics, immunosuppression; candidemia generally warrants catheter removal in most clinical situations per infectious disease principles.
• Gram-negative organisms: Klebsiella, Enterobacter, Pseudomonas, E. coli, etc.; may suggest healthcare environment, GI translocation, or contaminated water sources for some species.
• Enterococci: device and healthcare-associated infections, including VRE considerations for isolation.

Biofilm protects organisms from host defenses and antibiotics, which is why device removal is often required for cure when the catheter is the source.

CLABSI prevention bundles

A bundle is a small set of evidence-based practices implemented together. Typical central line insertion and maintenance elements include:

Insertion bundle (examples):

• Hand hygiene before the procedure
• Maximal sterile barrier precautions (cap, mask, sterile gown, sterile gloves, full-body drape)
• Skin antisepsis with >0.5% CHG in alcohol (unless contraindicated) with complete dry time
• Optimal site selection (avoid higher-risk sites when alternatives exist; follow population-specific guidance)
• Sterile insertion technique by a trained operator; ultrasound with sterile cover/gel when used

Maintenance bundle (examples):

• Hand hygiene before every line access
• Hub/needleless connector disinfection (scrub the hub per product and policy—often alcoholic antiseptic with specified scrub and dry time; some systems use disinfection caps)
• Aseptic administration set management and timely tubing changes per protocol
• Dressing integrity: sterile transparent or gauze dressings; CHG-impregnated dressings where indicated
• Daily review of line necessity with prompt removal when not needed
• CHG bathing for selected ICU or high-risk populations per facility protocol
• Minimize blood draws and entries; batch compatible medications when safe
• Staff competency and standardized kits/checklists

Exam trap: Knowing CHG skin prep but forgetting daily necessity review—or scrubbing the hub inadequately between multiple medication pushes.

Culturing principles

When bloodstream infection is suspected in a patient with a VAD:

• Obtain blood cultures before antibiotics when possible without delaying critical care.
• Paired cultures—peripheral venipuncture plus cultures from the catheter lumen(s)—are often used when CRBSI is in the differential and the line will remain temporarily. Differential time to positivity (catheter bottle positive sufficiently earlier than peripheral) can support catheter source when validated methods are used.
• Draw adequate volumes; poor volume reduces sensitivity.
• Avoid culturing through a visibly contaminated setup; disinfect hubs before sampling from lines.
• Catheter tip culture may be performed when a line is removed for suspected CRBSI, but tip culture alone without blood culture correlation has limitations; follow local ID protocol.
• Do not treat every positive CoNS as true bacteremia without clinical evaluation—contamination vs true infection is a classic interpretation challenge.

Document site appearance, dressing status, number of lumens, TPN use, and recent accesses to support the clinical picture.

When to remove the catheter

Removal decisions are clinical and often multidisciplinary, but CRNI-level principles include:

• Remove peripheral IVs with signs of purulent phlebitis, progressive infection, or when no longer needed.
• For suspected CRBSI, remove short-term non-tunneled catheters that are likely sources, especially with S. aureus, Pseudomonas, or Candida, severe sepsis, endocarditis, or persistent bacteremia—follow current ID guidance and do not rely on “flushing the infection out.”
• Some long-term devices (tunneled catheters, ports) may occasionally be salvaged in select CoNS infections without complications under infectious disease direction—but salvage is never automatic and requires that the device remain essential.
• Always reassess: if the device is not needed, removal is both treatment and prevention.
• After removal, culture as indicated, start appropriate antibiotics, and place a new device at a new site only if ongoing access is required—do not rewire through a frankly infected tract as a casual default.

Exam trap: Choosing to irrigate an infected central line vigorously as primary treatment, or leaving an unnecessary multi-lumen CVC in place “for blood draws” during documented CLABSI workup without necessity.

Recognition and response

Clinical clues: fever/chills (sometimes with infusion), hemodynamic instability, new confusion, exit-site erythema/purulence, tunnel infection signs, or port pocket infection. Not all CRBSI shows local site findings—systemic signs may dominate, especially with intraluminal infection.

Response sequence: stabilize ABCs → notify provider → obtain cultures per protocol → do not delay sepsis care → evaluate catheter necessity and removal criteria → implement isolation if pathogen requires it → document and report per infection prevention policy.

Linking prevention to hours of safe therapy

Every unnecessary lumen and every undisinfected access is a probabilistic risk. Checklists at insertion, observation of sterile field breaks, empowerment to stop the line, and standardized hub practice are how units drive CLABSI rates toward zero. For the exam, if an option reflects bundle fidelity + early removal of unneeded CVADs, it is usually stronger than an option that adds gadgets without basic asepsis.

Master CLABSI vs CRBSI, pathogens, bundles, culturing, and removal triggers—and you cover the bloodstream-infection heart of Domain 1B.