CLABSI

Question 1

Catheter-Related Bloodstream Infections (CRBSI)
Definition

Evidence based CC

Answer 1

=>Definition:
A CLABSI is a laboratory-confirmed bloodstream infection (BSI) in a patient who had a central line within the 48 hour period before the development of the BSI, and that is not related to an infection at another site

->There is no minimum period of time that the central line must be in place in order for the BSI to be considered central line-associated, but there must have been one within 48 hours of onset of infection

->Confirmed by quantitative culture of the catheter tip or by isolating the organism from catheter vs peripheral blood.

Question 2

Pathogenesis & Entry Points

LITFL

Answer 2

PATHOGENESIS

=>Mechanisms

• Contamination during insertion
• Contamination of insertion site (post-insertion)
• Contamination of infused substance
• Subsequent contamination due to breaking of sterile connection (multi-flow, 3 way taps)
• Subsequent contamination from systemic infection
• Bacterial migration-
  migration of microbes from catheter-skin interface extralumenally to the catheter-vessel interface (most common situation)
• Migration from hub intra-lumenally

Question 2

Incidence

Answer 2

=>Expressed as CRBSI per 1000 catheter-days.

=>Calculated as
No. of CVC infections x 1000/ No. of CVC days

• Strict adherence to infection-control bundles significantly reduces rates.

Question 3

Risk factors

Answer 3

=>Patient Related
=> Procedure/ CVC related
=> Maintainence related

Question 4

Risk factors

Answer 4

Catheter-related:
* Duration of catheter placement.
* InsertionTechnique
* choice of site
* Ab impregnated- lower risk
* Multiple lumens.

Question 4

Risk factors

Answer 4

=>Patient:
* Immunosuppression, malignancy, burns, renal failure, diabetes, severity of illness.
* Hemodialysis patients → ↑ gram-positive infections.
* Femoral site → ↑ risk (especially gram-negative and Candida).

Question 5

Risk factors

Answer 5

Personnel/environment:
* Overcrowding, staffing deficits, poor isolation capacity.
* TPN infusion.
* Poor line care / breaches in aseptic technique.
* Suboptimal antimicrobial stewardship.

Question 6

Microbiology

Answer 6

Coagulase-negative staphylococci 34.1%>
Enterococci > Candida > Staphylococcus aureus > Klebsiella > Enterobacter > Pseudomonas > E. coli
* Miscellaneous 10.5%

=> Gram-positive infections dominate; gram-negative infections more common with malignancy + femoral site; dialysis lines frequently → Candida risk.

Question 6

Diagnosis:
* Clinical suspicion
* Catheter site assessment
* Microbiological smapling

Answer 6

Diagnosis

->Clinical suspicion
* Suspect CRBSI in any patient with a CVC in situ who develops typical signs of inflammatory illness.
* Must ensure alternative sources of infection are not overlooked.

->Catheter site assessment
* Inspect for redness, induration, pus, discharge at the exit site.
* Soiled dressings → early indicator.
* Inability to aspirate from all catheter lumens → may indicate lumen thrombosis(thrombus- nidus for infection).

Question 6

Microbiological sampling
=>Paired samples
=>Differential time positivity
=>Catheter tip culture
=>Biomarkers

Answer 6

=>Paired samples
(peripheral + catheter lumen) are mandatory.
* At least 20 mL blood collected.
* ≥15 CFU from catheter tip (semiquantitative)
OR
>10² CFU (quantitative) → significant.
* Multilumen catheters: sample all lumens.

=>Differential Time to Positivity (DTTP)
* Growth of the same organism from catheter-drawn blood ≥120 minutes earlier than peripheral blood supports CRBSI.
* Helps reduce unnecessary catheter removal.

=>Catheter tip culture
* When catheter removed: ≥15 CFU with same organism as peripheral blood → diagnostic.

Biomarkers
* Emerging options (e.g., presepsin, FISH probes), particularly in neutropenic or pediatric patients.

FISH- flourescence in situ hybridization

Question 7

Treatment

Answer 7

General principles of Mx of sepsis apply.
* Two priorities:
1. Obtain cultures first (peripheral + CVC).
2. Start broad-spectrum antibiotics based on local microbiology->de escalate once sensitivities known.

• Supportive care and source control important.

->Most short-term CVC infections require immediate removal.

->For long-term catheters: remove only if
* Severe sepsis
* Hemodynamic instability
* Endocarditis
* Metastatic infection
* Tunnel infection
* Fungal infection

Question 8

If device cannot be removed

Answer 8

=>Consider antibiotic lock therapy (instillation of high-concentration antibiotics into each lumen).
* Must be done with ID specialist consultation.

=>Exchange over a guide wire is an option only in exceptional circumstances where new vascular access deemed risky or impossible- ID team needs to be involved.

Question 9

Antibiotic duration

( based on organism and absence of metastatic complications)

Answer 9

=>Coagulase-negative Staphylococci
5–7 days

=>Enterococci
7–14 days

=>Gram-negative bacilli
7–14 days

=>S. aureus
14 days if no metastatic complications; 4–6 weeks if endocarditis, osteomyelitis, discitis, epidural abscess

=>Candida
14 days from last negative culture; remove catheter

Question 9

Prevention

Answer 9

=>Overall principle
* PROTOCOLISED PROGRAME of
* METICULOUS INFECTION CONTROL MEASURES, supported by
* EDUCATION AND SURVEILLANCE can reliably reduce CRBSI rates institution-wide.

Question 10

Key Preventive Measures

Answer 10

1). Personnel
* Experienced operator/trainee under close supervision.
* Operator must don cap, mask, sterile gown, sterile drape after hand hygiene.
* All personnel present must wear cap and face mask.

⸻

2). Site Selection
* Prefer subclavian site over internal jugular/femoral vein.

⸻

3). Device
* Choose least number of lumens needed.
* Consider antimicrobial-impregnated catheters (chlorhexidine/silver sulfadiazine OR minocycline/rifampicin) when infection control compliance is suboptimal.
* Consider peripheral central catheters if feasible.

Question 10

Arterial Lines & PICC Lines

Answer 10

=>Arterial lines
* Often overlooked as CRBSI sources.
* Incidence ~0.7 infections/1000 catheter-days, especially ↑ with femoral arterial placement.
* Require same aseptic standards as CVCs.

=>PICC lines
* Increasingly used in ICU and outpatient settings.
* Low outpatient infection rates; limited evidence on ICU rates.
* May replace conventional CVCs in many institutions.

Question 10

Key Preventive Measures cont..

Answer 10

4). Technique during insertion
* >0.5% chlorhexidine for skin antisepsis (allow to dry).
* Use whole-body sterile drape.
* If sterility compromised, remove and replace catheter.
* Do not use prophylactic systemic antibiotics at insertion.

⸻

5). Post-insertion care
* Perform meticulous hand hygiene before any procedure.
* Inspect site daily.
* If oozing: gauze dressing + change every 2 days.
* If dry: semipermeable dressing + change every 7 days (or earlier if soiled).
* Do not change catheters routinely; only if clinically indicated

Question 10

Evidence

Answer 10

=>Skin prep with Chlorhexidine-containing solutions(>0.5%) ↓ CRBSIs by 36% vs povidone–iodine.

=> Antibiotic impregnated vs Non impregnated:
* Minocycline–rifampicin catheters outperform silver–sulfadiazine catheters, especially in ICU and oncology/dialysis patients.

• Overall, ⬇️ colonisation of site and CRBSI with Ab impregnated catheters.
• No clear mortality benefit / reduction in all cause sepsis in Impregnated vs nonimpregnated.
• Impregnated dressings → limited evidence; not routine.
• Antibiotic lock therapy lacks evidence for routine prophylactic use.