Approach to Catheter-related Bloodstream Infections in Patients on Haemodialysis

Nephrology discussionRegistrar: Dr. Coetser

Consultants:Prof. Van Rensburg

Dr. Rossouw

INTRAVASCULAR

INTRACUTANEOUS

INTRALUMINAL AND/OR HUB

TUBING

INFUSATE

Prevention of CRBSI 5 principles strongly recommended by CDC:

Hand washing Full barrier precautions during insertion of central venous

catheters Chlorhexidine for skin disinfection Avoidance of the femoral insertion site Removal of catheters when no longer indicated

If these principles are adhered to, showed a 12% sustainable reduction in incidence of CRBSI in intensive care unitsPronovost, PJ et al. Sustaining reductions in catheter related bloodstream infections in Michigan intensive care units: observational study. BMJ 2010; 340

Unique features in the haemodialysis patient applicable in our setting Usually outpatients Hospitalization only indicated for severe sepsis or metastatic

infection Parenteral antibiotics can be given during dialysis sessions Preference given to antibiotics that can be delivered during

dialysis Peripheral venous access unavailable or should be avoided Catheter removal often requires urgent placement of a new

dialysis catheter Quantitative blood culture and/or determining differential

time to positivity frequently unable to be done

Risk of infection vs. location in dialysis catheters Subclavian catheters have least risk

of infection, but high incidence of

venous stenosis Femoral catheters have highest

risk of infection due to microbial

load and should be avoided if

possible Internal jugular catheters have an

intermediate risk of infection, but

is the most appropriate site for

acute haemodialysis access

Unique aspects in haemodialysis:Obtaining blood cultures Peripheral blood samples should spare veins for potential

fistula creation (A-III) If no sample can be obtained, blood culture can be taken from

bloodlines connected to the catheter during haemodialysis (B-II)

If no sample can be obtained from peripheral site, no other catheter is in situ and no drainage from exit site that can be cultured, accept positive culture from dialysis catheter as evidence of a CRBSI (B-II)

Category, grade Definition

Strength of recommendation

A Good evidence to support a recommendation for or against use

B Moderate evidence to support a recommendation for or against

use

C Poor evidence to support a recommendation

Quality of evidence

I Evidence from more than 1 properly randomized, controlled

trial

II Evidence from more than 1 well-designed clinical trial,

without randomization; from cohort or case-controlled analytic

studies; from multiple time series; or from dramatic results

from uncontrolled experiments

III Evidence from opinions of respected authorities, based on

clinical experience, descriptive studies, or reports of expert

committees

Unique aspects in haemodialysis:Removal of infected catheter Always remove catheter when these organisms are cultured

(A-II) S. aureus Pseudomonas spp Candida spp

If no alternative sites for catheter placement, exchange infected catheter over a guidewire (B-II)

Place longterm catheter again when blood cultures become negative (B-III)

Unique aspects in haemodialysis:Removal of infected catheter For other pathogens (gram-negative bacilli other than

Pseudomonas or coagulase-negative staph) catheter need not be removed immediately. Start empiric antibiotics (B-II)

3 options remain: If symptoms resolve within 2-3 days, exchange infected catheter over

guidewire (B-II) or Leave catheter in place and treat with antibiotic lock for 10-14 days

(B-II) If symptoms persist, or signs of metastatic infection present, remove

line

Unique aspects in haemodialysis:Removal of infected catheter Treating with antibiotics alone and not removing the infected

catheter is not satisfactory: Bloodstream infection returns in majority after therapy is stopped Treatment failure risk is 5x higher

Catheter should be inserted at a new sight or at least be exchanged over a guidewire

Unique aspects in haemodialysis:Empiric antibiotic coverage Include vancomycin and coverage for gram-negative bacilli

(e.g. 3rd generation cephalosporin, carbapenem or beta-lactam/beta-lactamase combination) (A-II)

Aminoglycosides, e.g. gentamycin, can be used, but risk of irreversible ototoxicity

If found to have methicillin-susceptible S.aureus, switch to cefazolin (20mg/kg) after each dialysis session

Unique aspects in haemodialysis:Empiric antibiotic coverage

Unique aspects in haemodialysis:Duration of antibiotic treatment Uncomplicated infection and no evidence of metastatic

infection: Coagulase negative staph

5-7 days if catheter removed (B-III) 10-14 days if catheter retained, in combination with antibiotic lock (B-

III) S. aureus

4-6 weeks Shorter duration (minimum 14 days) can be considered in:- non-diabetics - non-immunosuppressed- catheter removed - no prosthetic intravascular device- no evidence of endocarditis - fever and bacteraemia resolve within

72h on TEE (5-7 days after onset) - no evidence of metastatic infection

Unique aspects in haemodialysis:Duration of antibiotic treatment 4-6 weeks if complicated infection, i.e.:

Persistent bacteraemia or fungaemia (>72h) after infected catheter was removed

If infective endocarditis or suppurative thrombophlebitis present

6-8 weeks for osteomyelitis Surveillance blood culture to be taken 1 week after

completion of antibiotic course. If culture postive, remove catheter and only place new longterm catheter when blood culture becomes negative

Antibiotic lock Definition

A solution of antibiotic and heparin instilled into a catheter lumen. Solution is then left in place for a certain time period.

Mechanism of action Bacteria form a biofilm on the endoluminal side of a long-term

placed catheter Bacteria are sequestered here from systemic levels of antibiotics Antibiotic lock delivers supratherapeutic levels of antibiotics to the

biofilm

Antibiotic lock therapy Indications (B-II):

CRBSI in patients with long-term (>2 weeks) catheters in which salvage is desirable

No signs of exit site or tunnel infection must be present

Success rates: Gram-negative pathogens (87-100%) Staphylococcus epidermidis (40-50%) Staphylococcus aureus (40-55%)

Antibiotic lock therapy:Practical aspects Use in conjunction with systemic antibiotic therapy for 7-14

days (B-II) Dwell times not >48h

Preferably q24h in patients with femoral catheters If undergoing haemodialysis, change lock with every session

Not all antiobiotics are suitable for use in combination with heparin, as precipitation can occur

Antibiotic lock is unlikely to have effect if catheter has been in place for <2 weeks

Antibiotic lock therapy:Practical aspects Do not use antibiotic lock and remove catheter for S.aureus

and candida infections, unless no alternative site available If multiple positive catheter culture results for coagulase-

negative staph or gram-negative bacilli, but negative peripheral cultures, antibiotic lock can be given for 10-14 days without systemic antibiotics (B-III)

Antibiotic lock therapy:Practical aspects

*

* Insufficient data to recommend ethanol lock