Catheter associated Blood stream Infections

Definition : It is defined as presence of Bacteremia originating from I.V. Catheter.

Most common cause of Nosocomial Bacteremia.

It is most frequent, lethal and costly complication of Central Venous Catheterization.

• The incidence of CRBSI arising from Central Venous catheters is approximately 10%

• CRBSI has a mortality rate of up to 25% and significantly increases hospital length of stay and overall treatment cost.

• CRBSI can originate from peripheral i.v. and intra-arterial cannulae, but this is extremely rare.

• Pulmonary artery catheters have similar incidence of CRBSI to CVCs; dialysis catheters appear to have a much higher rate.

• Example of Intravascular Devices that can cause CRBSI :

1. Peripheral vascular catheters ( venous/arterial )2. Central venous catheters3. Pulmonary Artery catheter4. Peripherally inserted central catheter.

• Common organisms causing CRBSIs:1. CONS – 31%2. S. Aureus – 20%3. Enterococci – 9%4. Gram Neg. Bacilli ( E.Coli ) – 6%5. Pseudomonas – 5%6. Yeasts – 9%• Recent studies have shown that rates of MRSA,

Ceftazidime resistant P.Aeruginosa, Vancomycin resistant Enterococci causing CRBSI have increased significantly.

• Pathogenesis of CRBSI : 2 primary causes 1. Contamination of fluids being administered.2. Bacterial colonization of devices.a) Extra Luminal : From surrounding skin, Hematogenous

seeding of catheter tip.b) Intra Luminal : Caused by organism adhering to device

followed by creation of Bio-film, a process responsible for persistent infection/ Hematogenous spread.

• In short term devices, Extra Luminal route is more frequent.

• In long term devices ( >10 days ), Intra Luminal route is more common

Diagnosis of CRBSI is based on the following: 1. The presence of a CVC.2. signs of catheter insertion site infection3. clinical symptoms and signs of Bacteremia;4. resolution of the symptoms and signs of

Bacteremia after removal of the suspect CVC;5. positive blood culture; and6. growth of the same organism from the catheter.7. Confirmation that organism is not a contaminant.

• In practice, a presumptive diagnosis of CRBSI is often made on the basis of one or two of above criteria.

• The ‘gold standard’ is the combination of a positive blood culture with the same organism isolated from the catheter.

• However, a major diagnostic problem is that traditional methods of catheter culture necessitate removal of the CVC, whereby the line tip is either rolled on an agar plate or placed in a nutrient broth.

• Although catheter removal in suspected CRBSI may be mandatory when faced with a deteriorating patient, 80% of catheters removed on the basis of fever and/or leukocytosis alone will be sterile.

• This places the patient at risk from the discomfort and mechanical complications of inserting another CVC and increases costs.

• Thus, there has been an impetus to develop in situ methods of microbiological diagnosis.

• Quantitative blood culture. CRBSI is suggested when the number of microbes from a CVC sample of blood is five times that from a simultaneously collected peripheral sample. This is not widely available. (>100 cfu/ml in case of peripheral line)

• Acridine orange staining of blood taken from the CVC. This is not widely available.

• Endoluminal brush sampling. A tiny brush is passed down the catheter lumen and is examined microbiologically by culture. This test has a high sensitivity and specificity but is not widely available. In addition, there are concerns about the generation of a bacteraemia caused by dislodgement of organisms.

• Differential time to positivity. CRBSI is suggested when blood from the CVC demonstrates microbial growth at least 2 h earlier than growth is detected in blood collected simultaneously from a peripheral vein.

• Management : relies on 2 major clinical decisions:1. Appropriate & Timely administration of Systemic

Antimicrobial Treatment (SAT)2. Catheter removal or Catheter Salvage Treatment.

• Guidelines from Infectious disease society of America recommend removal of Catheter in all :

1. All complicated Infections ( thrombophlebitis, Endocarditis, Osteomylitis )

2. All infections caused by ( S.Aureus, Candida, Enterococcus, Gram Neg. Bacilli )

• Catheter may be retained in CONS if systemic antibiotics are given in conjunction with Antibiotic Lock Therapy.

1. CONS – Remove and give SAT for 5-7 days or Retain and give SAT+ALT for 10-14 days.

2. S.Aureus – Remove, SAT for minimum of 14 days. In case of Long term CVC, Remove and SAT for 4-6 weeks

3. Enterococci – Remove, SAT for 10-14 days.4. Gram Negative Bacilli – Remove, SAT for 10-14

days.5. Candida species – Remove, SAT for 14 days after

first negative Blood Culture.6. Complicated Infection ( Endocarditis, Septic

thrombophlebitis, Osteomylitis ) – Remove SAT for 4-6 weeks. For Osteomylitis : 6-8 weeks.

• Antibiotic Lock Therapy : Here 2ml of solution is infused into the lumen of the catheter and remains there for a certain amount of time per day during course of treatment.

• In the lock therapy, Antibiotic concentration ranges 100 to 1000 times the usual systemic concentration. These increased concentration has greater likelihood for killing organism embedded in biofilm.

• It should be used for 10-14 days.

• Prevention : 1. Education and Training all Healthcare personnel

who insert and maintain catheter.2. Using single lumen catheter unless multiple ports

are essential.3. Consider use of an antimicrobial impregnated

catheter for patients at high risk of CRBSI.4. Consider use of peripherally inserted catheters as

an alternative to CVCs.5. Use of Subclavian route unless contraindicated

6. Use optimum insertion technique including sterile gown, gloves and drapes

7. Clean the insertion site with alcoholic chlorhexidine gluconate solution ( or alcoholic povidone iodine ) and allow to dry.

8. Use sterile gauze or transparent dressing over the insertion site.

9. Catheter flush solutions should contain anticoagulant.

10. Replacement strategies : Do not routinely replace CVCs as a strategy to prevent infections.

11. Guidewire exchange is acceptable for malfunctioning catheters if there is no evidence of infection.