Catheter-related blood stream infections

Objectives

1. Catheter-related blood stream infections - Present scenario

2. Methods of diagnosing CRBSI

3. Importance of Differential Time to Positivity method by

automated system

4. Interpret DTP result to diagnose CRBSI

XIII National Workshop on Diagnostic Methods in Clinical Microbiology, JIPMERApr 21, 2023

Catheter-related blood stream infections(CRBSI)

• Bacteremia/ fungemia in a patient with an intravascular

catheter, associated with clinical manifestations of infections

(i.e., fever, chills, and/or hypotension), and no apparent source

for the BSI except the catheter

• Local signs of inflammation – absent in 70% of cases of CRBSI

XIII National Workshop on Diagnostic Methods in Clinical Microbiology, JIPMERApr 21, 2023

Diagnosis

XIII National Workshop on Diagnostic Methods in Clinical Microbiology, JIPMER

Apr 21, 2023

XIII National Workshop on Diagnostic Methods in Clinical Microbiology, JIPMER

(for bacteria)

≥25 CFU/ml(for fungal)

Apr 21, 2023

XIII National Workshop on Diagnostic Methods in Clinical Microbiology, JIPMER

(Maki method)

(Endoluminal flush culture)

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Procedure – Differential time to positivity

XIII National Workshop on Diagnostic Methods in Clinical Microbiology, JIPMERApr 21, 2023

Requirements:

• Automated blood culture system- BACTEC 9120

• Bactec blood culture bottles (Paediatric and/or adult – Aerobic)

XIII National Workshop on Diagnostic Methods in Clinical Microbiology, JIPMER

Apr 21, 2023

Procedure

XIII National Workshop on Diagnostic Methods in Clinical Microbiology, JIPMERApr 21, 2023

XIII National Workshop on Diagnostic Methods in Clinical Microbiology, JIPMER

Collection timePositive signal

Entry in BACTECArrival at Lab Identification and AST

report

Transport time Time to positivity(TTP)

Time to reporting

• TTP of catheter sample(TTPC)• TTP of peripheral sample(TTPP)

Apr 21, 2023

XIII National Workshop on Diagnostic Methods in Clinical Microbiology, JIPMER

Peripheral Central

CRBSI

Negative

≥2 hours

Same organism

Positive Positive Negative

Different organisms

Calculate DTP(TTPP-TTPC)

No Yes

?????

Interpretation

Excluded DTP cannot be measured

PossibleContamination

Local colonization

Apr 21, 2023

THANK YOU

Apr 21, 2023 XIII National Workshop on Diagnostic Methods in Clinical Microbiology, JIPMER