microbiological aspects in sepsis
TRANSCRIPT
Microbiological aspects of sepsis
Capt Mohammed Ashraf AliMD (Microbiology)
Outline of Presentation
• Samples
–Collection And Transport
–Processing of sample
• Biomarkers Of Sepsis
• Molecular Based Techniques
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Clinical suspicion of SEPSIS
Foci of infection
Present Not known
BLOOD CULTURE• Grams staining• Culture of sample
from the foci+
• Blood culture
Choice of sample
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Blood Culture
VolumeBefore
antibiotic initiation
Disinfect1 Aerobic
1 Anaerobic
Key points
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Volume of blood• 1:5 ratio - blood to broth• < 10 years : 1 ml of blood for
every year of life• > 10 years: 20 ml
Disinfection• 2% Chlorhexidine/70% ethyl
alcohol• 2% Tincture Iodine (except in
children)
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Outline of Presentation
• Samples
–Collection And Transport
–Processing of sample
• Biomarkers Of Sepsis
• Molecular Based Techniques
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Biomarker Candidates• Multiple
• Biomarkers commonly found in the literature– Lactate levels–Pro-calcitonin levels–C-Reactive Protein
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Lactate to Diagnose Sepsis?
• End-product of anaerobic
glycolysis
• Increased in various settings:
– Excessive energy demands
– Tissue hypoperfusion
(shock)
Glycolysis
pyruvate
CoA lactate
ATP generation
Diminished ATP
Cell Death9Md Ashraf Ali
Lactate levels in diagnosis
• Container: Sodium Fluoride (gray cap)
• Volume reqd : 1 mL plasma
• Special Handling:
No tourniquet.
Place on ice immediately.
• Deliver within 15 minutes.
• Analytic Time: 2 hours
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Procalcitonin
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Procalcitonin levels in diagnosis
• Container: Sterile Vaccutainer
• Volume req: 0.5 mL serum
• Analytic Time: 4 hours
• Test Usage:
– Diagnosis and monitoring of sepsis and septic shock
– monitoring response to antibacterial therapy.12
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• Detection limit: 0.05mg/L
• Accurate and reliable detection
• Sensitivity - 84% and specificity – 81%
Is Procalcitonin an Ideal Biomarker?
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Which biomarker and when?
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MOLECULAR BASED TECHNIQUES
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DETECTION OF BACTEREMIA AND FUNGEMIA
• Samples directly taken from patients
• PCR- simultaneous detection of organism along
with resistant genes (oxacillin, vanco,
carbapenems)
• Results – few hours
• Not cost effective
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Summary Test Sample Volume Container
Blood culture Whole blood
10ml Nutrient medium
Lactate assay Plasma 1 ml Sodium Fluoride (gray tube)
Procalcitonin Serum 0.5ml Sterile vaccutainer
C-reactive protein
Serum 0.5ml Sterile vaccutainer
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THANK YOU