Blood culture and sepsis

1. BLOOD CULTURE:THE GOLD
STANDARD IN SEPSIS
DIAGNOSIS
DR .NISHA SINGH
CONSULTANT MICROBIOLOGIST
PATHKIND LABS. PATNA
HICC HEAD, MGM HOSPITAL PATNA

2. AGENDA
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Definition
Burden of sepsis
Sources of sepsis
Biomarkers for sepsis
Blood cultures: gold standard
Rapid methods
References

3. .THE THIRD INTERNATIONAL CONSENSUS DEFINITIONS FOR SEPSIS AND SEPTIC SHOCK
(SEPSIS-3), PUBLISHED IN FEBRUARY 2016 BY AN INTERNATIONAL PANEL OF
PHYSICIANS, DEFINED SEPSIS AS “LIFE-THREATENING ORGAN DYSFUNCTION CAUSED
BY A DYSREGULATED HOST RESPONSE TO INFECTION.
BLOOD STREAM INFECTION BSI – POSITIVE BLOOD CULTURE IN A
PATIENT WITH SYSTEMIC SIGNS OF INFECTION; MAY BE EITHER PRIMARY
OR SECONDARY
SEPSIS – LIFE THREATENING ORGAN DYSFUNCTION CAUSED BY A
DYSREGULATED HOST RESPONSE TO INFECTION
SEPTIC SHOCK –SEVERE SEPSIS COMPLICATED BY PERSISTENT
ARTERIAL HYPOTENSION UNEXPLAINED BY OTHER CAUSES, DESPITE
ADEQUATE FLUID RESUSCITATION.

4. BURDEN OF SEPSIS
SEPSIS RANK INTOP 10 CAUSES OF DEATH
85% OF SEPSIS CASES OCCUR IN LOW-TO MIDDLE-INCOME
COUNTRIES
IN 2020, THEREWERE ESTIMATED 11 MILLION SEPSIS CASES
IN INDIAWITH CLOSETO 3 MILLION DEATHS
35-40 % OF SEPSIS PATIENTS IN INDIA DIE INTHE ICU
TREATMENT INCREDIBLY CHALLENGING WITHOUT KNOWING
THE PATHOGEN
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Antibiotics stewardship can
help in managing sepsis by by
implementation of right
antibiotics with right duration

5. SOURCE OF SEPSIS
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6. 2/23/2024 6

7. Obtain culture
Initiate appropiate antibiotic with in 1 hr if pt in shock
Initiate appropiate antibiotic with in 3 hr if pt is sepsis
Obtain baselin PCT CRP and LACTATE level
Daily pt reassesse and look for clinical and laboratory parameter
improvement after 3-5 full course of antibiotic
SOFA decrease by 2 or more point
Stop antibiotic when
5 full days of antibiotic
therapy
CRP decrease 50%
PCT decrease70- 80 %
7 days of full antibiotic
therapy regardless of
biomarker
Yes No
Drug related inadequate antibiotic converge
Diagnostic related :considerer differential diagnosis of infection
Route of administration ,antibiotic concentration in the
infectious site.
Resistance focus of infection ,MDR , Non bacterial infection
If clinically stable consider stopping antibiotic therapy after 7
full days : monitor clinical and laboratory deterioration

9. 1.OXYGEN:
Titrate O2 to saturations
of 94 -98% or 88-92% in
chronic lung disease
SEPSIS SIX
2.FLUIDS:
Start IV fluid
resuscitation if
evidence of
hypovolaemia
3.ANTIBIOTIC
Give IV antibiotic
according
to local antimicrobial
guidelines
1. CULTURES:
Take blood
cultures before
giving antibiotics
(if no significant
delay >45 mins)
2.BLOODS:
Check point of
care lactate & full
blood count
3.URINE OUTPUT:
Assess urine
output and
consider urinary
catheterisation
GIVE
3
TAKE
3

10. What does the physician
want from a blood culture?
• Sensitive results that detect the
clinically important organisms
• Rapid, timely results that can
direct therapy
• Accurate antimicrobial
susceptibility results that can
guide definitive therapy
What technical factors
impact culture sensitivity
and time to results?
• Method of blood collection – skin
disinfection, volume of blood, timing
of collection, delays in culture
• Growth of organisms – function of
organism growth properties (lag
phase, replication rate), presence of
antibiotics and other inhibitors in
blood, culture media, detection
method
SEPSIS DIAGNOSIS AND MANAGEMENT

11. GOLD STANDARD FOR DIAGNOSIS IS BLOOD
CULTURE
IDENTIFY ORGANISM
ANTIBIOTIC SENSITIVITY CAN BE PERFORMED
DE ESCALATE ANTIMICROBIAL AGENTS
STUDY OF NEW RESISTANCE MECHANISMS
IT HAS DIAGNOSTIC AND PROGNOSTIC VALUE

12. SEPSIS IS A COMPLEX ILLNESS INVOLVING BOTH INFECTION AND INFLAMMATION.
NORMALLY, THE BODY’S RESPONSE TO AN INFECTION IS TARGETED TO THE SITE
OF THE INFECTION. WITH SEPSIS, THE BODY’S RESPONSE, INSTEAD OF BEING
LOCALIZED TO THE SITE OF INFECTION, CAUSES SYMPTOMS TO OCCUR
THROUGHOUT THE BODY
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14. 2/23/2024 14

15. 100%
92%
85%
77%
70%
62%
54%
0
20
40
60
80
100
0 1 2 3 4 5 6 7
Survival
rate
Hours
WHEN A PATIENT IS IN SEPTIC SHOCK:
SURVIVAL RATE DECREASES BY 7.6% WITH EVERY 1 HOUR
DELAY IN DETECTION OF SPECIFIC PATHOGEN
Kumar A, Roberts D, Wood KE, Light B, Parrillo JE, Sharma S, Suppes R, Feinstein D, Zanotti S,
Taiberg L, Gurka D, Cheang M.; Duration of hypotension before initiation of effective antimicrobial therapy is the critical
determinant of survival in human septic shock. Crit Care Med, 2006: 34: 1589‐96

16. BLOOD VOLUME IMPACTS RECOVERY
MORE BLOOD = MORE POSITIVE IN BLOOD CULTURES
1
6
Volume of blood collected is directly proportional to recovery1
Every ml of blood increases sensitivity of BC by 3% in septic
patient
For Adults- At least 20ml blood should be drawn per
venipuncture
and divided between 2 bottles preferably one aerobic and
one anaerobic
For infants and children - Based on the child’s age and not
exceeding 1% of the patient’s total blood volume2

17. • IN ADULT PATIENTS WITH SUSPECTED BSIS, THE CURRENT RECOMMENDATION IS TWO TO
THREE BLOOD CULTURE SETS PER EPISODE WITHIN A 24-HOUR PERIOD.
• MULTIPLE SETS ENSURE ADEQUATE BLOOD VOLUME.
• SEVERAL STUDIES INDICATE INCREMENTAL YIELD IN 20ML. PATHOGEN YIELD WAS 73%
FROM FIRST BLOOD CULTURE SET, 90% FROM TWO SETS AND 98% FROM THREE
MORE THAN 99% FROM FOUR SETS.
PAIRED BLOOD CULTURE SETS
Blood culture – CLSI M47 (2022) An update

18. • AEROBIC AND ANAEROBIC BLOOD CULTURE BOTTLES, YIELDED MORE
STAPHYLOCOCCUS, ENTEROBACTERALES THAN AEROBIC BLOOD CULTURE
BOTTLES. PATHOGENIC YEASTS ARE RECOVERED EXCLUSIVELY FROM
AEROBIC BOTTLES
• A PERFECT PAIR OF AEROBIC BOTTLE AND LYTIC ANAEROBIC BOTTLE –
BETTER ISOLATION OF MOST OF THE BACTERIA OF PATHOGENIC
IMPORTANCE
• PAIRED CULTURES ALSO HELP IN DIFFERENTIATING CONTAMINANTS FROM
PATHOGENS
• PAIRED CULTURES HELP IN CONFIRMATION OF CLABSI
IMPORTANCE OF PAIRED BLOOD CULTURES

19. *NOTE: PO Antibiotics do not count towards the treatment of severe sepsis or septic shock; IV Abx ONLY!
Within 1 hour of Time of Presentation
Sepsis Facts
Examples of
commonly
used broad
spectrum
antibiotics

20. CURRENT AND EMERGING TECHNOLOGIES FOR RAPID
DIAGNOSIS
MALDI TOF
Syndromic Multiplex PCR
Panels
MICROARRAY

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DEFINITIONS CONFERENCE. INTENSIVE CARE MED 2003;29:530–8.
2. ANGUS DC, LINDE-ZWIRBE WT, LIDICKER J, CLERMONT G, CARCILLO J, PINSKY MR. EPIDEMIOLOGY OF SEVERE SEPSIS IN THE UNITED STATES:
ANALYSIS OF INCIDENCE, OUTCOME, AND ASSOCIATED COSTS OF CARE. CRIT CARE MED 2001;29:1303–9.
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DEPARTMENT GUIDELINES. ANN EMERG MED 2006;48:28-54.
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DEPARTMENT-BASED EARLY GOAL-DIRECTED THERAPY PROTOCOL FOR SEVERE SEPSIS AND SEPTIC SHOCK. CHEST 2007;132:425-32.
6. DELLINGER RP, ET AL. SURVIVING SEPSIS CAMPAIGN: INTERNATIONAL GUIDELINES FOR MANAGEMENT OF SEVERE SEPSIS AND SEPTIC SHOCK:
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CAREGIVERS, 2ND ED., VOL. 4, PP. 835–838. FARMINGTON HILLS, MI: GALE.
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10. NIEDERMAN MS (2004). PNEUMONIA, INCLUDING COMMUNITY-ACQUIRED AND NOSOCOMIAL PNEUMONIA. IN JD CRAPO ET AL., EDS., BAUM'S
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REFERENCES