Blood stream infection department of microbiology.pdf

Laboratory diagnostics, treatment, etiology, prognosis

1. Microbiology
Seminar Activity
Guided By –Dr.SakshiPatel Mam
Presented By-Harsh Kumar Batham, HimanshiKushwah, Jahnavi
Pawar, HarshitPanwar, JyotiNagda, JyotiChouchan,Irfan mansuri,
HimanshiChoubey, JaspalThakur

2. Blood Stream Infections
oBloodstream infections (BSI) refer to the presence of
microorganisms in blood, which constitute one of the most serious
situations among infectious diseases; as they are a threat to every
organ in the body.
oMicrobial invasion of bloodstream can have serious immediate
consequences such as shock, multiple organ failure, and DIC
(disseminated intravascular coagulopathies)
o Therefore, timely detection of the causative agent is one of ETIC the
most important goals of the microbiology laboratory.
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3. Types of Bacteremia
Transient
bacteremia:
may occur
spontaneously
or with minor
events.
These circumstances
may also lead to
septicemia;
bacteria are cleared from
blood by the host immune
mechanisms
Continuous
bacteremia:
the organisms are
released into the
bloodstream at a
fairly constant rate.
occurs in conditions
such as: Septic shock,
endocarditis and other
endovascular
infections
Intermittent
bacteremia:
bacteria are released
into blood
intermittently
pneumonia,
septic arthritis
and
osteomyelitis.
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4. Etiological Agents of
BSI
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5. •Gram-positive cocci—staphylococci, beta-hemolytic streptococci, enterococci and pneumococci
•Gram-negative cocci—meningococci
•Gram-positive bacilli—Bacillus anthracis and Listeria
•Gram-negative bacilli—E. coli, Klebsiella, Enterobacter, non-fermenters (e.g. Pseudomonas, Acinetobacter, Burkholderia,
Stenotrophomonas), Haemophilus, Aeromonas, etc.
•™ Anaerobes—Bacteroides.
Bacteria
•Human immunodeficiency virus (HIV) and other
•human retroviruses—attack CD4 T lymphocytes and macrophages
•™ Agents of hemorrhagic fever such as dengue, chikungunya, Ebola, Marburg, Lassa, yellow fever, and other viruses—
•™ Epstein-Barr virus: Invades lymphocytes. It causes
•™ Cytomegalovirus: Invades monocytes, poly-
Viruses
•Candida - Candida albicans and non-albicans Candida species such as C. tropicalis, C. parapsilosis and C. auris
•Agents of systemic mycoses (Histoplasma, Blastomyces, Coccidioides, and Paracoccidioides)
•Cryptococcus
Fungi
•Plasmodium and Babesia
•oxoplasma gondii, amastigote forms of
•Leishmania, and trypomastigote forms of Trypanosoma
•Schistosoma
Parasites
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6. •Fever or hypothermia with/without chills
and rigors
•Hyperventilation -excess loss of CO2 and
•Subsequent, respiratory alkalosis
•Skin lesions, change of mental status and
diarrhea.
Sepsis
• hypotension, DIC and multi-organ failure
•(e.g. acute respiratory distress,
•renal failure, tissue destruction, etc.).
Septic shock:
CLINICAL MANIFESTATIONS
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7. DEFINATION
•Acute bacterial infection that is potentially fatal multisystem illness
caused by Salmonella species enterica subspecies enterica serotype Typhi
[typhoid fever] and,
• S.Paratyphi A,B, and C.[Paratyphoid fever]
ETIOLOGY
Transmission – faecal-oral route , via contaminated food or water
Close contact with patients or carriers
Flies and cockroaches
Enteric Fever
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8. Lab Diagnosis specimen collection
•Blood culture
•Bone marrow
•Duodenal
aspirate culture
1
st
week of
illness
•Serum
2
nd
week of
illness •Urine
•Stool
3
rd
and 4
th

week of illness
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9. Culture
Isolation
•Blood and Bone Marrow
•Conventional –BHI
broth/agar
•Automated –BACTEC or
BacT/ALERT
•Stool
•Enrichment broth –
Selenite F, tetrathionate,
gram negative
•Low selective medium –
MacConkeyAgar
•Highly selective Medium –
DCA, XLD, Wilson
Blair’s Bismuth sulphite
medium
•Culture smear motility
•Motile , Gram negative
Bacilli
Biochemical
Identifications
•Catalase +
•Oxidase -
•Indole -
•Citrate +/-
•Urease -
•TSI K/A gas +
[except S.typhi]
Serum antibody
detection [WIDAL]
•S.Typhi – TO,TH
•S. ParatyphiA –
TO,AH
•S. ParatyphiB –TO,
BH
•O Ab –granular
chalky clumps
•H Ab –cottony
woolly clumps
Following
•Antigen detection
of serum / urine –
ELISA
•Molecular methods
–PCR
•Antimicrobial
Susceptible
Testing[AST]
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10. Treatment
•3
rd
generation cephalosporin : Ceftriaxone
•Azithromycin
•Fluoroquinolones : Ceprofloxacin
•For carriers – Ampicillin/ amoxicillin+Probenecid
{6 weeks}
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11. CLABSI
CLABSI – Central Line Associated Blood Stream Infection
•it is a development of blood stream infection
•Seen in hospitalized patient
•Attributed to presence of central line
•CLBS -> for surveillance
CENTRAL LINE
•It is a intravascular device which terminates in the great vessels
•PURPOSE – Central venous pressure monitoring , also the site of
administration of drugs
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12. Intrinsic Contamination
[intraluminal source]
Extrinsic Contamination [extra
luminal source]
Contamination during device or
fluid production
Contamination at the time of
insertion
Due to defect during
manufacture May cause
outbreaks
Poor sterile precautions during drug
or IV fluid admixture
Most common causative agents
include Klebsiella, Enterobacter
or Pseudomonas
Most common causative agents
include skin commensals like CONS
and S. aureus
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13. Causative microorganisms are usually Gram-negative bacteria
growing in the infuscate, such as Klebsiella spp., Enterobacter spp., or
Pseudomonas spp.
The other source of contamination may be introduced during therapy
and can occur due to
(i)contamination of the IV catheter at the time of insertion,
(ii)break in aseptic technique during drug admixture or
administration of the IV fluid,
(iii)contamination of part of the administration system, and/or
(iv)catheter contaminated with the hands of the operator.
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14. CLINICAL MANIFESTATIONS
•Foreign Body Reaction –around the catheter insertion site
•Colonization of the organism - microbial adherence
•Biofilm formation on catheter surface: coagulase-negative staphylococci, S.
aureus, Pseudomonas aeruginosa, and Candida species.
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15. 14

16. •Presence of fever, chills, rigor or
hypotension after the insertion of CL
•catheter site infection erythema,
tenderness, warmth, swelling at the
catheter exit site
Clinical
Criteria
•Blood culture from central line and
peripheral line
•Central line blood culture bottle bags >
2hrs earlier to peripheral line blood
culture ( i.edifferential time to
positivity > 2hrs )
Microbiological
criteria:
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17. TREATMENT :
-Systemic antimicrobial therapy and removal of central line.
-Started as soon as clinical suspicion is made modified later based
on susceptibility report.
ANTIBIOTIC LOCK THERAPY ( ALT ) – In case of infection
which CoNS ,
Limited venous access , history of recurrent CLABSI.
- Involves instillation of highly concentration antibiotics solution
into central line lumen and is left to deep which in lumen for short
period.
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18. DEFINATION
•Oppurtunistic fungal [yeast] infection that may affect mouth,
vagina, skin, stomach, urinary tract.
•Caustive agent – Candida, a yeast like fungus that produces
pseudohyphae.
•Various species – Candida albicans [most pathogenic] , C.tropicalis,
C.glabrata.
Systemic Candidiasis
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19. Lab Diagnosis and Specimen collection
DIRECT
MICROSCOPY :
•Gram-positive oval
budding yeast cells
with pseudohyphae.
CULTURE ON
SDA :
•Produces creamy
white pasty colonies
TESTS FOR SPECIES
IDENTIFICATION :
•German tube test (+ candidiasis )
•Dalmauplate culture -chlamydosporeproduction
•Growth at 45*C ( + C. albicans)
•Carbohydrate assimilation test and carbohydrate
fermentation test
•Automated system {MALDI-TOF, VITEK}
•Molecular method -PCR
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20. IMMUNODIAGNISIS :
•Antibody detection against cell wall mannan antigen.
•Antigen detection -cell wall mannanand cytoplasmic antigens.
Enzyme detection
• e.g. enolase
Detection of metabolites
•, e.g. mannitol and arabinotioL
β-d-GLUCAN ASSAY :
•Marker of invasive fungal infection
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21. CANDIDIASIS TREATMENT
•The antifungal drugs recommended depends upon the type of
candidiasis.
1.Cutaneous candidiasis or oral thrush : the drug of choice is
topical azole.
2.Esophageal and vulvovaginal candidiasis : the drug of choice
is oral fluconazole or caspofungin or voriconazole.
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22. REFERENCE
✓Essentials Of Medical Microbiology By Apurba S Sastry 4
th

Edition
✓Manual of Infection Prevention and Control FOURTH
EDITION Nizam Damani
✓PubMed® - https://pubmed.ncbi.nlm.nih.gov/
✓Picture courtesy – www.google.com
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