Blood Cultures Flashcards
Obj. 1: Define the following terms: bacteremia, fungemia, viremia, pseudobacteremia
Bacteremia: presence of bacteria in the blood
Fungemia: presence of fungi in the blood
Viremia: presence of a virus in the blood
Pseudobacteremia: presence of bacteria in the blood from contamination during collection
Obj. 1: Define the following terms: septicemia
Septicemia: multiplying organisms in the bloodstream plus the presence of symptoms
Obj. 1: Define the following terms: SIRS (Systemic Inflammatory Response Syndrome)
SIRS (Systemic Inflammatory Response Syndrome): criteria for the designation of SIRS requires at least two (2) of these —
- Temperature
- Heart Rate
- Respiratory rate
- WBC count
Obj. 1: Define the following terms: sepsis
Sepsis: dysregulation of the host response to an infection accompanied by organ dysfunction
Obj. 1: Define the following terms: septic shock
Septic shock: sepsis plus cardiovascular dysfunction
Obj. 1: Define the following terms: endocarditis
Endocarditis: inflammation of the heart due to a bacterial infection
Obj. 1: Define the following terms: Disseminated intravascular coagulation (DIC)
Disseminated intravascular coagulation (DIC): abnormal blood clotting throughout the body’s blood vessels
Obj. 2: List common symptoms associated with possible septicemia
- Fever
- Chills
- Tachycardia
- Hyperventilation
- Toxicity
- Prostration
- Mental confusion
- Dizziness
Obj. 3: List five (5) risk factors associated with bacteremia
- Age of the patient
- Increased use of invasive procedures
- Antimicrobial resistance
- Diagnostic criteria and coding practices
- Decreased immune competency of certain patient
populations
Obj. 4: Classify bacteremia by its site of origin (primary and secondary bacteremia)
Primary bacteremia: intravascular
Secondary bacteremia: extravascular
Obj. 5: Classify bacteremia by the duration of the bacteremic episode (transient, intermittent, continuous)
Transient: “passing through,” occurs when bacteria enter the blood after manipulation of tissue with normal flora
Intermittent: infected site sporadically releasing bacteria into the blood (“seeding”)
Continuous: intravascular source and are consistently present in the bloodstream
Obj. 6: Discuss situations that may result in transient, intermittent, continuous, primary, and secondary bacteremia
Transient: dental work, endoscopy
Intermittent: abscess
Continuous: biofilm on infected IV catheter
Primary: infected cardiac valve, infected IV catheter
Secondary: abscess, pneumonia patients, UTI
Obj. 7: Discuss the expected lab test results for patients with septicemia for the following tests: Platelet count, coagulation tests, WBC count, lactate, blood glucose, CRP, and PCT (Procalcitonin)
Plt. count: decreased
Coag tests: High PTT and PT
WBC count: increased (can be decreased)
Lactate: increased
Glucose: increased or decreased
CRP: increased
PCT: increased
Obj. 8: Recognize that one blood culture “set” consists of two (2) blood culture bottles (aerobic and anaerobic)
Recognize that one blood culture “set” consists of two (2) blood culture bottles (aerobic and anaerobic)
Obj. 9: Describe the purpose of sodium polyanetholsulfonate (SPS) and resins (ARD antimicrobial removal devices)
Sodium Polyanetholsulfonate (SPS): anticoagulant
Resins: binds antimicrobials
Obj. 10: Discuss the proper method of collecting (including sterile collection, recommended maximum number of sets, timing of collection, amount of blood, and what to do if an IV is present, patient is receiving antimicrobials, or spiking a fever) a blood specimen for bacteriologic culture
Obj. 11: Correlate the number, timing, ratio of patient blood to culture broth, and volume of specimens with optimal recovery of organisms for meaningful clinical use
Sterile collection
- Clean skin w/ isopropyl alcohol
- Follow with iodine/Chlorhexidine in circles
- Remove residue with alcohol pad
Recommended maximum number of sets
- 3 culture sets within 24 hours
Timing of collection
- Acute: multiple cultures in the first 6-12 hours
- Chronic: 2-3 cultures per day for 3-4 days
Amount of blood
- Blood to medium ratio: 1:10
- Pediatric venipuncture: 2-6 mL (BLC: 1-3 mL)
- Adult venipuncture: 16-20 mL (BLC: 8-10 mL)
What to do if an IV is present
- If both arms have IV sites, draw below IV
Patient is receiving antimicrobials
- Collect cultures before antimicrobial therapy
Spiking a fever
- Collect before fever spike
Obj. 12: Discuss the proper method for transporting and incubating a blood specimen for bacteriologic culture
Transport to lab at room temperature ASAP; if delayed, can be held at room temp for 48 hours
Incubate 35 +/- 2 deg. C for 5-7 days ambient air
Obj. 13: Describe the proper blood culture procedure for possible brucellosis [include the Bactec FX and manual biphasic media (Ruiz Casteneda) in your answer]
Bactec FX
- Incubate for 14 days
Manual biphasic media (Ruiz Casteneda)
- Incubate 35 +/- 2 deg. C for 6 weeks and terminally subculture
Obj. 14: Discuss the basic principles of the Wampole (DuPont Isolator) Lysis Centrifugation Method
RBCs and WBCs are lysed to release fungi and intracellular pathogens — centrifuge and plate sediment/pellet
Obj. 30: Evaluate a Gram stained smear of a blood culture bottle to determine the likely organism(s)
Actinomyces
Obj. 31: Correlate the image with a clinical scenario(s)
Recognize which is a common contaminant
Actinomyces
- Tissue necrosis and dissemination to brain
Obj. 30: Evaluate a Gram stained smear of a blood culture bottle to determine the likely organism(s)
Actinomyces
Obj. 31: Correlate the image with a clinical scenario(s)
Recognize which is a common contaminant
Actinomyces
- Tissue necrosis and dissemination to brain
Obj. 30: Evaluate a Gram stained smear of a blood culture bottle to determine the likely organism(s)
Actinomyces
Obj. 31: Correlate the image with a clinical scenario(s)
Recognize which is a common contaminant
Actinomyces
- Tissue necrosis and dissemination to brain
Obj. 30: Evaluate a Gram stained smear of a blood culture bottle to determine the likely organism(s)
Bacillus (GP and decolorized)
Obj. 31: Correlate the image with a clinical scenario(s)
Recognize which is a common contaminant
Bacillus (GP and decolorized)
COMMON CONTAMINANT!
- Anthrax
- Food poisoning (meat, chicken, fried rice, etc.)
Obj. 30: Evaluate a Gram stained smear of a blood culture bottle to determine the likely organism(s)
Bacillus
Obj. 31: Correlate the image with a clinical scenario(s)
Recognize which is a common contaminant
Bacillus
COMMON CONTAMINANT!
- Anthrax
- Food poisoning (meat, chicken, fried rice, etc.)
Obj. 30: Evaluate a Gram stained smear of a blood culture bottle to determine the likely organism(s)
Bacteroides fragilis (pleomorphic)
Obj. 30: Evaluate a Gram stained smear of a blood culture bottle to determine the likely organism(s)
Bacteroides fragilis (vacoulated)
Obj. 30: Evaluate a Gram stained smear of a blood culture bottle to determine the likely organism(s)
Campylobacter
Obj. 30: Evaluate a Gram stained smear of a blood culture bottle to determine the likely organism(s)
Campylobacter
- Diarrhea
Obj. 30: Evaluate a Gram stained smear of a blood culture bottle to determine the likely organism(s)
Clostridium clostridioforme (GNR) [top]
Clostridium perfringens (GPR) [bottom]
Obj. 31: Correlate the image with a clinical scenario(s)
Recognize which is a common contaminant
Clostridium clostridioforme (GNR) [top]
Clostridium perfringens (GPR) [bottom]
- C. perfringens
- Gas gangrene
Obj. 30: Evaluate a Gram stained smear of a blood culture bottle to determine the likely organism(s)
Corynebacterium spp.
Obj. 31: Correlate the image with a clinical scenario(s)
Recognize which is a common contaminant
Corynebacterium spp.
COMMON CONTAMINANT!
- Diphtheria
Obj. 30: Evaluate a Gram stained smear of a blood culture bottle to determine the likely organism(s)
Enterococcus
Obj. 31: Correlate the image with a clinical scenario(s)
Recognize which is a common contaminant
Enterococcus
- Acute endocarditis
- GI perforation
- Infected IV catheter
Obj. 30: Evaluate a Gram stained smear of a blood culture bottle to determine the likely organism(s)
Streptococcus mitis
Obj. 30: Evaluate a Gram stained smear of a blood culture bottle to determine the likely organism(s)
Fusobacterium nucleatum
Obj. 31: Correlate the image with a clinical scenario(s)
Recognize which is a common contaminant
Fusobacterium nucleatum
- Assoc. with infections of mouth (human bites, lung abscesses, pleural cavity, brain abscess)
Obj. 30: Evaluate a Gram stained smear of a blood culture bottle to determine the likely organism(s)
Fusobacterium mortiferum
Obj. 31: Correlate the image with a clinical scenario(s)
Recognize which is a common contaminant
Fusobacterium mortiferum
- Assoc. with infections of mouth (human bites, lung abscesses, pleural cavity, brain abscess)
Obj. 15: Discuss the organisms that are best isolated from the lysis centrifugation
- Bartonella
- Yeast/fungi
- Mycobacteria
Obj. 16: Define continuous monitoring blood culture systems
Blood culture systems that continuously monitor blood culture bottles for growth of organisms
Obj.17: Discuss the basic principles of the BACTEC systems
- As organisms grow in the blood culture bottles, they release CO2
- A dye in the sensor of the bottom of the bottle reacts with the increased CO2 and releases a fluorescent signal
- A photo detector measures the fluorescence and will alarm if it surpasses a certain parameter
Obj. 18: Briefly discuss the principles of the VersaTREK and BacT/ALERT systems
VersaTREK: Detects changes in the air pressure above the blood culture bottle
BacT/ALERT: Detects changes in pH due to release of CO2
Obj. 19: What steps should be taken after the BACTEC indicates a blood culture bottle is positive
- Prepare and exam gram stain from blood culture bottle
- CALL THE PHYSICIAN!
- Based on GS, set up appropriate culture media, biochemicals, rapid testing
Obj. 20: Discuss the advantages of methanol fixation vs. heat fixation for direct smear GS
Methanol fixation keeps the cell morphology intact
Obj. 21: Determine which media should be set up on ALL positive blood cultures
- BAP, CHOC, AnaBAP
Obj. 30: Evaluate a Gram stained smear of a blood culture bottle to determine the likely organism(s)
Klebsiella pneumoniae
Obj. 31: Correlate the image with a clinical scenario(s)
Recognize which is a common contaminant
Klebsiella pneumoniae
- Pneumonia
Obj. 30: Evaluate a Gram stained smear of a blood culture bottle to determine the likely organism(s)
Lactobacillus
Obj. 31: Correlate the image with a clinical scenario(s)
Recognize which is a common contaminant
Lactobacillus
- Prevents colonization/overgrowth of pathogens/normal flora
Obj. 30: Evaluate a Gram stained smear of a blood culture bottle to determine the likely organism(s)
Listeria monocytogenes
Obj. 31: Correlate the image with a clinical scenario(s)
Recognize which is a common contaminant
Listeria monocytogenes
- Listerosis: pkg. lunch meats, hot dogs, dairy products; pregnant women - stillborns, spontaneous abortions
Obj. 30: Evaluate a Gram stained smear of a blood culture bottle to determine the likely organism(s)
Propionibacterium acnes
Obj. 31: Correlate the image with a clinical scenario(s)
Recognize which is a common contaminant
Propionibacterium acnes
COMMON CONTAMINANT!
- CNS shunt infection
- Prosthetic joint infection
Obj. 30: Evaluate a Gram stained smear of a blood culture bottle to determine the likely organism(s)
Staphylococcus aureus
Obj. 31: Correlate the image with a clinical scenario(s)
Recognize which is a common contaminant
Staphylococcus aureus
- Pneumonia
- Acute endocarditis
- Infected IV Catheters
Obj. 30: Evaluate a Gram stained smear of a blood culture bottle to determine the likely organism(s)
Streptococcus pneumoniae (GP)
Obj. 31: Correlate the image with a clinical scenario(s)
Recognize which is a common contaminant
Streptococcus pneumoniae (GP)
- Community acquired pneumonia
- Acute endocarditis
- Meningitis
Obj. 30: Evaluate a Gram stained smear of a blood culture bottle to determine the likely organism(s)
Streptococcus pneumoniae (GP and decolorized)
Obj. 31: Correlate the image with a clinical scenario(s)
Recognize which is a common contaminant
Streptococcus pneumoniae (GP and decolorized)
- Community acquired pneumonia
- Acute endocarditis
- Meningitis
Obj. 30: Evaluate a Gram stained smear of a blood culture bottle to determine the likely organism(s)
Vibrio vulnificus
Obj. 31: Correlate the image with a clinical scenario(s)
Recognize which is a common contaminant
Vibrio vulnificus
Consumption of contaminated seafood (raw oysters)
Obj. 22: Outline the algorithm for identifying organisms from a positive blood culture, including: GS specific preliminary testing (biochemicals/direct molecular techniques), confirmation testing, and susceptibility reporting
Obj. 23: Summarize how the use of rapid molecular testing, such as the BioFire FilmArray BCID Panel can improve patient outcomes
Simultaneous detection and identification of bacteria and resistance markers allowing a decrease in TAT for targeted therapy
Obj. 24: Briefly discuss the basic principles of PNA FISH, Verigene, MALDI-TOF with sepsityper, and GeneXpert MRSA testing
Verigene: PCR — gram stain dependent
PNA FISH: Fluorescent in-situ Hybridization — detection of yeast strains
MALDI-TOF w/ sepsityper: lysing, washing, and centrifugation steps to perform directly on sample for ID
GeneXpert MRSA: Real-time PCR for MRSA/SA
Obj. 25: Correlate the most common organism(s) involved in septicemia with associated underlying diseases:
- Bacterial pneumonia
- Streptococcus pneumoniae
- S. aureus
- PSA
- Klebsiella spp.
- Enterobacter spp.
Obj. 25: Correlate the most common organism(s) involved in septicemia with associated underlying diseases:
- Acute endocarditis
- S. aureus
- Enterococcus spp.
- Streptococcus pneumoniae
Obj. 25: Correlate the most common organism(s) involved in septicemia with associated underlying diseases:
- Subacute endocarditis
- Coag. Neg. Staphylococcus
- Viridans Streptococcus
- Abiotrophia spp./Granulicatella
Obj. 25: Correlate the most common organism(s) involved in septicemia with associated underlying diseases:
- GI cancer
- Clostridium septicum
- Group D Streptococcus (S. bovis)
Obj. 25: Correlate the most common organism(s) involved in septicemia with associated underlying diseases:
- GI perforations
- E. coli
- Enterococcus spp.
- Anaerobes
- Bacteroides fragilis grp.
- Fusobacterium spp.
- Clostridium spp.
Obj. 25: Correlate the most common organism(s) involved in septicemia with associated underlying diseases:
- UTI
- E. coli
Obj. 25: Correlate the most common organism(s) involved in septicemia with associated underlying diseases:
- Tooth abscess
- Mouth flora
Obj. 25: Correlate the most common organism(s) involved in septicemia with associated underlying diseases:
- Meningitis
- Neiseseria meningitis
- Streptococcus pneumoniae
Obj. 25: Correlate the most common organism(s) involved in septicemia with associated underlying diseases:
- Intravascular catheter
- Skin flora (CoNS, P. acnes)
- S. aureus
- Enterococcus spp.
Obj. 26: List Gram positive and Gram negative organisms that may be observed on a Gram stained smear from a blood culture bottle but would NOT grow on SBA and, with some organisms, not on CHOC
- Haemophilus
- Camplyobacter
- Abiotrophia spp./Granulicatella
Obj. 27: Identify (by image or name) the most common contaminants found in blood cultures
- Coag Neg Staph
- Corynebacterium spp.
- P. acnes
- Viridans Strep.
- Micrococcus
- Bacillus spp. (environmental contaminant)
Obj. 28: Recommend approaches that could be used to determine whether an isolate is a skin contaminant or a pathogen
- Is it skin flora?
- Is it only in one bottle (requires multiple draws)?
- Delayed growth?
Review Question: Once the initial Gram stain is read, the technologist should call the doctor. Then, any further plates and tests should be set up. What media and additional biochemical should be set up based on the following Gram stains?
- GPC in clusters
SBA, CHOC, ABAP, BioFire, Coagulase tube
Review Question: Once the initial Gram stain is read, the technologist should call the doctor. Then, any further plates and tests should be set up. What media and additional biochemical should be set up based on the following Gram stains?
- GPC in chains
SBA, CHOC, ABAP, BioFire, Bile Esculin, NaCl broth, Opt disk
Review Question: Once the initial Gram stain is read, the technologist should call the doctor. Then, any further plates and tests should be set up. What media and additional biochemical should be set up based on the following Gram stains?
- GNR
SBA, CHOC, MAC, CNA, ABAP, BioFire
Review Question: Once the initial Gram stain is read, the technologist should call the doctor. Then, any further plates and tests should be set up. What media and additional biochemical should be set up based on the following Gram stains?
- GPC
SBA, CHOC, ABAP, BioFire
(If resembles lactobacillus → TJ plate) (If resembles Bacillus → PEA)