Culture Media in Microbiology

Question 1

Define Bacteremia:

Answer 1

• Bacteremia: bacteria in the blood and can be present without disease

Question 2

Define Septicemia:

Answer 2

• Septicemia: bacteria or its toxins found in the blood cause harm to the patient
• Bacteria are actively multiplying & metabolizing, producing toxins
• Various toxins released may lead to septic shock with fever, chills, lowered BP, respiratory distress, & disseminated intravascular coagulation (DIC)

Question 3

Define Fungemia:

Answer 3

Fungemia: fungal infection in the blood stream
- yeast and other fungal elements grow slower than bacteria

Question 4

What are blood cultures incubated at?

Answer 4

• They are incubated at 35-37°C for 5 days

Question 5

What is blood agar incubated at?

Answer 5

• 1. Blood Agar incubated in CO2 at 35°C for 5 days

Question 6

What is CHOC agar incubated at?

Answer 6

• 2. CHOC agar incubated in CO2 at 35°C for 5 days

Question 7

What is Brucella agar incubated at?

Answer 7

• 3. Brucella agar incubated AnO2 at 35°C for 5 days

Question 8

What time frame is the gram stain read at reported at by the sound of the positive alarm?

Answer 8

• The gram stain is always read and reported to the physician within 1 hour of the positive alarm

Question 9

What can cause a false positive blood culture?

Answer 9

-Can arise from overfilled bottles
- Increased white blood cell counts

Question 10

How long do you have to replace the BC bottle if it’s still negative?

Answer 10

• If still negative, you have 30 minutes to replace the bottle into the analyzer for the remainder of its total incubation period

Question 11

When would you suspect BC conataminatin?

Answer 11

• Only 1 bottle from a set is positive
• The bottle flags as positive near the end of its 5 day incubation period
• The organism growing is a Coagulase Negative Staphylococcus, Bacillus spp., Corynebacterium spp., Cutibacterium spp.

Question 12

What are 4 sterile body fluids and tissues?

Answer 12

• Sterile: CSF, synovial, intraoperative fluids or tissues, etc.

Question 13

What are 3 non-sterile body fluids and tissues?

Answer 13

• Non-sterile: drainages, skin surface biopsies, etc.

Question 14

What are 3 ways a gram stain for fluids can be made?

Answer 14

The gram stain for fluids can be made in a variety of ways:
- Direct inoculation onto a glass slide
- The fluid itself can be centrifuged if enough received
- The fluid is cytospun onto a glass slide

Question 15

What ways can