Ch. 38: Equipment & Supplies Flashcards
Why is laboratory safety so important when in a microbiology laboratory?
Most of the microorganisms encountered are potentially pathogenic, and many are zoonotic
Laboratory coats should be washed how often in hot water and strog bleach?
At least weekly
How are spilled cultures cleaned up?
Treated with disinfectant and allowed contact for 20 minutes before they are cleaned up
Nondisposable wire loops that have been contaminated with microbes must be _______ immediately after use
Flamed
What is the primary piece of equipment needed in a microbiology laboratory?
A good-quality incubator
Needed supplies for collecting and preparing bacterial and fungal samples
- Sterile cotton-tipped applicators
- Dull scalpel blades, scissors, and forceps
- 3-20 mL syringes and 21-25 gauge needles
- Sterile ET tube or jugular or urinary catheter
- Collection tubes and preservatives
- Rayon swab in a transport media (Culturette)
- Glass slides and coverslips
- Inoculating loops or wires and 10 mL calibrated loops
- Bunsen burner or alcohol lamp
- Candle jar or anaerobe jar
- A variety of culture media (Plated and broth)
- Antibiotic disks and dispensers
- Gram stain
- “Discard jar”
- Wooden tongue depressors for handling feces
- Racks to hold tubes and bottles
- Refrigertor “cold packs” and polystyrene shipping containers for samples
What is a culture medium/media?
Any material solid or liquid that can support the growth of microorganisms
What forms of media are available for bacteriology?
Dehydrated powder, prepared agar plates, or ready to use liquid media for biochemical tests
What are the two types of solidifying agents used in the preparation of solid media?
Agar and gelatin
Agar definition
A gelatinous substance obtained from various kinds of red seaweed (agarophytes**) and used in biological culture media and as a thickener in foods
Gelatin defintion
A virtually colorless and tasteless water-soluble protein prepared from collagen (animal tissues)
Agar plates should be kept refrigerated at what degree celcius?
5-10
Why must plates be kept away from the internal walls of the refrigerator?
Contact with the jacket can freeze and ruin the media
How many general types of culture media are there?
6
What are the six types of general media used?
- Transport media
- General purpose media
- Enriched media
- Selective media
- Deifferential media
- Enrichment media
What types of media are those that contain multiple types of media in a single culture plate?
Modular media; these are common
General purpose media is also known as what?
Nutrient media; media is not commonly used
What is enriched media used for?
Formulated to meet the requirements of the most fastidious pathogen
What does enriched media contain?
They are basic nutrient media with extra nutrients added, such as blood, serum, or egg. This includes blood or chocolate agar
What is selective media made of?
Contain antibacterial substances, such as bile salts or antimicrobials, that inhibit or kill all but a few types of bacteria
What is an example of selective media?
MacConkey agar
What is differential media used for?
Used to allow bacteria to be differentiated into groups based on their biochemical reactions on the medium
What is an example of a differential media?
Simmons citrate
What is enrichment media used for?
Liquid media that favor the growth of a particular group of organisms. They contain nutrients that encourage the growth of the desired organisms or that contain inhibitory substances that suppress competitors
What are examples of enrichment media?
Tetrathionate broth and Selenite broth
What is transport media used for?
Designed to keep microbes alive while not encouraging growth and reproduction
A Culturette used for specimen collection is what type of media?
Transport media
What type of media is blood agar?
Acts as an enriched and differential media
What is the most commonly used blood agar?
Trypticase soy agar with sheep blood
How can blood agar act as an enriched and differential media?
Because four distinct types of hemolysis can be detected on blood agar
What are the four types of hemolysis that can occur on blood agar?
Alpha, Beta, Gamma, and Delta hemolysis
What is Alpha-hemolysis?
Partial hemolysis that creates a narrow band of greenish or slimy discoloration around the bacterial colony
What is Beta-hemolysis?
Complete hemolysis that creates a clear zone around the bacterial colony
What is Gamma-hemolysis?
Hemolysis that produces no change in the appearance of the medium and no hemolysis around colonies
What is another word for hemolysis?
Hematolysis
What is Delta-hemolysis?
A zone of hemolysis surrounded by a narrow zone of hemolysis around a bacterial colony
What is another name for Delta-hemolysis?
Double-zone hemolysis
Bacteria can be classified on the basis of their patterns of _______ in blood agar
Hemolysis