Microbiology Lab Practical

Study Notes

The experiment involved streaking samples on different types of plates, including environmental and skin/mucous membrane plates.

Trends observed during the experiment are not explicitly stated in the provided text.

Alpha hemolysis: partial breakdown of red blood cells, resulting in a greenish tint around the colony.
Beta hemolysis: complete breakdown of red blood cells, resulting in a clear zone around the colony.
Gamma hemolysis: no breakdown of red blood cells, resulting in no visible change around the colony.

Four modes of transmission:
- Direct contact: physical contact between an infected individual and a susceptible host.
- Indirect contact: contact with a contaminated fomite that has been touched by an infected individual.
- Airborne transmission: transmission through the air, such as through coughing or sneezing.
- Vector transmission: transmission through an intermediate agent, such as an insect.

Aseptic technique is used to prevent contamination of microorganisms in laboratory settings
Key steps include:
- Flame sterilization of equipment (e.g. loop)
- Flaming the openings of test tubes to eliminate transient microorganisms
- Working in a clean and sanitized environment

Flame sterilization of a loop involves:
- Holding the loop in a Bunsen flame until it is red hot
- Allowing the loop to cool before use

Conditions for incubating plates/cultures:
- In a controlled environment (e.g. temperature, humidity)
- For a specified period of time (e.g. 24 hours)
Standard conditions for incubating bacterial cultures:
- 37°C (98.6°F)
- Aerobic environment

Cough plate: used to detect airborne microorganisms, showing growth of microorganisms present in the air
Air plate: used to detect airborne microorganisms, showing growth of microorganisms present in the air

Alpha hemolysis: partial breakdown of red blood cells, resulting in a greenish zone around the bacterial colony
Beta hemolysis: complete breakdown of red blood cells, resulting in a clear zone around the bacterial colony
Gamma hemolysis: no breakdown of red blood cells, resulting in no visible zone around the bacterial colony

Good quality smear:
- Uniformly spread and dried
- Cells spread evenly and not overlapping
Basic stains:
- Positively charged, binding to negatively charged cell components
- Examples: methylene blue, crystal violet
Acidic stains:
- Negatively charged, binding to positively charged cell components
- Examples: fuchsin, eosin
Heat fixation:
- Used to fix cells to a slide, allowing them to adhere and not be washed away
- Unstained cells are:
  - Cells that have not been stained with a dye

Dimorphic:
- Fungi that can exist in two different forms (e.g. yeast and mold)
- Examples: Candida, Histoplasma
Hyphae:
- Long, branching filaments that make up the mycelium
Mycelium:
- A mass of hyphae
Reproduction:
- Fungi can reproduce by producing spores or by fragmentation

Durham tubes:
- Used to detect gas production in microbial cultures
- Contain a small inverted tube that traps any gas produced

Phenol red:
- A pH indicator used to detect changes in pH due to microbial metabolism
- Turns yellow in acidic conditions and pink in basic conditions

Sugars tested:
- Glucose, lactose, etc.
Homolactic fermentation:
- Fermentation that produces only lactic acid as a product
- Examples: Lactobacillus
Heterolactic fermentation:
- Fermentation that produces a mixture of products, including lactic acid, ethanol, and carbon dioxide
- Examples: Leuconostoc