What is a microorganism?
- organism too small to be seen without the aid of a microscope
- Relatively simple in structure and often unicellular
- “microbe” “germ” or “bug”
What are the four groups of microorganisms?
- Protozoa
- Fungi
- Bacteria
- Viruses
What are protozoa?
- Unicellular creatures that are able to move either by flagella or amoeboid motion
- Each cell has a nucleus and is enclosed by a plasma membrane
Where do protozoa live?
- Water and soil and feed on bacteria and small particles
- Some live in our bodies without causing any harm but few are responsible for disease
What causes beaver fever?
The protozoa giardia.
How does Giardia affect humans?
Attaches to the intestinal wall by two sucking discs resulting in diarrhea because the food cannot be broken down and absorbed properly.
How does Giardia move?
Flagella
Some amoebas will also invade what?
- The intestinal wall and cause diarrhea
- They will occasionally move into deeper tissue
Where are Amoebas usually picked up?
- warm countries with poor sanitation
- May move by extension of pseudopods and do not have flagella
What are fungi?
- Non photosynthetic plants
- Each cell has a nucleus and is enclosed by a rigid cell wall.
How can fungi be divided into?
Yeasts and molds
What are yeasts?
- Unicellular oval structures that reproduce by budding
- Used in food and beverage
- Look the same under the microscope
Are yeasts capable of causing disease?
Yes some yeasts are capable
Which yeast is the most commonly involved in disease in humans?
Candida
What are symptoms of Candida?
- Cause oral thrush
- Vaginal discharge
- Skin infections
- Pneumonia
- Death possible
What are molds?
- Multicellular structures that form visible clumps of growth
- Starts out with long tubular structures that eventually produce spores which are visible as grey, blue - green or black growth
What are bacteria?
- Tiny unicellular organisms typically surrounded by a rigid wall
- Do not have organized nucleus but carry out all of the activities necessary for growth and reproduction
Bacteria are ubiquitous, what does this mean?
- They are found just about everywhere there is moisture and nutrients.
- Many bacteria grow in or on humans and are an essential part of our body flora, many other cause infection
What is an example of bacteria disease?
- Strep throat which is caused by a bacteria called streptococcus
- Food poisoning caused by salmonella from poultry
What are viruses?
Smaller than bacterial and have simple structure
Can Viruses grow by themselves?
No, they must rely on a living host cell to replicate the viral parts
How do we treat for protozoal infections?
Antiprotozoal drugs
How do we treat for fungal infections?
Antifungal meds
How do we treat for bacterial infections?
Antibiotics
