Exam 1 Flashcards
What is symbiosis?
Neutral, antagoistis or synergistic relationship between 2 dissimular organisms (symbiotes/symbionts) living in close association with each other.
What is Mutualism?
Mutually beneficial relationship between two species.
What is commensalism?
Relationship between 2 species where one benefits and the other is not affected.
What is parasitism?
Relationship between 2 species where one benefits (parasite) from the other (host); usually detrimites the host but not always
Where is the highest amount of resident microbes?
The large intestine.
What/where is the resident flora of the skin?
Where=the epidermis
What=mostly staphylococcus
What/where is the resident flora of the oral cavity?
Where=cheeks, gum, teeth
What=streptococcus species
What/where is the resident flora of the stomach and intestine?
- gastric Helicobacter pylori
- L. intestine mostly anaerobic microbes
- microbes like E. coli and Lactobacillus
What is the resident flora of the upper respiratory tract?
- streptococcus and staphylococcus
- lower respiratory tract should be sterile
Whats is the resident flora of the genital tract?
- vaginal flora is influenced by hormones
- change in flora after puberty
- Lactobacillus
What is the resident flora of the urethra?
Many opportunitic microbes
What are the 4 roles of normal flora?
- Common source of infection
- Immune stimulation
- Keep out invadors
- Nutrition and metabolism
What are the 4 factors controlling the growth of microorganisms?
- Nutrient availability
- Environment
- Competition
- Host immune system
What is a fastidious organism?
An organism that has complex nutritional or cultural requirments, making isolation and culture more difficult.
What parameters are involved in the environment?
- Water activity (osmotic pressure)
- Oxygen requirements
- pH of the environment
- temperature
How is an infectious agent accquired?
- Enters the host
- Colonization
- Invasion
- Multiplication
What are some entries/exits?
- Ingestion
- Inhalation
- direct penetration
What does colonization mean?
Successful occupation of a new habitat by a species not normal found in that niche.
What does adherence mean?
Close association of bacterial cells and host cells generally characterized by receptors on target sites.
What is adhesin?
Structure or macromolecule located on the surface of a cell that facilitates adherence of a cell to a surface or to another cell.
What does invasion mean?
Entry and spread throughout cells and/or tissues of the host. (specific recognition of receptor sites on target cells enhances pathogenic advantage)
What are invasins (invasive factors)?
Structures or macromoles that facilitate invasion by a pathogenic microoganism.
What does multiplication mean?
The ability of a microorganism to reproduce during an infection; influenced by underlying disease, immunologic status, antibiotic treatment, nutrient availability
What is a vector?
A carrier; the animal that transfers an ifectious agent from one host to another, usually an arthropod.





