LO 2 Flashcards
(99 cards)
Define: Normal Flora
Microorganisms growing in or on the body all the time without causing injury to the host
- They permanently reside on our bodies and do not produce disease under normal circumstances
Define: Pathogenic
Capable of causing disease
What is the composition of normal flora?
Fairly constant for a given site; but varies depending on the site ( ex. the flora in the mouth is different then normal flora of the intestine or skin)
Which area of the body has the greatest amount of normal flora?
The large intestine has the greatest normal flora population
Define: Escherichia coli (E.coli) and where is it located?
E. coli is a rod-shaped bacterium (Bacilli- gram negative) found in the feces
Normal intestinal flora plays an important role in what?
Food digestion and evacuation of feces
What type of bacteria(normal flora) is found in mucous membrane of the upper respiratory tract? And what is their role?
Streptococci of the viridans group. They occupy attachment sites on host cells and prevent pathogenic bacteria from invading the respiratory tissue
What type of normal flora bacteria is found on the skin?
Staphylococci. (Live on a cool, dry, salty surface) Main normal flora on the skin. It is gram positive & blue
What are the two factors that affect Normal Flora? How?
1) Excess moisture on the skin = increase in staphylococci on skin
2) Antibiotic use = alters normal flora as the sensitive bacteria are killed allowing more resistant strains to predominate
Define: Contamination
Microorganisms present on the body (on a site where they are not expected) but they are not growing or causing damage to the host
- ex. saliva on skin
Define: Colonization
Microorganisms present and growing in or on the body but without causing any damage to the host
Define: Disease
Microbes multiplying in the host and causing damage to the host (it is evident and measurable)
Define: Infection
Often used to mean the same as disease (Microbes multiplying in the host and causing damage to the host) but also used to indicate growth of microbes in the host before disease symptoms become evident.
- Has been invaded with a pathogenic organism but there are no signs of lasting host damage
HIV/ AIDS infection or disease?
A person may be infected with HIV but show no signs of injury for some time. Once the symptoms of AIDS becomes evident, the host is described as having the disease AIDS
The lining of the urinary bladder is normally sterile. Bacteria will occasionally grow on the bladder mucosa without causing any disease or harm to the host. The term covering this relationship is ________
Colonization
The bacteria causing tuberculosis multiply inside white blood cells of the body for several weeks without causing any injury to the host. The person is described as being ____ with tubercle bacilli. Several weeks later symptoms of tuberculosis become evident and the person is said to now have the ______
The bacteria causing tuberculosis multiply inside white blood cells of the body for several weeks without causing any injury to the host. The person is described as being infected with tubercle bacilli. Several weeks later symptoms of tuberculosis become evident and the person is said to now have the disease
Throat cultures of most individuals with no evidence of sore throats will show viridans _____. These streptococci are ______.
Throat cultures of most individuals with no evidence of sore throats will show viridans streptococci. These streptococci are normal flora.
Staphylococcus aureus growing in a surgical incision causing swelling and inflammation would be described as ______
Staphylococcus aureus growing in a surgical incision causing swelling and inflammation would be described as infection.
Fecal bacteria on the hands of a person visiting the bathroom and failing to wash their hands after this visit would be called ______ as long as the bacteria were not growing and injuring the host
Fecal bacteria on the hands of a person visiting the bathroom and failing to wash their hands after this visit would be called contamination as long as the bacteria were not growing and injuring the host
Define: Pathogen
A disease-causing organism
Define: Virulence
The degree of pathogenicity
What are the factors of virulence? (4)
1) Enzymes that dissolve hyaluronic acid (tissue cement), collagen and fibrin clots, allowing bacteria to spread faster in the tissue
2) Substances that destroy RBC, releasing iron necessary for bacterial growth
3) Substances that destroy WBC, weakening the body defence
4) Capsules, or slimy coatings, which prevent attachment of phagocytic (eating) white blood cells
Define: Non-pathogen
An organism unable to cause disease
* Most common type of bacteria
Define: Low grade pathogen or opportunistic pathogens
They are non-pathogenic under most condition but may cause disease when the host’s defenses are lowered by predisposition conditions
- Only causing disease when the host defenses are lowered
- Only become bad when they have the opportunity to