Any organism that harbors anothers organism.
An organism capable of causing disease in hour.
An association between two (or more) species.
one organism (parasite) benefits from the relationship
both members of the association living together benefit from the relationship.
two species live together in a relationship such that one benefits the other neither benefits nor is harmed.
Micro organisms are present.
pathogenic microorganisms penetrate the host defense
when an infection alters or changes the state of health from the normal state.
the capacity to produce disease.
refers to the intensity of the diesease
the weakening of the disease-producing ability of the pathogen.
comprise microbes that are always present on or in the human body.
Microbes that can be present under certain environmental conditions in any of the locations where resident microflora are found.
Organisms that take advantage of particular opportunities to cause disease.
Conditions that create opportunities for opportunistic organisms include
- failure of the host's normal defenses.
- Introduction of the organism into unusual body sites.
- Disturbances in the normal microflora.
Normal microflora competeing with pathogenic organisms and in some instances actively combating their growth.
caused by infectious agents such as bacteria, viruses, fungi, protozoa, and helminths.
caused by any factor other than infectious organisms.
In any substance that is poisonous to other organisms.
spreading of exotoxins by blood from the site of infection.
Diseases that result form the ingestion of a toxin.
Soluble substances secreted into host tissues.
part of the cell wall and are released into host tissues - sometimes in large quantities - from Gram-neg bacteria, ofeten when the bacteria die or divide.
an association between two (or more) species. Living together encompasses a spectrum of relationships.
Recognize examples of each type of symbiosis
How do we become colonized with bacteria?
- Passage thru birth canal.
- contact with others.
- contact with feeding material.
- contact with instruments.
- during nursing.
location of Staphylococus epdiermidis
Location of Streptococcus mutans
Location of Streptococcus pneumoniae
Location of Neisseria meningitidis
Locaiton of Haemophilus influenzae
Location of Lactobacillus species
List Koch's Postulates
- Agent must be observed in every case of a disease.
- Isolate agent from a disease host and grow in pur culture.
- Agent from pure culture must cause same disease when inoculated into healthy host.
- Agent must be recoerd form the experimentally inoculated host and ID as being identical to the orginal microbe.
Why are they koch's postulates used?
to be satisfied in order to prove that a specific organsm is the caustice agent of a particular disease.
How many classifications of diseases
due to errors in genetic information (non-infectious cause)
are structural and functional defects present at birth (due to drugs, xray exposure)
are disorders that develop as aging occurs.
Nutritional Deficiency Diseases
lower resistance to infectious diseases and contribute to the severity of infections.
are due to excesses or dificiencies of hormones
Can be caused by a variety of factors (emotional, psychogenic or infection)
such as allergies, autoimmune diseases, and immunodeficienceies
involved abnormal cell growth that leads to benign or cancerous tumors.
- are caused by medical procedures and/or treatment.
- Surgical errors.
- nosocomial infections.
are diseases whose cause is unknown.
How are communicable diseases acquired?
- transmitted from host to host directly or indirectly.
- Direct contact.
- some infections are more easily spread than others.
How are Non-communicable diseases acquired?
- diseases that are not spread from one host to another.
- acquired from one's own flora (pneumonia).
- acquired form a non-living environmental reservior (tetanus).
- Food poisoning.
What are virulence factors?
structural or physiological characteristics that help organisms cause infection and disease.
How do bacteria adhere to other cells?
- critical point in production of disease.
- adhesins are proteins found on attachment pili (fimbriae) and capsules.
- Adhesins allow pathogen to bind to receptors on target cells.
List three exoenzymes
What are the functions of Streptokinase.
- dissolves blood clots.
- expedites invasion into tissues.
What are the functions of Coagulase
- triggers blood plasma clotting.
- allowing bacteria protection form immune defenses.
- (Staphylococcus aureus)
What are the functions of Hyaluronidase?
enzyme digests hyaluronic acid, a glue-like substance that helps hold the cells of certain tissues together. (streptococcus pyogenes)
List the classic stages of infection.
- 1. Incubation period.
- 2. Prodromal phase.
- 3. Invasive.
- 4. Decline.
- 5. Convalescence.
What happens to Incubation Period?
- Microbes don't instantly produce symptoms when they enter the body.
- There is a lag between infection and symptoms.
- How Long depends on the organism, the host's response, the infectous dose by what route the organisms entered the body.
What happens in the Prodromal Phase?
Patients feels well (may have mild symptoms) but may be infectious.
What happens in Invasive stage?
- Patient experiences typical signs and systems.
- Organism is multiplying becomes well established.
What happens in Decline Stage?
Symptoms begin to subside.
What happens in Convalescence Stage?
patient begins to heal may still be infectious to others.