Ch 13-15 Flashcards
What occurs during the contact process?
-not all contacts lead to colonization
What occurs during the infection process?
- a condition in which pathogenic microorganisms penetrate host defenses, enter the tissues and multiply.
- not all infections lead to disease
- contact to colonization to infection to disease
What occurs during the disease process?
-any deviation from health
-factors that cause disease: Infections,diet,genetics, and aging
Infectious disease: disruption of tissue or organs caused by microbes or their products
What terms are used to describe resident flora?
- indigenous biota
- normal flora
What types of organisms make up resident flora?
-array of bacteria, fungi, protozoa, and viruses
What is the name of the infection if arises from patients own microbes?
Endogenous Infection??
When and how is the newborn colonized with flora?
- doctors and scientists believe that fetuses are seeded when normal microbiota in utero
- exposure occurs during the birth process, when the baby becomes colonized with the mothers vaginal biota
- c-section babies are colonized by adult skin biota.
- -Contact with birth canal during birth
- Feeding
- Other human contact
- -8-12 hours after delivery
Where are resident flora located?
--large and diverse collection or microbes living on and in the body Most areas of the body in contact with the outside environment harbor resident microbes: -GI Tract Oral Cavity Lg. Intestine Rectum -Genital Tract -Upper Respiratory Tract -Skin -Urinary Tract -External Eye Lids & Lash Follicles -Ear External Ear & Canal
Where are resident flora not located?
Internal organs & tissues & fluids are microbe-free
- Lung
- Sinus
- Kidney
- Blood
- Fetus
What is microbial antagonism?
- The generally antagonistic effect good microbes have against intruder microorganisms
- microbes in a stead, established relationship are unlikely to be displaced by incoming microbes
What are opportunistic pathogens?
Causes disease
- when the host defenses are compromised
- when they become established in a part of the body that is not natural to them
How do opportunistic pathogens compare to true pathogens?
True Pathogens: Cause disease in healthy person with normal immune defense
Opportunistic Pathogens: Cause disease in immune comp’d. host and/or cause disease when access to sterile environment is gained
(endog. and exog.)
What type of factors weaken host defenses?
- Old age and extreme youth (infancy, prematurity)
- Genetic defects in immunity and acquired defects in immunity (AIDS)
- Surgery and organ transplants
- Organic disease: cancer, liver malfunction, diabetes
- Chemotherapy/immunosuppresive drugs
- Physical and mental stress
- Other infections
What are examples of virulence factors?
–traits used to invade and establish themselves in the host, also determine the degree of tissue damage that occurs- severity of disease
- People who are carriers of mutation in their hemoglobin gene, have few or no sickle-cell disease syndromes but are more resistant to malaria than people who have no mutations in their hemoglobin genes
- People of west African are more likely to have one or two sickle-cell alleles. Malaria is endemic in West Africa and it seems the hemoglobin mutation is adaptation of the human host to its long-standing relationship with the malaria protozoan.
- researchers have found a gene that correlates with how people react to infections with the swine flu virus. The gene codes for a protein that blocks viral entry into cells. People who have mid flu symptoms were found to have the gene, where those who become ill and died were likely to have a mutation of this gene.
What is TORCH?
TORCH is common infections of the fetus and neonate
T: Toxoplasmosis
O: Other Diseases- syphilis, coxsackievirus, varicella-zoster virus, AIDS, chlamydia
R: Rubella
C: Cytomegalovirus
H: Herpes simplex virus
What are exotoxins?
-secreted by a living bacterial cell to the infected tissues
What are characteristics of exotoxins?
- Toxicity: toxic in minute amounts
- Effects on the body: specific to a cell type(blood, liver, nerve) induced TNF production resulting in fever
- Chemical composition: small proteins
- Heat denaturation at 60 degrees Celsius: unstable
- Toxoid formation: can be converted to toxoid
- Immune response: stimulate antitoxins
- Fever stimulation: usually not
- Manner of release: secreted from the live cell
- Typical sources: a few gram-positive and negatives
How are exotoxins named?
A toxin molecule secreted by a living bacterial cell into the infect tissues
What is the function of kinase?
Enzyme that catalyzes the transfer of a phosphate group from ATP to an intracellular protein.
-break up blood clots, enabling bacteria to spread
What is the function of coagulase?
Aa bacterial enzyme that brings about the coagulation (blood clotting) of blood or plasma and is produced by disease-causing forms of staphylococcus.
What is the function of enterotoxins?
A toxin in or affecting the intestines, such as those causing food poisoning for cholera.
What is the function of hyaluronidase?
An enzyme that catalyzes the hydrolysis of hyaluronic acid
- found in human testes
- holds animal cells together
What is the function of hemolysin?
- a class of bacterial exotoxins
- disrupts the cell membrane of red blood cells
- damage causes the red blood cells to burst and release hemoglobin (hemolyze)
What is the function of mucinase?
Digests the protective coating on mucous membranes and is a factor in amoebic dysentery