Lecture 4 Flashcards
HD
Opportunists are microorganisms that
cause disease when the proper condition arises.
A species of bacterium lives on the surface of the human skin. It does not help or harm the human host. However, it gains a habitat. This symbiotic relationship is
commensalism
By microbial antagonism, one microbe
inhibits the growth of another microbe.
Through opportunism among microbes, commensals change to
pathogens.
Pathology is the study of
disease
Etiology
the study of the cause of the disease
Pathogenesis is
The development of disease
Infection
Invasion and Colonization of the body by pathogens
Disease
When infection results in change of a state of health (sometimes with no symptoms).
What is Lactobacillus acidophilus
Acid tolerant bacteria
Transient microbiota maybe present for how long
Days weeks or months
Normal microbiota and the host- what does normal microbiota do to the host
Permanently colonize the host
What is the relationship between normal microbiota and the host
Symbiosis
Mutualism
Both organisms benefit
Parasitism
One organism is benefited at the expense of the other
Probiotics
Are live microbes applied to or ingested into the body, intended to exert a beneficial effect
What are 3 things that normal microbiota do to protect the host?
Occupy niches that pathogens might occupy
Produce acids
Produce bacteriocins
Koch’s postulates are used to prove…
The cause of an infectious disease
Communicable disease
A disease that is spread from one host to another
Contagious disease
A disease that is easily spread from one host to another
Noncommunicable disease
A disease that is not transmitted from one host to another
Endemic disease
Disease constantly present in a population
Epidemic disease
Disease acquired by many hosts in a given area in a short time
Pandemic disease
Worldwide epidemic
Heard immunity
Immunity in most of a population
Bacteremia
Bacteria in the blood
Septicemia
Growth of bacteria in the blood
Toxemia
Toxins in the blood
Direct Contact - definition and examples
Requires close association between infected and susceptible host. (eg: Rabies, rat bite fever, STD)
Indirect contact - definition and examples
Spread by fomites (inanimate objects) (e.g. Gas Gangrene)
Droplet contact - definition and examples
Transmission via airborne droplets ( e.g. influenza virus, Tuberculosis)
What are 3 types of Vehicle transmission
- Water Borne
- Airborne
- Food-Borne
What are 4 types of person to person transmission
- Blood-borne (HIV)
- Genital Tract (Herpes)
- Eye to Eye (Chlamydia)
4.Urinary Tract Nosocomial (Catheter Use)
2 types of Vector transmission
Mechanical and Biological
2 x Examples of Biological transfer
Lyme disease and Malaria (Ticks and Mosquitos)
2 x examples of Mechanical transfer
E.coli and Samonellosis (Flies)
What is a nosocomial infection
Are acquired as a result of a hospital stay
botulism tetanus come from what nonliving transmission reservoir
soil
The major significance of Koch’s work was that
Microorganisms cause disease.
Koch’s postulates don’t apply to all diseases because
Not all diseases are caused by microorganisms
Which of the following diseases is NOT spread by droplet infection?
A) Botulism B) Tuberculosis C) Measles D) Common cold E) Diphtheria
Botulism
Mechanical transmission differs from biological transmission in that mechanical transmission
A) Doesn’t require an arthropod. B) Involves fomites. C) Doesn’t involve specific diseases.
D) Requires direct contact. E) Doesn’t work with noncommunicable diseases.
Doesn’t involve specific diseases.
A cold is an example of what kind of occurence A) endemic B) epidemic c) pandemic d) sporatic e) incidence
Endemic
Transient microbiota differ from normal microbiota because transient microbiota
A) Cause diseases. B) Are found in a certain location on the host.
C) Are acquired by direct contact. D) Are present for a relatively short time. E) Never cause disease.
Are present for a relatively short time
Which of the following is NOT a communicable disease?
A) Malaria B) AIDS C) Tuberculosis D) Tetanus E) Typhoid fever
D) Tetanus
Which of the following is NOT a reservoir of infection?A) A sick personB) A healthy personC) A sick animalD) A hospitalE) All of the above can be reservoirs of infection.
E) All of the above can be reservoirs of infection.
What are fomites?
Objects or materials which are likely to carry infection, such as clothes, utensils, and furniture.
Influenza transmitted by an unprotected sneeze is an example of
A) Direct contact. B) Droplet transmission. C) Fomite. D) Vector. E) Vehicle transmission.
B) Droplet transmission
A sexually transmitted disease is an example of
A) Direct contact. B) Droplet transmission. C) Fomite. D) Vector. E) Vehicle transmission.
A) Direct contact
Gastroenteritis acquired from roast beef is an example of
A) Direct contact. B) Droplet transmission. C) Fomite. D) Vector. E) Vehicle transmission
E) Vehicle transmission
A needlestick is an example of
A) Direct contact. B) Droplet transmission. C) Fomite. D) Vector. E) Vehicle transmission
C) Fomite
Pseudomonas bacteria colonized the bile duct of a patient following his liver transplant surgery. This is an example of a
A) Communicable disease. B) Latent infection. C) Nosocomial infection.
D) Sporadic disease. E) None of the above.
C) Nosocomial infection.
Legionellosis transmitted by a grocery store mist machine is an example of A) Direct contact. B) Droplet transmission.C) Fomite.D) Vector.E) Vehicle transmission.
E) Vehicle transmission.
Plague transmitted by a flea is an example of
A) Direct contact. B) Droplet transmission. C) Fomite. D) Vector. E) Vehicle transmission.
D) Vector.
The most likely mode of transmission of pneumonic plague between humans is
A) Direct contact.B) Droplet transmission.C) Fomite.D) Vector. E) Vehicle transmission.
B) Droplet transmission.
Proteinaceous or Peptidic toxins produced by bacteria to inhibit the growth of similar or closely related bacterial strain
What are Bacteriocina?
Sporadic disease is when disease….
occurs infrequently and irregularly
What is an Exogenous Infection
Organisms from any where outside to inside the body,
What is an Endogenous Infection
Direct implantation of bacteria into the wound
How does Bifidobacterium promote infant health?
by fermenting milk sugars to acetic and lactic acids- the acidic environment is in hospitable to many pathogens.
Microbes that establish a permanent /long lasting residence
Resident microbiota
Microbes that may be present for days, weeks and even months and then disappear
Transient microbiota
Example of Communicable diseases (Contagious diseases)
Chicken pox, measles, Genital herpes, Typhoid fever
Examples of Non-communicable diseases (diseases that are not contagious)
Tetanus
Disease that develops rapidly but lasts a short time
Acute disease
Develops slowly, but it lasts for a long time, e.g. tuberculosis, hepatitis B)
Chronic disease
Intermediate between acute and chronic, e.g. Pan-encephalitis of brain; loss of nervous function
Subacute disease
The causative agent remains inactive for a long period, e.g. Shingles caused by Varisella-zoster virus
Latent disease
True or False Pathogens need a reservoir?
True
Collection of data that describes the occurrence of a disease
Descriptive epidemiology
Begins with a hypothesis about a disease
Experimental Epidemiology
Analysis of a disease to determine it’s probable cause
Analytical epidemiology
True or False : Candida albicans can become an opportunist in the human body during antibiotic therapy.
True