Pathogenesis Of Microbes Flashcards
Infection:
____________ of an infectious agent within the body.
Multiplication
Multiplication of the bacteria that are part of normal flora of gastrointestinal tract, skin, etc, is generally considered an infection.
T/F
F
Not
On the other hand, multiplication of pathogenic bacteria (e.g. Salmonella species), even if the person is _______, is deemed an infection.
T/F
asymptomatic
T
Pathogenicity:
The ability of an infectious agent to __________
cause disease.
Virulence:
The ______ of an agent to _______
quantitative ability
cause disease.
Virulent agents cause disease when introduced into the host in (small or large ?) numbers.
Small
Virulence involves _________ and _________
invasiveness and toxigenicity.
Toxigenicity:
The ability of a microorganism to ______________
produce a toxin that
contributes to the development of disease.
Invasion:
The process whereby bacteria, parasites, fungi and viruses ———————
enter the host cells or tissues and spread in the body.
Pathogen is A microorganism capable of causing disease.
T/F
T
Non-pathogen is A microorganism that does not cause disease. It may be part of the normal flora.
T/F
T
Opportunistic pathogen:
An agent capable of causing disease only when _______________
An agent capable of causing disease only when spread from the site with __________________ to the _________
the host ́s resistance is impaired (e.g. the patient is immunocompromised).
normal bacterial microflora
sterile tissue or organ.
The pathogenesis of bacterial infection includes the _____ of the infectious process and the mechanisms leading to the development of signs and symptoms of bacterial disease.
The outcome of the interaction between bacteria and host is determined by characteristics that favour establishment of the bacteria within the host and their ability to damage the host as they are opposed by host defense mechanisms.
initiation
Oubreak - ______
Epidemic - _______
Pandemic – _________
local
regional/national
widespread (international)
Most bacteria do not produce disease but ____________________ that ensures the survival, growth, and propagation of both the bacteria and the host.
achieve a balance with the host
Most bacteria produce disease
T/F
F
Sometimes bacteria that are clearly pathogens (e.g. Salmonella typhi) are present, but infection remains ____ or ______ and the host is a “ ______ “ of the bacteria.
latent
subclinical
carrier
In 1884, Robert Koch proposed a series of postulates in his treatise on ______ as _______
Mycobacterium tuberculosis and tuberculosis.
Koch ́s postulates are summarized as follows:
The microorganism should be _______of the disease in question, and its distribution in the body should be in accordancce with the _______ observed.
The microorganism should be grown in ______________ for several ______.
When such a pure culture is __________, the ________ must result.
The microorganism must again be ___________
found in all cases ; lesions
pure culture in vitro;23
inoculated into susceptible animal species; typical disease
isolated from the lesions of such experimentally produced disease.
Koch ́s postulates remain a mainstay of microbiology.
T/F
T
However, since the late 19th century, many microorganisms that do not meet the criteria of the postulates have been shown to cause disease. For example, Treponema pallidum (____) and Mycobacerium leprae (____) cannot be ______, but there are _________
syphilis; leprosy
grown in vitro
animal models of infection with these agents.
In another example, Neisseria gonorrhoeae (gonorrhea), there is no __________ even though the bacteria can readily be ________
animal model of infection
cultivated in vitro.
The __________ should be considered when an organism is being investigated as the possible cause of a disease.
host ́s immune responses
