The idea that communicable diseases were caused by the passage of living things from one person to another was first put forth by
The microorganisms that are regularly found in or on the body, yet do no apparent harm are called
Organisms that are found together and interact on a more or less permanent basis are in a relationship termed
Which of the following is true about the role normal flora play in maintaining host health?
THEY PROVIDE A SURFACE THAT IS INCOMPATIBLE FOR ATTACHMENT OF AN INVADER, THEY ESTABLISH COMPETITION FOR NUTRIENTS AND VITAMINS, THEY PRODUCE ANTIMICROBIAL SUBSTANCES, AND THEY STIMULATE THE IMMUNE SYSTEM
Which of the following members of the normal flora inhibits the growth of Corynebacterium diphtheriae by producing hydrogen peroxide?
Which of the following members of the normal flora inhibits the growth of bacteria by production of fatty acids from lipids?
Staphylococcus epidermidis AND Propionibacterium species.
Which of the following may inhibit the activity of normal flora and allow pathogens to become established?
A diet high in meat leads to a population of normal flora with an increased number of
A member of the normal flora that becomes an opportunist if it invades the urinary bladder is
Which of the following may be considered virulence factors?
ADHESINS, CAPSULES, ENDOTOXINS AND PROTEASES
People who carry and may spread pathogenic organisms without any overt symptoms of illness are called
If a disease affects only a human and not an animal, then it would be difficult to fulfill Koch's postulate number
Transmission of an infectious disease by touching, handshaking, or kissing is considered
The portal of entry
plays a role in whether an infection will be established, may be the skin or respiratory tract AND may be the same as the portal of exit.
Which of the following factors is not considered important for the establishment of an infection?
The lack of susceptibility to diseases of other species in humans may be due to the
lack of receptors that are recognized by adherence factors.
Bacteria may survive phagocytosis by
preventing fusion of the lysosome with the phagosome AND preventing acidification of the phagolysosome.
Which is true about superantigens?
They are a type of exotoxin AND They bind to MHC class II antigen on T cells.
Which is/are true of viruses?
They may suppress the production of MHC Class I protein, They may produce an MHC Class I mimic protein AND They may prevent cell suicide.
Which is true about botox?
It may cause botulism AND It is useful in treating conditions related to muscle contractions.
In Gram-negative bacteria many of the genes required for pathogenicity are
located close together on chromosomes in regions called pathogenicity islands.
High concentrations of some bacteria are necessary for successful invasion because only at high density are their virulence genes expressed.
What reason could there be for some people to doubt that HIV is the causative agent of AIDS?
Koch's postulates have been used to make a connection between particular organisms and specific diseases. However, there are limitations to the use of the postulates. Koch's postulate #3 requires innoculating the host with the potential pathogen. Obviously, this is not possible for diseases only found in humans. This barrier may sometimes be circumvented if there is a good animal model. There is no real good animal model for AIDS. With no good animal model, it is not possible to make the direct connection between organism and disease, and one has to rely on indirect connections.