Midterm 1 Terms and Definitions Flashcards
Transport medium
for transporting clinical specimens from patients to lab.
Sufficient to survive for 24-48 hours but not for them to replicate significantly or a single pathogen to overgrow others present.
Pathogenicity
Qualitative, can the microbe cause disease
Virulence
Quantitative, How much pathology does a given amount of the pathogen cause?
What is the LD50, expressed as a virus titer.
Heterophil antigen
An antigen that is found on many unrelated species
An Exotoxin
A specific, soluble, antigenic, injurious substance produced and secreted by bacteria.
Usually heat labile, most are proteins.
A Toxoid
A non-toxic but antigenic portion or form of an exotoxin produced by bacteria,
A heat/chemically detoxified form of an exotoxin that can be used for vaccines.
An Endotoxin
The phospholipid-polysaccharide macromolecules that are integral bacterial cell wall components in Gram Negative bacteria.
The Lipid-A portion of LPS is responsible for endotoxin toxicity.
Less potent than exotoxins, and are relatively heat stable.
Active vs passive immunization
Active: a vaccine, produces memory cells
Passive: administering antibodies, does not produce memory cells.
Agglutination
Antigen-antibody reaction that causes visible sedimentation of large complexes.
Antibody titer
the lowest concentration of antibodies which still give a visible result in the reaction, Elisa, complement fixation, agglutination.
Attenuated vaccines
Vaccines in which the bacteria/microbes are not killed or completely destroyed, but rather their virulence is just reduced somehow, and still alive yet harmless microbes are used in the vaccine.
An Agglutinin
An antibody that causes agglutination of the bacteria or target cells
Co-agglutination
An agglutination test using antibodies bout to S. Aureus cells, which will then agglutinate in the presence of the target antigen for htose antibodies.
Precipitin
An antibody that precipitates from solution when binding its target antigen
O-antigen
The external 40 repeated tetrasaccharide portion of LPS in gram negative cell walls
Somatic antigen
A somatic antigen is an antigen located in the cell wall of a gram-positive or gram-negative bacterium.
H-antigen
The flagella of enteric gram-negative bacteria.
H from the German word for ‘film’ no longer sensible
Capsule antigen
The capsule of bacteria, called K-antigen for enteric bacteria
Protective antigen
An antigen responsible for generative protective immunity,
ie an antigen used in vaccines.
Epidemy
An epidemic disease, an outbreak of high numbers
Endemy
A disease that occurs constantly in low/regular numbers
Pandemy
worldwide epidemic
Vector
Either:
1) An invertebrate animal that transmits infections agents to vertebrates
2) DNA that automatically replicates in a cell, which can have other DNA segments inserted into it. ex. plasmids, viral vectors , artificial chromosomes.
Selective toxicity
An antibacterial agent which kills only the bacteria leaving host unharmed.
