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.
MIC
Minimal Inhibitory Concentration:
lowest concentration that inhibits proliferation in vitro.
MBC
Minimal Bactericidal Concentration
lowest conc that kills bacteria in vitro
Chemotherapeutic Index
Dosis curativa minima / Dosis Tolerata maxima
Min effective dose / Max tolerated dose
Min effective dose / Max dose without toxicity.
Antibiogram
A record of the resistance of microbes to antibiotics.
Facultative Anaerobic bacteria
An organism that makes ATP by aerobic respiration if oxygen is present, but is capable of switching to fermentation or anaerobic respiration if oxygen is absent
Obligate Anaerobe
An organism that will not survive in the presence of oxygen
Microaerophilic Bacteria
an aerobic bacteria that requires oxygen, but at lower concentrations that in normal atmosphere.
Grows best in low (but present) oxygen in air.
Differential Media
A medium that causes different types of bacteria to have different appearances (colors)
Ie medium that distinguishes between fermenting (purple colored) and non-fermenting colonies (clear)
Selective Media
Media that has ingredients that inhibit growth of any microorganism besides the desired one.
Obligate pathogenic bacteria
Always pathogenic
Facultative pathogenic bacteria
May cause illness under special circumstances but not always
ex. E. coli in our gut.
Autotrophic Bacteria
produces energy from inorganic compounds
Heterotrophic Bacteria
produces energy from organic compounds
Paratrophic Bacteria
Obligate intracellular parasites.
Only able to live inside a eukaryotic cell.
Absolute lethal dose
LD100.
The dose that kills 100% of the experimental animals
Zoonosis
An infection or parasite that both humans and other animals may get.
Disease acquired in humans from an animal host
Bacterial isolate
a population of bacteria from one species that was isolated from a specific place and time
Bacterial strain
A population of bacteria isolated from a single colony maintained in a lab for a long time.
Primary immune response
The response to the very first encounter with an antigen.
As a rule is only detectable after a lag period.
IgM the main ab produced early in the response
Then IgG, or IgA, or both.
Serum ab levels rise for a few weeks then decline. IgM levels decline first.
Secondary immune response
The response to the second encounter with an antigen.
Faster than the primary response, higher in magnitude, and longer lasting
IgG is the main ab produced in the secondary repsonse.
Sterilization
the complete killing of all microbes
Disinfection
reduces the number of microbes
Ribotype
Bacteria classified based on the 16S subunit of the ribosomes
