Definitions (Dustin) Flashcards

(57 cards)

1
Q

Transport Medium

A

medium for transporting clinical specimens to the lab for examination. Able to keep the organism for 48 hours

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2
Q

Pathogenicity

A

Ability of a microbe to cause disease in the host

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3
Q

Virulence

A

Degree of damage caused by pathogen. Objective, quantitative measurement of pathogenicity. Can be measured by LD50 titer.

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4
Q

Endotoxin

A

Generally refers to phospholipid-polysaccaride components of cell wall in gram negative bacteria. Lipid-A of LPS -> endotoxin. Generally more heat stable, less specific, and less potent than exotoxins.

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5
Q

Active immunization

A

Giving live or killed infection agents or their antigens -> host actively produces antibodies, lymph cells able to respond to antigen

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6
Q

Passive immunization

A

Giving ready-made antibodies, for example when the patient is already ill.

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7
Q

Agglutination

A

Antigen-antibody rxn ends up in visible sedimentation of Ag-Ab complex. May be used in serotyping.

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8
Q

Antibody titer

A

Lowest concentration (highest rate of dilution) of antibodies at which the given rxn still gives a visible result

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9
Q

Resident vs transient microbial flora

A

pretty self explanatory. transient are only there temporarily

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10
Q

Vaccine

A

Any preparation used for active immunological preventive treatment. Often from killed or attenuated microbes of virulent strains

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11
Q

Toxoid

A

An exotoxin detoxicated by heat or formaldehyde. Can provoke an immuno response, but it’s non-toxic. E.g. the vaccine for diptheria and tetanus

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12
Q

Attenuation

A

Selecting mutant, not virulent strains of a microbe. These are alive, but harmless microbes. Can provoke immuno response, so can be used for vaccination. E.g. BCG vaccine contains attenuated mycobacterium bovis (for tuberculosis)

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13
Q

Agglutinin

A

An antibody that causes clumping or agglutination of bacteria or other cells

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14
Q

Co-agglutination

A

A passive agglutination test in which specific antibody is in vitro bound to surface of S. aureus cells. The bound antibodies cause agglutination if the homolog antigen is added. The antibodies (or antigens) can be bound to latex instead, then it’s latex agglutination.

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15
Q

Precipitin

A

An antibody that under suitable conditions crosslinks with its specific, soluble antigen and causes precipitation

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16
Q

O antigen

A

Somatic antigen of enteric gram-negative bacteria. External part of cell wall liposaccharide

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17
Q

H antigen

A

flagella. highly antigenic part of enteric gram-neg bacteria

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18
Q

Capsule Antigen

A

capusle of bacteria is highly antigenic. In enteric bacteria it is called the K antigen

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19
Q

Protective antigen

A

Antigen responsible for protective immunity, so we can use it for vaccination

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20
Q

Bacteriolysis

A

Dissolution of bacteria. For example, using hypotonic solution or a specific antibody and complement that destroys the bacterial membrane

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21
Q

Epidemy

A

Infections occuring as part of an outbreak of infection. Defined as a significant increase in the usual rate of infection.

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22
Q

Endemy

A

A disease which happens in relatively low numbers, but continuously in a specific community.

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23
Q

Pandemy

A

Worldwide epidemy

24
Q

Vector (2 definitions)

A
  1. An invertebrate animal (i.e. tick, mite, mosquito) capable of transmitting an infectious agent among vertebrates.
  2. DNA that automatically replicates in a cell to which another DNA segment may be inserted and itself replicated, as in cloning
25
Antibacterial resistance
The ability of a microorganism to survive and multiply in the presence of antibiotics. Usually carried on bacterial plasmids
26
Polyresistance
A microorgamism showing resistance to many groups of antibiotics
27
Cross resistance
when resistance to one antibiotic means resistance to a second with a similar mode of action as the first
28
Bactericidal Effect
the ability of a substance to kill bacteria
29
Bacteriostatic effect
the ability of a substance to inhibit the growth of bacteria
30
Selective toxicity
an antibacterial agent kills only the bacteria, leaving the host unharmed (totally or relatively)
31
Minimal Inhibitory Concentration (MIC)
the lowest concentration of antibiotic sufficient to inhibit bacterial growth and proliferation when tested in vitro
32
Minimal Bactericidal Concentration (MBC)
the lowest concentration of antibiotic that kills bacteria (different for different strains)
33
Chemotherapeutic Index
lowest dose toxic to patient divided by dose typically | used for therapy. (DTM/DCM) The higher the index, the more effective chemotherapeutic agent
34
Antibiogram
A record of the resistance of microbes to various antibiotics, which is result of susceptibility testing (determination of the ability of an antibiotic to kill or inhibit the growth of bacteria)
35
Aerobic bacteria
A bacterium that uses oxygen, and is capable of living and surviving in the open air
36
Obligate Anaerobic Bacteria
An anaerobic bacterium that will grow only in the | absence of free oxygen, and is not able to survive in the presence of oxygen
37
Facultative Anaerobic Bacteria
an anaerobic bacterium, which grows in the presence of air, but can also survive under conditions of reduced oxygen
38
Microaerophilic Bacteria
An aerobic bacterium that requires oxygen, but less than is | present in the air, and grows best under modified atmospheric conditions
39
Differential Media
a medium that will cause the colonies of a particular type of organism to have a distinctive appearance. E.g. EMB (Eosin Methylene Blue) medium is used to distinguish between lactose-fermenting (purple colonies) and non-fermenting (colorless colonies) gram-negative bacteria.
40
Selective Media
A culture medium containing ingredients that inhibit growth of any microorganism other beside the desired one. E.g. EMB is not only differential but also selective medium, because it inhibits the growth of gram-positive bacteria, only gram-negative bacteria will appear on that.
41
Obligate Pathogenic Bacteria
bacterium that is pathological whenever present
42
Facultative Pathogenic Bacteria
a bacterium that may causes illness, not in all cases, just under special circumstances (e.g. normal flora of our body, as E.coli)
43
Ubiquitous Bacteria
bacteria that lives in our environments.
44
Autotrophic Bacteria
a bacterium that produces food for itself from inorganic compounds.
45
Heterotrophic Bacteria
a bacterium that produces food for itself from organic | compounds.
46
Paratrophic Bacteria
a bacterium that is obligate intracellular parasite, and is able live only in an eukaryote cell (therefore we are not able to cultivate them in vitro) E.g. rickettsiae
47
Parasitism
a relationship between the host and the microbe, when the presence of the microbe is harmful for the host
48
LD50 Definition
Lethal Dose 50% or Median Lethal Dose: the dose likely to cause death of 50% of the test animals The LD is dependent on the kind of the organism. (LD100:absolute lethal dose, is the dose that kills all of the test animals or bacteria)
49
Zoonosis
an infection or parasite shared in nature by humans and other animals that are normal or usual host, the disease of humans is acquired from an animal source.
50
Bacterium Strain
a population of bacteria originated from one colony maintained for a long time during laboratory condition with constant genetic properties
51
Bacterial Isolate
a population of bacteria that belong to one species and was isolated at a certain time from a certain origin
52
Primary Immune Response
the response of the immune system to a first encounter with an antigen, which leads to the condition of induced sensitivity. The primary immune response is detectable, as a rule, only after a lag period. IgM is the main immunoglobulin produced early in the primary immune response, followed by IgG, IgA or both. The serum antibody concentration continues to rise for several weeks and then declines, the IgM levels sooner than the IgG.
53
Secondary Immune Response
The immune response to a second encounter with an antigen. The secondary response is much faster than in case of the primary immune response, because of the persistence of antigen-sensitive memory-cells remaining from the first immune response. IgG is the predominant immunoglobulin in secondary responses, and its level tends to persist much longer than in the primary response.
54
Sterilization
The total destruction of all microbes. That can be accomplished using physical, gas vapour or chemical sterilants.
55
Parameters of Autoclaving and Circulating Hot Air Sterilization
Hot Air: normal pressure 140 C – 3 hours / 160 C – 2 hours / 180 C – 1 hour Autoclave: + 1 atm pressure 121 C – 30 min Flash Autoclave: + 2 atm pressure 134 C – 3 min
56
Disinfection
treatment which reduces the number of potentially pathogenic microorganism in an environment (does not destroy all microbes)
57
Ribotype
the typing of bacteria, based on the 16s subunit of the ribosome