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MICI module 1 > Exam 1 > Flashcards

Exam 1 Flashcards

1
Q

What organism caused the plague?

A

Yersinia pestis (gram negative rod)

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2
Q

Who is Leeuwenhoek?

A

Created the first microscope. Discovered “animalcules” or organisms.

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3
Q

Who is Jenner?

A

Used the first vaccine and began process to lead to the eradication of smallpox

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4
Q

Who is Pasteur?

A

Disproved the theory of spontaneous generation (organisms generated from rotting organic material). Created pasteurization

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5
Q

Who is Semmelweis?

A

Hungarian physician. Discovered that washing hands was crucial in preventing child bed fever and post op infections by studying midwives and doctors activities Before deliveries

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6
Q

Who is Lister?

A

First to use “antisepsis” to control surgical infections

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7
Q

Who is Lina Hesse?

A

First to use Agar (gelatin) to solidify growth material for bacteria

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8
Q

When was the golden age of microbiology?

A

1880-1900. First pathogens identified

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9
Q

Who discovered penicillin?

A

Flemming. Discovered a certain mold inhibiting the growth of other bacteria. This was penicillin.

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10
Q

What is Koch’s Postulates?

A

Establishes an organism is the cause of a disease.

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11
Q

What are the requirements for Koch’s postulates?

A
  1. The same organism must be found in all cases of a given disease
  2. Organism must be isolated and grown in pure culture (agar/broth)
  3. Organism from pure culture must reproduce the disease when inoculated into a healthy animal.
  4. Organism must then again be isolated from sick animal
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12
Q

Describe cocci bacteria

A

Round bacteria
Streptococci (strep= chain, cocci= round)
Staphylococci (staphylo= grapes, clusters)

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13
Q

Describe Bacilli organisms

A

Rod shaped.
Coccibacilli = very short rods
Vibrio = curved rods
Spirochaetes= spiral rods such as Lyme diseased

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14
Q

What are actinomycetes?

A

Filaments with branching

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15
Q

Examples of appendages in a cell

A

Flagella
Fimbriae
Pili

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16
Q

What is contained in cytoplasm?

A

Chromosomes, plasmids, ribosomes, inclusions

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17
Q

Describe flagella

A

Long, slender, whip like structures that promote bacteria movement. Can only be seen using special stains
Monotrichous - single flagella
Peritrichous - tufts or multiple flagelli

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18
Q

Describe Fimbrae

A

Appendage of a cell. Finger like and made of proteins. Enable bacteria to attach to substances

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19
Q

Describe pili

A

Appendage of cell. Act as a channel to transfer dna between cells

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20
Q

What is the capsule

A

Material secreted by bacteria that covers the exterior of the cell, often made of polysaccharide (sugar). More prominent in some cells than others

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21
Q

Describe cell wall

A

A strong layer made of peptidoglycan (proteins and sugar) that maintains shape and integrity of the cell. Principal target for antibiotic action and stains using gram stain in some organisms

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22
Q

Describe the peptidoglycan layer

A

Cross links horizontally and vertically. Made of polymerized NAG and NAM (sugars). Very strong lattice that protects the cell from environment

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23
Q

Describe gram positive organisms

A

Thick peptidoglycan layer and no outer membrane. Are stained by crystal violet

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24
Q

Describe gram negative organisms

A

Has an outer membrane and a thin peptidoglycan layer. Is not stained by crystal violet after alcohol/acetone is used to remove dye

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25
Q

Describe the gram stain

A

Crystal violet is used to dye all bacteria dark purple
Iodine acts as a mordant and fixes the crystal violet to the bacteria
Alcohol/acetone washes out the stain from gram NEGATIVE organisms
Safranin (newer step) acts as a counter stain. stains gram negative bacteria pink

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26
Q

What is the purpose of acid fast staining?

A

Some bacteria can not be stained by the gram stain due to lipids in the cell walls making the bacteria waxy (ex, tuberculosis). Can be stained using powerful and toxic red acid fast stain

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27
Q

Describe the process of acid fast staining

A
  • staining with strong red stain
  • washing out stain with mixture of acid and alcohol
  • counter staining blue or green
    Acid fast organisms are sometimes referred to as AFB (active fast bacilli)
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28
Q

What does a lipid bilayer in the cell wall do

A

Contains proteins that act as channels to control entry of substances in and out of the cell

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29
Q

In gram negative bacteria what does the cell membrane contain?

A

An endotoxin (LPS)

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30
Q

Describe Ribosomes

A

Made of RNA and protein, sure if protein production and a good target for antibiotics as cells can not survive without ribosomes

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31
Q

Describe bacterial chromosomes

A

A single long circular molecular of DNA that is not separated from cytoplasm

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32
Q

True or false bacteria are Prokaryotic?

A

True. Bacteria have no nucleus there for they are Prokaryotic

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33
Q

Describe plasmids

A

Small circular pieces of DNA that can be transferred between bacteria. May contain the genes for antibiotic resistance and producing different variants

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34
Q

What are inclusions?

A

Granules in the cytoplasm. May act as storage of various substances. Toxins molecules for storage and metabolism

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35
Q

Describe endospores

A

Dormant and very resilient. Develop in cytoplasm and send signals to create spores if it is sensed the environment is tough. Only formed by certain genera of bacteria. Germinate new cell when environment is favourable again
Ex. Cdiff cells

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36
Q

What are domains

A

How bacteria are organized. Lacking nuclei (prokaryotes) or not (eukaryotes)

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37
Q

What is the kingdom classification for Prokaryotic organisms

A

Monera

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38
Q

What are used in naming bacteria

A

Genus and species are used whenever we call a bacterium by its name
Ex. Staphylococcus (genus) aureus (species)

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39
Q

What classification is used

Most frequently in clinical practise

A

Family, genus, species

Ex. Escherichia (genus) Coli (species), a member of the Enterobacteriaceae family

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40
Q

What is Aerobic?

A

An organism that grows in air. Obligate aerobic if must have oxygen
Capnophilic if CO2 is needed

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41
Q

What is facultative anaerobe?

A

Grows in air, and can grow without oxygen

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42
Q

What is anaerobe?

A

Grows without oxygen. Most species find oxygen toxic as a result of struggling to deal with wastes product produced in oxygenated environments

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43
Q

What is microaerophilic?

A

Grows in low concentration of oxygen but not in its absence or in air. A specialized lab condition

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44
Q

requirements for bacterial growth?

A
  • carbon source
  • nitrogen source
  • essential nutrients (vitamins)
  • correct temp
  • right atmosphere
  • inorganic ions, iron
  • Ph
  • water
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45
Q

Describe carbon sources

A

Simple carbohydrates such as sugars and proteins. Some organisms are able to fix or steal CO2 from the air

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46
Q

Describe nitrogen sources

A

Proteins, peptides and amino acids, DNA, nitrates, ammonium salts
Some organisms can fix or steal nitrogen right from the air

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47
Q

Describe fastidious bacteria

A

Require more complex organic molecules such as blood and vitamins go grow.

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48
Q

True or false human pathogens are usually mesophiles

A

True. They require a temperature of 20-40° to grow. Other bacteria can grow below 15° and above 45°

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49
Q

What does oxygen act as in AEROBIC organisms

A

Acts as a final electron accepter

50
Q

True or false: ANAEROBIC organisms can detoxify o2

A

False. Anaerobic organisms lack the means to detoxify O2

51
Q

What is iron required for

A

Iron is required for enzyme action (cofactor). Bacteria produces sidedophores which bind to iron and make it possible to import it

52
Q

What pH do bacteria prefer

A

They prefer a neutral pH. Bacteria tends to die in acidic (<6) solutions which is why things can be preserved in vinegars etc

53
Q

Why do bacteria need to be in water

A

Bacteria require soluble nutrients for diffusion into the cell. So it thrives in water

54
Q

How does bacteria multiply?

A

Bacteria multiply through BINARY FISSION. A single cell separates to form two new cells and so on. Multiply rapidly

55
Q

What can limit the growth of bacteria?

A

Availability of nutrients, temperature (too hot or too cold) and the ability to remove toxic products as they can accumulate and damage the cells

56
Q

What is generation time?

A

The time required to divide, most organisms it is measured in minutes

57
Q

Why does honey preserve well?

A

Sugar content. Lots of sugar makes it very difficult for bacteria to grow

58
Q

What are the phases of growth of microbial populations?

A
  1. Lag phase
  2. Log phase
  3. Stationary phase
  4. Death phase
59
Q

Describe the lag phase

A

First phase. Bacteria first introduced and beginning to adapt to environment. Active synthesis of enzymes and other constituents

60
Q

Describe the log phase

A

Second phase. Bacteria begins rapidly growing, antibiotics most active during this phase

61
Q

Describe the stationary phase

A

Third phase. Reproduction rate equals death rate, nutrients begin to deplete and toxic materials begin to accumulate

62
Q

Describe the death phase

A

Death rate exceeds reproduction rate. Final phase.

63
Q

Describe active transport

A

Enzymes move substrate into the cell, requiring energy.
Concentration inside the cell is higher than the outside (working against gradient)
By pumping from the INSIDE out organisms can become resistant to antibiotics

64
Q

Describe group translocation

A

Enzymes modify a substance as it enters the cell.
Diffusion of the altered substrate is reduced
Energy is required

65
Q

Describe facilitated diffusion

A

Enzymes aid diffusion but no energy is required (passive transport)
Molecules must bind to specialized membrane proteins in order to be shuttled in
No modification of substrate
Concentration inside does not exceed exterior concentration

66
Q

Describe listeria monocytogenes

A

AEROBIC gram POSITIVE rod
Preferred pH 4.6-9.2
Grows best in refrigerator temperature

67
Q

Describe anabolism

A

Building organic molecules using smaller molecules and energy

68
Q

Describe Catabolism

A

Breakdown of chemical nutrients with release of energy

69
Q

What is ATP

A

Adenosine triphosphate. How cells store energy

70
Q

How do cells get energy?

A
  • nutrients
  • sunlight in some specialized species
  • using oxygen and other substances to accept electrons
71
Q

What is glycolysis

A

Catabolism
Glucose is broken down to pyruvic acid
Series of steps from 6 carbon molecule to TWO 3 carbon molecules
Products can enter respiration or fermentation

72
Q

Describe aerobic respiration

A

Krebs cycle
Pyruvate degraded to CO2 and H2O
Only in AEROBIC organisms
Results in more energy production

73
Q

Describe electron transport chain (Aerobic)

A

Electrons pass along the electron transport chain to terminal electron acceptor (O-)
A lot of energy is generated by ATP synthesis as protons flow down the proton gradient

74
Q

Describe fermentation

A

Anaerobic process. Electrons are transferred to form other organic compounds (ex.ethanol) instead of oxygen.
Different bacteria produce different products (ex.cheese, wine, beer)
Only two ATP produced from one glucose

75
Q

What are facultative anaerobes

A

Use respiration in air and can switch to fermentation I’d there is no oxygen

76
Q

Describe lipid catabolism process

A

Lipase: breakdown lipids -> glycerol -> glycolysis

Fatty acids are oxidized

77
Q

Describe protein catabolism

A

Proteases digest protein
Protein -> amino acids -> protein synthesis or further breakdown

Once it becomes a carbohydrate it is fed into the Krebs cycle

78
Q

Describe sanitizing

A

Removing of debris. Rendering safe to handle. Happens before disinfection.

79
Q

Describe disinfection.

A

Reduction in number of microbes present

80
Q

Describe sterilization

A

Elimination of all forms of life except prions

81
Q

How do disinfectants reduce number of organisms

A

By the microbial death rate. Constant for combo of circumstances (bug,agent,temperature)
At low levels of disinfection some bacteria may be inhibited rather than killed

82
Q

What is the mechanism of action of disinfectants

A

Proteins denaturation or by membrane damage

83
Q

Describe denaturation of proteins

A

Results in loss of secondary and tertiary structure with consequent loss of function.
One way step can not go back after this has happened

84
Q

Describe some disinfectant methods

A
  • using chemicals (antiseptics, bactericide, bacteriostatic agent)
  • pasteurization (using moderate heat)
  • preservation (drying, osmotic methods, reduces numbers and prevents Re growth)
85
Q

What factors are important in chemical disinfectant activity

A

Concentration of chemical
Time of exposure to disinfectant
Number and type of microbes present
Nature of material to be disinfected

86
Q

What is the mode of action of chemical disinfectants

A

Disruption of cell membranes

Denaturation of proteins

87
Q

What will low level disinfectants do

A 
Kill vegetative (actively growing) Bacteria, enveloped viruses and some fungi 
Often used for environmental and non critical equipment cleaning
88
Q

What will intermediate disinfectants do

A

Kill all bacterial pathogens(except spores), most fungi, most viruses

89
Q

What do phenol based disinfectants do?

A

Disrupt cell membranes and precipitate proteins

90
Q

What do alcohol disinfectants do

A

Denature proteins
70% alcohol is more effective than 100%
Requires adequate time for activity however

91
Q

What are the 2 types of oxidizing disinfectants

A

Halogens (bleach, iodine, chlorine)

Hydrogen peroxide

92
Q

Describe halogens

A

Iodine, bleach, chlorine, fluorine
Used in water supplies or for handling blood spills
Inactivated by organic materials, activity drops after opening
Corrosive
Risk of chlorine gas if acidified

93
Q

Describe hydrogen peroxides

A

Intermediate to high level disinfection. Some used as chemical sterilants
Active in presence of organic materials
Detergent properties which improves cleaning ability
Widely available in wipes etc

94
Q

What is peracetic acid

A

Hydrogen peroxide combined with acetic acid
Powerful highly reactive disinfectants
Not affected by protein or enzymes

95
Q

What is performic acid

A

H2o2 (hydrogen peroxide) combined with formic acid
Powerful highly reactive disinfectant
Not affected by protein or enzymes

96
Q

What are high level disinfectants

A

Substances able to kill spores, tubercle bacilli and viruses given enough time
Ex. Ortho-phthalaldehyde
With sufficient time of exposure and concentration these agents become chemical sterilants

97
Q

What is UV disinfectant used for

A

Water, waste water, air and surface disinfection

98
Q

Describe antiseptics

A

Disinfectants that are safe for use on skin, take time to work
Resistance can develop to these if too much use
(Ex. Alcohols triclosan (used for hand washing))

99
Q

What are transient flora?

A

Organisms that are acquired on hands during routine work, can include resistant organisms, easily transmitted
Carriage (carrying flora) can be eliminated by hand washing

100
Q

Describe the methods of sterilization

A
  • heat (dry or moist)
  • gas and liquid (good for things that can’t handle heat)
  • irridiation
  • filitration (doesn’t eliminate viruses, used as disinfectant in pharmacies)
101
Q

Describe autoclaving

A

Form of sterilization using moist heat at increased pressure for a defined time
Used on surgical instruments
Should be checked often

102
Q

Describe gas sterilization.

A

Requires an aeration step after sterilization.

Icludes ethylene oxide, formaldehyde gas, hydrogen per oxide vapour

103
Q

Describe radiation sterilization

A

Used in industry for plastic objects, fluid, (not use much in hospitals)
Uses microwave or gamma radiation.

104
Q

Describe prions

A

Caused by transmissible misfiled proteins
No nucleic acid and found in neurological tissue
Agents are RESISTANT to disinfection or sterilization with radiation or gas

Fabrics must be incinerated and materials that just be kept have to be sterilized in alkaline conditions and autoclaved

105
Q

What are the different relationships between hosts and microbes

A

Commensal
Normal flora (micro biome)
Opportunist

106
Q

Describe commensal relationship

A

Microbe received benefit but no harm to host

107
Q

Describe opportunist relationship

A

Microbe received benefit, and is able to cause disease if host defenses are weakened

108
Q

Define pathogenicity

A

The ability of an organism to cause disease

109
Q

Define virulence

A

The extent to which an organism can cause severe disease

110
Q

What forms of transmission of infection is there

A

Micro biome, people, animals, environment, vectors and fomites

111
Q

Defines vector

A

A small organism (insect or tick) that transmits and infectious agent

112
Q

Define fomites

A

An inanimate object that transmits infection when contaminated
Ex. Door knob
Very common

113
Q

What are exotoxins

A

Toxins excreted from the bacterial cell
May disrupt cells or interfere with their function
Ex. Tetanus

114
Q

What are virulence factors

A

Properties that enable organism to infect
May enable organism to invade hosts Defenses via a slime layer
May improve access to bodies nutrients via colonization factors (fimbrae)

115
Q

What substances help organisms invade

A
  • hemolysins: cause lysis of red blood cells and damage body cells
  • leukocidins: kill white blood cells
  • hyaluronaise: break down connective tissues
  • collagenease: break down collagen
116
Q

Examples of bacterial toxins ?

A
  • enterotoxins (gut)
  • neurotoxins
  • protein synthesis inhibitors (kill or damage organs, diphtheria)
  • superantigens
117
Q

Describe super antigens

A

Toxins that bind to macrophages and short circuit the mechanism that stimulates the immune system causing a dramatic response and damage to the body
Ex toxic shock syndrome

118
Q

Describe endotoxin

A

Substance found in the outer membrane of gram NEGATIVE organisms (not an exotoxin)
Causes fever, BP drop leading to poor organ perfusion
Acts by binding macrophages and causing release of active substances (cytokines)

119
Q

How does DNA transfer between organisms?

A

Conjugation
Transformation
Transduction

120
Q

Describe conjugation

A

Transfer of genetic material (nucleic acid) by direct contact if cells especially important in gram NEGATIVEs
Mediated by pili
Allows transfer of plasmids

121
Q

Describe transformation

A

Free extra cellular DNA can be taken up by some bacteria and incorporated to the bacterial genome
(Pick up DNA floating around and transform )
(Strep and pneumonia good at this)

122
Q

Describe transduction

A

Genetic material is transferred via a bacterial virus (bacteriophage) infection of the bacteria 2 things happen:
Phage takes over bacteria and rapidly destroys it (lytic infection)
Phage incorporates with bacteria and gives it new properties (transduction)
Bacteriophages can treat infections in some cases

MICI module 1 (4 decks)

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