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Microbiology-1 > Antibiotics > Flashcards

Antibiotics Flashcards

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1
Q

Unwinding of the DNA is due to the action of enzymes such as?

A

Helicase, DNA Gyrase, and topoisomerase which break the hydrogen bonds between bases and or hold part of the strand stable.

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2
Q

What inserts complementary nucleotides thereby generating a new strand?

A

DNA Polymerase

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3
Q

Where are nucleotides always added?

A

the 3’ end. Strand grows in the 5’ to 3’ direction.

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4
Q

Which end is exposed in the lagging strand faces toward the fork?

A

has the 5’ end exposed facing toward the fork

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5
Q

What is needed to initiate strand growth in the absence of a nucleotide having a 3’ binding site?

A

RNA Primer and RNA polymerase

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6
Q

The RNA primer provides?

A

a 3’ site

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7
Q

What joins the final nucleotide of the new fragment to the existing strand?

A

DNA Ligase

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8
Q

What carries the genetic code from the DNA to the ribosome?

A

Messenger RNA mRNA

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9
Q

Transports and then transfers the amino acid to the developing peptide chain

A

Transfer RNA

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10
Q

What does the anticodon specify?

A

Which amino acid will be carried by the tRNA

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11
Q

What assists protein synthesis by serving as a facilitator for the mRNA and the tRNA functions?

A

Ribosomal RNA

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12
Q

The transfer of the genetic code on DNA gene into a messenger RNA (mRNA) strand by means of DNA-dependent RNA polymerase.

A

Transcription

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13
Q

Where does RNA polymerase bind to the DNA at?

A

the promoter site

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14
Q

What joins the complementary RNA nucleotides together in sequence?

A

RNA polymerase?

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15
Q

When does transcription end?

A

the RNA polymerase reaches the termination region of the gene and the new single-stranded mRNA is released.

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16
Q

The synthesis of a polypeptide at the ribosome through linkage of amino acids in a sequence specified by mRNA molecule

A

Translation

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17
Q

Where does the mRNA attach to during translation?

A

the start codon

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18
Q

A tRNA with the complimentary anticodon matches to the codon on the mRNA does what?

A

brings the first amino acid into place

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19
Q

the tRNA is released when?

A

As the mRNA codons are matched with complementary tRNA anticodons, the amino acids are linked togethers and the tRNA is released.

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20
Q

When is the polypeptide chain released during translation?

A

when the reading frame reaches the stop codon

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21
Q

these are constantly expressed

A

constitutive genes

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22
Q

genes that can be turned on

A

inducible genes

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23
Q

genes that can be turned off

A

repressible genes

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24
Q

related genes that are regulated as a group/series

A

Operon

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25
Q

Codes for a “repressor” protein which can bind tot he “operator” region

A

Repressor gene

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26
Q

Region of the chromosome which the RNA polymerase binds to during transcription

A

Promoter site

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27
Q

Region of the chromosome which controls access of the RNA polymerase to the structural genes of the operon; site to which the repressor protein bind.

A

Operator site

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28
Q

Adjacent genes of the operon which direct the synthesis of proteins with related functions and which are regulated as a unit

A

Genes of the Operon

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29
Q

Genes are expressed only when certain environmental conditions are present

A

Inducible operon

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30
Q

Genes are expressed except when certain environmental conditions are present

A

Repressible operon

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31
Q

Changes in the sequence of DNA bases, thus changing the genetic code

A

Mutation

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32
Q

What may cause protein changes that may result in changes to metabolic, antigenic, or structural features?

A

Mutations

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33
Q

What are the two types of mutations?

A

Base Substitution

Frameshift

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34
Q

a single base is replaces with another, thus changing the codon. may results in an improper amino acid in the protein

A

Base substitution

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35
Q

What are the three types of base substitution?

A

Silent
Missense
Nonsense

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36
Q

Insertion or deletion of bases may shift the codon reading frame of the mRNA in the ribosome

A

Frameshift

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37
Q

What does frameshift mutation usually result in?

A

missnse and sometimes in significantly different, nonfunctional, or incomplete protein

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38
Q

What three things are mutations caused by?

A

Spontaneous mutation
Chemical Mutagens
Radiation

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39
Q

gain, loss or substitution of entire gene segments or inversions or transpositions of gene sequences to form new combination of genes.

A

Recombination

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40
Q

Small, circular self replicating piece of DNA in bacteria

A

Plasmid

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41
Q

What is separate from the normal chromosomal DNA?

A

Plasmid

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42
Q

What genes often code for antibiotic resistance or diseases causing factors and can be used in the genetic engineering process?

A

Plasmid

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43
Q

Integration of the DNA of a temperate bacteriophage into the bacterial chromosome where it replicates along with the bacterial chromosome?

A

Lysogeny

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44
Q

Mutation
Viral gene may code for antibiotic resistance or diease-causing factors and produces new bacteriophage upon separation from the bacterial DNA

A

Lysogeny

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45
Q

The transfer of genetic material between donor and recipient cells involving direct cell to cell contact, uses a sex pilus.

A

Conjugation

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46
Q

The direct uptake of DNA segment from one bacterium to another as “naked” DNA in solution. Results in new characteristics for the recipient cell.

A

Transformation

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47
Q

The transfer of DNA from donor bacterium to recipient bacterium by using a bacterial virus as the vehicle. Results in new characteristics for the recipient cells, bacteriophage is not functional

A

Transduction

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48
Q

Agents having no known potential for infecting healthy people

A

BSL-1

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49
Q

Agents most commonly encountered in clinical samples such as HIV and requires lab coat and gloves

A

BSL-2

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50
Q

Agents include those that are more unusual or more highly transmissible such as TB, precautions include level 2 plus routine use of BSC, and HEPA mask

A

BSL-3

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51
Q

Agents are certain highly infectious exotic microbes and toxins for which there is no vaccine or effective treatment and that require the maximum containment facilities

A

BSL-4

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52
Q

Free of all microorganisms and their spores

A

Sterile

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53
Q

Use of physical procedures or chemical agents to destroy all microbial forms, including bacterial spores.

A

Sterilization

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54
Q

Use of physical procedures or chemical agents to destroy, inhibit, neutralize, or remove at least most potentially infectious microorganism on an object or surface.

A

Disinfect

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55
Q

agent or method used to carry out disinfection; normally used on inanimate objects

A

Disinfectant

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56
Q

Use of chemical agents on the skin or other living tissue to eliminate or inhibit microorganisms; no sporicidal action is implied.

A

Antisepsis

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57
Q

-cide -cidal

A

kills the microbe

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58
Q

-stat, -static

A

prevents growth or multiplication of bacteria

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59
Q

Sporicidal

A

destroys spores

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60
Q

Free of contaminating or infectious microorganisms

A

Aseptic

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61
Q

easily altered, decomposed or destroyed by heat

A

Thermolabile

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62
Q

not easily altered, decomposed or destroyed by heat

A

Thermostable

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63
Q

What are the factors affecting the effectiveness and choice of sterilization or disinfection method/agent?

A

Microbial population composition
Microbial death
Population size
Concentration/intensity of antimicrobial
Duration of exposure
Temperature and pH
Presence of protective or neutralizing matter
Physical nature of materials being treated.

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64
Q

What is the order of overall degree of microbial resistance to killing?

A 
Bacterial endospores 
Mycobacterium 
Protozoan cysts 
Non-enveloped small viruses 
Vegetative bacteria 
Fungi
Enveloped viruses
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65
Q

What dies more rapidly: vegetative cells or spores?

A

Vegetative cells

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66
Q

A larger quantity of contaminating microbes requires a shorter or longer exposure time to destroy?

A

longer

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67
Q

The longer a population is exposed to a microbicidal agent, the more?

A

organisms are killed

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68
Q

what can inactivate enzymes or denature molecules?

A

Temperature

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69
Q

What can directly kill microbes or may enable chemical disinfectants to inactivate microbes faster?

A

Acids

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70
Q

This material protects or inactivates chemical disinfectants, it can protect microorganisms from heating and chemical disinfectants.

A

Organic matter

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71
Q

What are the modes of action of microbial control methods?

A

Damage to cell wall
Disrupt cytoplasmic membrane
Inhibit synthesis of proteins and nucleic acids
Alter function of proteins & nucleic acids

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72
Q

What does damaging the cell wall do ?

A

Block its synthesis, digest it, or break down its surface

antibiotics, lysozyme, detergents

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73
Q

What does disrupting the cytoplasmic membrane do?

A

Cause loss of membrane integrity and selective permeability

detergents (surfactants), heat

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74
Q

What does inhibiting synthesis of proteins and nucleic acids do ?

A

Interference with gene translation, thus preventing protein synthesis
(antibiotics, radiation, formaldehyde)

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75
Q

What does altering the function of proteins and nucleic acids do?

A

Alters bonds that determine secondary and tertiary structure. Altered structure inactivates or denatures functions of enzymes and nucleic acids
(heat, strong organic solvents, phenolics, metallic ions, and antibiotics)

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76
Q

What are the methods of physical control of microorganisms?

A

Cold temperature
Heat (moist, dry, steam, incineration)
Radiation
Filtration

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77
Q

What does heat do to the cells of the microbe?

A

kills cells by disrupting cell membrane functions, denaturing proteins, and inactivating nucleic acids.

Cell membranes become more fluid at elevated temps, causing them to lose their selective permeability

Proteins and nucleic acids are inactivated by breaking their hydrogen bonds, which unfolds proteins and separates double-stranded nucleic acids.

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78
Q

What heat is more effective than dry heat? Why?

A

Moist heat

Moist heat possesses greater heat energy than dry heat

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79
Q

What are the conditions of dry heat?

A

160 to 180 degrees Celsius for two hours

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80
Q

What is dry heat used for?

A

thermostable non-liquid- metal or glass

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81
Q

What are the disadvantages of dry heat oven?

A

liquids cannot be heated above boiling point

organic compounds may denature above certain temps

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82
Q

What are the conditions of steam heat (autoclave)?

A

121 degrees Celsius for 15 minutes. Large loads may require more than 1 hour so moisture can penetrate all items in the load

The high pressure in the autoclave counteracts vaporization so that heat stable liquids can be heated to 121 Celsius under 15lb of pressure without boiling over. High pressure does not cause the killing

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83
Q

What are the limitations of steam heat?

A

Cannot be used for certain thermolabile substances

Cannot be used for items adversely affected by moisture- surgical instruments with sharp cutting edges

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84
Q

What are the uses of Steam heat?

A

Sterilization of clean, wrapped instruments, containers and microbial culture media
To render contaminated materials biologically safe before they are discarded

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85
Q

What does ionizing radiation- gamma do?

A

Nonspecifically alters cellular proteins and nucleic acids by penetrating deep into objects

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86
Q

What is gamma radiation used for?

A

Used to sterilize pharmaceuticals, medical/dental supplies, and items that cannot withstand the heat of steam sterilization or the effects of chemicals.

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87
Q

What does ionizing radiation- electron beam radiation do?

A

Alters nucleic acid

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88
Q

What is electron beam radiation used for?

A

Used to decontaminate packages by the postal service

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89
Q

What does ultraviolet non-ionizing radiation do?

A

Nucleic acids mutations that prevent normal gene expression and DNA replication.

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90
Q

What are the conditions of ultraviolet non-ionizing radiation

A

Optimum wave length- 240 to 280 nm (optimum 252 nm)
Low penetrating power- must have direct contact with organism .
Requires lengthy exposure- 10 seconds to 30 minutes depending on distance from UV light source.

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91
Q

What are membrane micropore filters?

A

membrane of cellulose acetate & cellulose nitrate that has a complex system of pores that trap microbes by pore size and chemical affinity to the matrix.

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92
Q

What are the conditions of membrane micropore filters?

A

Pore size- 0.22 micron is usually effective in removing all bacteria
Moderately effective on viruses, mycoplasma, chlamydia, and rickettsia
Used for sterilization of thermolabile liquids.

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93
Q

What are the conditions of the HEPA filter?

A

consist of randomly oriented glass and polymer fibers that effectively remove 99.97% of particles 0.3um and larger.

highly effective at containing particles between 0.3 and 0.1 um and smaller.

Removal of particles is accomplished by adherence of particles to the fibers rather than by sieve in common paper filters.

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94
Q

What does boiling heat kill?

A

vegetative bacteria and resistant bacteria

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95
Q

What does dry heat sterilize?

A

certain thermostable items- glassware

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96
Q

What are disadvantages of the autoclave?

A

Limited volume; costly equipment; thermostable items only

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97
Q

What are the disadvantages of the membrane micropore filtration?

A

Viscous fluids clog; viruses pass through most filters

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98
Q

What are the disadvantages for the HEPA filter?

A

Its for air only
does not remove chemicals
not 100% removal

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99
Q

What are the disadvantages of ultraviolet radiation?

A

Not penetration through regular glass
danger to eyes
lengthy exposure

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100
Q

What are the disadvantages of electron beam?

A

Direct exposures; small containers

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101
Q

What are the disadvantages of gamma rays?

A

Danger to humans; requires special containment.

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102
Q

What are high-level disinfectants (definition)?

A

microbicidal and sporicidal, although some may do so slowly. may become sterile under certain conditions.

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103
Q

What are intermediate-level disinfectants (definition)?

A

Most commonly employed products. effective against vegetative forms of bacteria and maybe effective against fungi and viruses, but a few products will be sporicidal. A few are antiseptics.

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104
Q

What are low level disinfectants (definition)?

A

usually bactericidal; not sporicidal; or tuberculocidal often not fungicidal or virucidal

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105
Q

What disrupts structural proteins & enzymes?

A

Glutaraldehyde

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106
Q

What kills vegetative bacteria within minutes and spores in 3-10hr; active solution unstable?

A

Glutaraldehyde

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107
Q

What are the three high disinfectants?

A

Glutaraldehyde
Hydrogen Peroxide- vap
Chlorine Compounds-gas

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108
Q

What are the two sterilants?

A

Glutaraldehyde

Hydrogen Peroxide- vap

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109
Q

What is an intermediate disinfectant?

A 
Hydrogen peroxide- ag 
Phenolic compounds 
Chlorine- hypochlorite 
(Alcohol)
(quaternary ammonium)
(Chlorhexidine)
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110
Q

What are the low level sporicidals?

A

Chlorine compounds

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111
Q

What are the antiseptics?

A 
Hydrogen Peroxide- aq
Iodophors
Alcohol 
Quaternary ammonium
Chlorhexidine
112
Q

What are corrosive?

A

Phenolic compounds

Chlorine compounds

113
Q

Which are inactivated by organic material?

A

Hydrogen peroxide- minimal
Chlorine Compounds
Iodophors
Alcohol- minimal

114
Q

What creates a formation of hydroxyl free radicals which are toxic to cells?

A

Hydrogen Peroxide

115
Q

What sterilizes in 6 hours and disinfects in 2-30 minutes?

A

Hydrogen Peroxide

116
Q

What disrupts cell walls and membranes; precipitates proteins?

A

Phenolic compounds

117
Q

What inactivates enzymes; damages membranes?

A

Chlorine Compounds

118
Q

What disrupts metabolic enzymes?

A

Iodophors

119
Q

What dissolves membrane lipids; may coagulate protein?

A

Alcohol

120
Q

What is a surfactant, destroys cell membrane; denatures proteins?

A

Quaternary ammonium

Chlorhexidine

121
Q

What kills vegetative bacteria within a few minutes, a skin irritant, and D-2-30minutes?

A

Phenolic compounds

122
Q

What is fact acting, skin & lung irritant, bleach decomposes in a few days; high level disinfection 1-6 hours, regular D 20-30 minutes?

A

Chlorine Compounds

123
Q

Some residual effect; uses high concentration for equipment. D 2-30 minutes

A

Iodophors

124
Q

Inactivated somewhat by organic matter. Mild skin and lung irritant; dries skin, flammable, D 1-10 minutes?

A

Alcohol

125
Q

Benzalkonium=50% up to 80%. Toxic if ingested. Disinfection of 1-10 min.

A

Quaternary ammonium

126
Q

Residual effects; soluable in water and alcohol; low toxicity. D- few minutes

A

Chlorhexidine

127
Q

What is a chemical substance of natural, semisynthetic or synthetic origin that inhibits or kills microorganisms and can be used to treat or control infection?

A

Antibiotic

128
Q

What are the inhibitors of cell wall synthesis?

A

Beta-lactams- Penicillin’s, Cephalosporins
Vancomycin
Bacitracin
Isoniazid

129
Q

What inhibits peptidoglycan synthesis by inhabiting the formation of crosslinks between the polymers of the bacterial cell wall?

A

Beta-lactams

130
Q

What are cell-membrane enzymes responsible for synthesizing peptidoglycan?

A

Penicillin binding proteins (PBP)

131
Q

How do beta-lactam antibiotics act?

A

By binding to PBPs

132
Q

What does binding to the PBP result in?

A

Inhibition of peptidoglycan synthesis
Degradation of formed cell wall through the release of autolytic enzymes
Weakend cell wall loses integrity and can no longer preserve osmotic pressure. Results in cell death and increased phagocytosis.

133
Q

What acts poorly against existing peptidoglycan and is primarily effective against growing bacteria?

A

Beta Lactams

134
Q

What are some characteristics of beta lactams?

A

Very low toxicity
Generally bactericidal
Different groups/generations have different spectrums and resistance

135
Q

Resistance of beta-lactams can occur due to?

A

Development of changes to pores thus preventing entrance of antibiotic
Prevention of binding of antibiotic to PBP due to modified PBP structure
Hydrolysis of antibiotic by beta-lactamases

136
Q

Binds onto the cross-link peptide, so that the link cannot be completed and peptidoglycan polymer cannot elongate.

A

Vancomycin

137
Q

Blocks phospholipid carrier that helps carry subunits of peptidoglycan across membrane to cell wall

A

Bacitracin

138
Q

Inhibits formation of mycolic acid in cell walls of mycobacterium (TB)

A

Isoniazid

139
Q

What are the inhibitors of protein synthesis

A

Chloramphenicol, Clindamycin
Erythromycin
Aminoglycosides
Tetracyclines

140
Q

What inhibits accurate translation of mRNA or polypeptide chain formation at the bacterial ribosome?

A

Inhibitors of protein synthesis

141
Q

What inhibits the polypeptide elongation steps in translation by binding to 50S ribosome subunit and blocking peptide bond formation?

A

Chloramphenicol, Clindamycin

Bacteriostatic
Broad spectrum
Resistance- due to chemical alteration of either the antibiotic or the ribosomal unit.

142
Q

Binds to 50S subunit; prevents translocation

A

Erythromycin

143
Q

Inhibits translation by binding to 30S ribosomal protein causing misreading of mRNA and incomplete synthesis of protein molecules?

A

Aminoglycosides

Bactericidal
Broad-spectrum
Resistance-most commonly results from enzymatic modification of the antibiotic

144
Q

Inhibits translation into polypeptides (proteins) by blocking binding of tRNA to the 30S ribosome mRNA complex?

A

Tetracyclines

Bacteriostatic
Broad-spectrum
Resistance most commonly results from active efflux of the antibiotic out of the cell or the production or proteins that protect the 30S ribosome.

145
Q

What are the inhibitors of cell membrane function?

A

Ploymyxins

Amphotericin B

146
Q

What disrupts functional integrity of cytoplasmic membrane, allowing nucleotides and proteins to escape?

A

Inhibitors of cell membrane

147
Q

Active against gram-negatives, nephrotoxic

A

Polymyxins

148
Q

Anitfungal; binds with ergosterol in fungal membranes; somewhat toxic

A

Amphotericin B

149
Q

What are the inhibitors of nucleic acid?

A 
Quinolones
Rifampin 
Metronidazole 
Nucleoside analogues
Flucytosine, 5-fluorocytosine (5FC)
150
Q

Competitive inhibition of essential nucleic acid precursor or binds essential enzyme

A

Inhibitors of nucleic acid

Most are bactericidal and moderately narrow-spectrum

151
Q

Inhibits bacterial DNA gyrase

A

Quinolones

152
Q

Inhibits transcription by binding to RNA polymerase and inhibiting initiation of mRNA synthesis

A

Rifampin

153
Q

Inhibit DNA or RNA synthesis by altering their composition using nucleic acid analogues

A

Nucleoside analogues

Antiviral, antimicrobics

154
Q

Incorporates into fungal RNA and interferes with DNA and protein synthesis

A

Flucytosine, 5-fluorocytosine

155
Q

What is the resistance of inhibitors of nucleic acid due to?

A

typically because decreased uptake into the cells dur to cell wall or cell membrane molecular changes

156
Q

What are the inhibitors of bacterial metabolism?

A

Sulfonamides
Trimethoprim
Azoles

157
Q

Inhibits folic acid synthesis by competing for precursor molecules

A

Sulfonamides

158
Q

Competitively interferes with folic acid production by inhibiting a metabolic enzyme

A

Trimethoprim

159
Q

Antifungal- inhibits synthesis of ergosterol, a key structural molecule of fungal cell membranes?

A

Azoles

160
Q

Rapid, sensitive but possible less specific, less expensive

A

Screening/Presumptive

161
Q

Less rapids, more specific, more expensive

A

Definitive/Confirmatory

162
Q

To dilute the specimen in order to obtain colonies which are physically separated from each other

A

Isolation

163
Q

Major types of culture mediA

A

Nutrient

Enriched- provides general nutrients plus various enrichments for fastidious bacteria

Selective- contains ingredients that restrict the growth of certain types of bacteria

Differential (detects pH changes)

164
Q

What does Blood Agar Plate not grow?

A

Neisseria gonorrhoeae

Haemophilus infuenzae

165
Q

This media colonies can be differentiate by hemolytic pattern- (alpha, beta, gamma)

A

Blood Agar Plate

166
Q

What grows most medically significant bacteria?

A

Supplemented Chocolate Agar

167
Q

What grows gram negative bacilli?

A

MacConkey Agar

168
Q

What is used for blood culture & other specimens?

A

Broth media (liquid)

169
Q

What is hemolysis due to on blood agar plate?

A

bacterial production of enzymes which alter the hemoglobin of red blood cells

Alpha- green zone
Beta- clear zone
Gamma- no change

170
Q

Tests for presence or production of certain enzymes or metabolic products

A

Biochemical Identification Tests

171
Q

What are the bacterial identification?

A

Gram Stain
Culture Characteristics
Biochemical Tests
Time to ID- 6-48hr

172
Q

What is yeast grown on? How is it identified?

A

Blood agar plate

Microscopy
Biochemical tests
antigen tests

173
Q

What do molds grow on?

A

media with antibiotics

Direct microscopic exam of specimen, microscopic exam of culture; few biochemical tests; few antigen detection tests

174
Q

What do viruses grow on?

A

grow in living tissue culture cells

antibody detection; antigen detection; gene probe

175
Q

Epitopes must be _____ and sufficient quantity needed

A

detectable

176
Q

Epitopes must be highly ______ in order to produce accurate test results

A

specific

177
Q

What can cause a false positive results?

A

Possibility if Cross-reactive- some Ab Fab sites will bind with very similar, but incorrect antigens

178
Q

The ability of the test to detect very low levels of antigen when it is present? All true positive are detected, includes a low percentage of false-positives.

A

Sensitivity

Expressed as (limit of detection) and (2) Percent Accuracy 
Test with high sensitivity may be used as initial screening or presumptive tests
179
Q

The ability of the test to accurately detect only the correct antigen or antibody while note reacting with incorrect antigen or antibody?

A

Specificity

Distinguish cross-reactive and false-positive results from true positives

180
Q

What does overall degree of accuracy of the immunological test depend on?

A

Quantity of antigen or antibody, exposure to antigen, and any cross-reactivity between non-matching antigen and antibody

181
Q

What are the four immunoassays?

A

LFI (lateral flow)
Agglutination
Immunofluorescence
ELISA

182
Q

Antigen-Antibody binding is visible by deposit of the bound molecules at the “test line”

A

LFI

183
Q

Specimen is deposited on one end of the membrane and a wicking pad draws the fluid contain the specimen and reagent through the membrane

A

LFI

184
Q

The reaction of a particle-sized antigen with its corresponding antibody resulting in macroscopic clumping.

A

Agglutination Method

185
Q

Relatively low sensitivity, specimen screening in clinic or early lab workup

A

Agglutination Method

186
Q

The reaction of the bound, labeled antibody with its corresponding antigen is made visible by exposure to ultraviolet light

A

Immunofluorescence Method

187
Q

Results available in real time, very sensitive and specific. Useful for certain types of agents

A

Immunofluorescence Method

188
Q

The reacted antigens and antibodies are exposed to a color producing substrate to make antigen-antibody reaction visible.

A

ELISA

189
Q

Very sensitive, and accurate test- results available from a few minutes to 2 days.

A

ELISA

190
Q

Increase the number of copies of significant microbial gene sequences so they can be detected. (PCR)

A

Gene Amplification

191
Q

What do you use to observe gram stain of bacteria?

A

Oil immersion- high power

192
Q

What do you observe KOH preparation for molds?

A

Low power

193
Q

What do you observe other wet mount preparations with?

A

Low or high dry power

194
Q

What are the steps of the smear prep of gram stain?

A

1) Smear Prep-
smear the specimen on slide
allow to dry in the air
Fix smear to slide by flooding the dry smear with methanol for about 1 minute

195
Q

What are the staining steps of the gram stain?

A
  1. Primary stain- crystal violet- 1 minute then rinse
  2. Mordant (Grams iodine)- 1 minute- then rinse with water
  3. Decolorizer (acetone & alcohol): 2-5 seconds, then rinse with water
  4. Counterstain (Safranin): 30 to 60 seconds, then rinse with water and allow to dry
196
Q

What are the examination procedure steps of gram stain?

A
  1. Allow the slide to dry without heating
  2. Focus on objects using the low power lens and low light intensity
  3. Change to oil immersion lens to observe details of bacteria; add a drop of oil to the slide, increase the light intensity; focus by using the fine focus knob
197
Q

What are the interpretation steps of gram stain?

A

Usually reported within 30 to 60 minutes
1. Reaction- Gram pos- blue-violet
Gram neg- pink-red
2. Report stain reaction, cell shape, and cell arrangementt

198
Q

Direct examination of certain unfixed specimens to permit examination of cells in their natural state

A

Wet Mount

199
Q

What power do you use a wet mount with?

A

low and/or high-dry power objectives and using reduced light intensity

200
Q

What are some of the wet mount examination types?

A

KOH
Yeast cells in CSF
Saline wet preparation of vaginal exudate -Trich

201
Q

To determine if the pathogen is susceptible or resistant to a particular set of antimicrobics

A

Antimicrobic Susceptibility Testing

202
Q

What is empiric therapy?

A

treating an antibiotic without antimicrobic susceptibility testing

203
Q

The microorganism is not inhibited by the max safe does/concentration of the antimicrobic.

A

Resistant

204
Q

The microorganism is inhibited (or killed) by the max safe dose/concentration of the antimicrobic. It is a candidate in treating this infection.

A

Susceptible

205
Q

The microbe may be inhibited by a high dosage that very near the resistant point. Typically interpreted as resistant.

A

Intermediate

206
Q

Determine which antimicrobics are effective against a particular bacterium at the breakpoint concentration of each antimicrobic.

A

Disk diffusion testing method

207
Q

What zone indicates that greater concentration of antibiotic has migrated farther away from the disk and/or the bacteria is killed at a low concentration?

A

A large zone

208
Q

Where will a zone of inhibition (no growth) occur?

A

Where the antimicrobic concentration is sufficiently high

209
Q

How are the zone sizes interpreted to susceptible, intermediate or resistant?

A

measurement of size of zone inhibition of growth is interpreted using a detailed chart that converts zone size into the three categories.

210
Q

Determines the minimum concentration of each antimicrobic agent that is effective against the bacterial pathogen

A

Minimum Inhibitory Concentration (MIC)

211
Q

Interpretation means the antibiotic concentration of at least 2 times the MIC can be achieved at the site of infection.

A

Susceptible

212
Q

Antibiotic concentration of 2X the MIC cannot be achieved even with the maximum safe dosage

A

Resistant and Intermediate

213
Q

The close association and interaction of two dissimilar organisms living together

A

Symbiosis

214
Q

Where are the areas of normal flora?

A 
Skin
Nasal
Mouth/Pharynx
Lower GI
Anterior Urethra 
Vagina
215
Q

Association between organisms in which one is benefitted and the other is neither benefitted nor harmed

A

Commensalism

216
Q

Both the microbe and the host derive benefits from the relationship

A

Mutualism

217
Q

What are the four things that can alter the normal flora host relationship?

A

Prolonged antibiotic therapy
Traumatic injury
Immunological compromise
Hormonal or chemical changes

218
Q

The growth and spread of a pathogen in or on a host resulting in injury to the host tissue

A

Infectious disease

219
Q

A microbe capable of causing disease by invading tissues, producing toxins, or both

A

Pathogen

220
Q

The degree of pathogenicity

A

Virulence

221
Q

What are the two things associated with virulence?

A

Infectivity - how easily the microbe survives the normal host defenses and establishes infection

Severity - of the damage it causes the infected host

222
Q

What are modes of transmission

A

Direct contact
Inhalation
Ingestion
Parental

223
Q

What are the Attachment factors that enable the establishment of infection?

A

Portal of entry
Attachment
Quantity
Quorum-sensing Regulators

224
Q

What are the three things of attachment?

A

Fimbrae
Surface Chemicals
Adhesive Matrix Molecules

225
Q

What attaches to specific receptor sites on specific tissue?

A

Fimbrae

226
Q

What dissolve covering of cells and aid chemical attachment?

A

Surface Chemicals

227
Q

What produces biofilms providing protection for bacteria within harsh human environments?

A

Adhesive Matrix Molecules

228
Q

What are the Antiphagocytic Factors?

A

Capsule
Leukocidin
Coagulase
Survival of phagocytosis

229
Q

Causes destruction of white blood cells

A

Leukocidin

230
Q

causes fibrin clot to form around the microbes

A

Coagulase

231
Q

Resistance to killing within a phagocyte

A

Survival of phagocytosis

232
Q

What are the Microbial virulence factors?

A 
Attachment & Establishment Factors 
Antiphagocytic Factors 
Invasive Enzymes 
Exotoxins 
Endotoxins 
Genetic Alterations 
Special Antimicrobic Resistance Situations
233
Q

Prevent microbe from being engulfed and/or destroyed by white blood cells

A

Antiphagocytic Factors

234
Q

Factors that promote the invasion and spread of a pathogen in/on the tissue

A

Invasive Enzymes

235
Q

What are the invasive enzymes?

A 
Collagenase 
Lecithinase 
Hylauronidase 
Fibrinolysin & Streptokinase 
Hemolysins 
Lipase 
Proteases 
Super Antigens
236
Q

Breaks down collagen fibers

A

Collagenase

237
Q

Destructive to cell membranes of red blood cells and other tissue cells

A

Lecithinase

238
Q

Breaks down hyaluronic acids in cell membranes

A

Hyaluronidase

239
Q

Lyses fibrin in blood clots thus preventing isolation of the infection

A

Fibrinolysin & Streptokinase

240
Q

Dissolve red blood cell membranes

A

Hemolysis

241
Q

Digest lipids allowing bacteria to enter

A

Lipase

242
Q

Digest proteins (IgA) thus permitting bacteria to evade entrapment, digestion, etc.

A

Proteases

243
Q

Cause exacerbated immune or inflammatory response

A

Super Antigen

244
Q

Cytolytic and Receptor-binding proteins

Many are dimeric A&B subunits

A

Exotoxins

245
Q

Tissues affected are vey defined and limited
Super antigens are special group of toxins
Often coded on plasmid of lysogenic phage

A

Exotoxins

246
Q

Cause specific widespread biological effects on the body, highly potent and elicit good, protective antibodies

A

Exotoxins

247
Q

“Lipid A” component of gram-negative cell walls which is released upon disintegration of the cell.

A

Endotoxin

248
Q

Binds to CD14 and TLR 4 on macrophages, B-cells.

A

Endotoxin

249
Q

Endotoxin stimulates production and release of Acute-phase Cytokines - IL-1, TNF, IL-6 which does what?

A

Triggers white blood cells to discharge chemicals which induce fever, pain, hemorrhage, blood pressure drops

250
Q

Does not elicit very good or protective antibodies?

A

Endotoxin

251
Q

Gram-negative bacillus cell wall sloughs off or disintegrates is an example of?

A

Endotoxin

252
Q

What is code for some exotoxins, antibiotic resistance, and invasive enzymes? passed by conjugation

A

Plasmid

253
Q

Viral DNA incorporated into bacterial DNA, code for some exotoxins and invasive enzymes?

A

Lysogeny

254
Q

Pieces of genetic material from one organism are incorporated into the genetic material of another organism.

A

Gene Recombination,.

255
Q

Many bacteria gain antibiotic resistance by?

A

Mutated genes
Plasmid encoded genes
Lysogenic virus

256
Q

Presence of an antibiotic-resistant bacterium in the community/hospital leads to?

A

Survival of the mutant
Increasing numbers of the mutant in the population
Disease problems increase and spread to new geographic locations

257
Q

Bacterial enzyme that inactivates many beta-lactam antimicrobics

A

Beta Lactamase

258
Q

If a test report is positive for the plasmid encoded gene of beta-lactamase when what kind of antibiotic is used?

A

antibiotic that is resistant to beta-lactamase

259
Q

Version that affects a larger group of antimicrobics that are typically not affected by typical beta-lactamase

A

Extended Spectrum Beta-lactamase (ESBL)

260
Q

Mutated MecA gene

A

MRSA

261
Q

What does the mecA gene encode for?

A

a low-affinity penicillin binding protein (PBP2a).

262
Q

Mutates genes for outer membrane porins and PBP transpeptides

A

Carbapenem-Resistant Enterobacteriaceae

Carbapenem-Producing Enterobacteriaceae

263
Q 
A form of beta-lactamase 
Carried by plasmids 
Results in:
Loss of drug diffusion into periplasm 
Loss of cross-linking activity of PBP
A

Carbapenem-Resistant Enterobacteriaceae

Carbapenem-Producing Enterobacteriaceae

264
Q

What are the two host resistant factors?

A

Non-specific

Special Factors

265
Q

What are the nonspecific factors?

A 
Innate species immunity/resistance 
Physical/Mechanical Barriers 
Chemical barriers
Phagocytosis 
Inflammation
266
Q

What are the Physical/Mechanical Barriers?

A 
Skin
Mucous Membranes 
Cilia of Respiratory tract
Peristaltic action of gut 
Normal Flora
267
Q

What are Chemical barriers?

A 
Acid pH
Bile salts 
Lysozyme 
Antimicrobial chemicals from normal flora 
Interferon
268
Q

What does acid pH not denature?

A

Typhoid & tubercule bacilli, protozoan cysts, polio & hep A

269
Q

What does lysozyme digest?

A

Gram-positive

270
Q

Human host cell protein produced in response to invasion by certain viruses. It acts as a local defense against certain viruses by producing inhibiting substances that interfere with viral reproduction

A

Interferon

271
Q

Foreign particles are ingested and digested by polymorphonuclear leukocytes, monocytes, and macrophages

A

Phagocytosis

272
Q

This develops after mechanical injury or exposure to certain chemicals

A

Inflammation

273
Q

What is formed during inflammation to enclose the pus that contains phagocytes, dead microbes, dead tissue cells, plasma)

A

Fibrin clot/wall

274
Q

What are the special factors?

A

Cell-mediated Immunity

Antibodies and Complement

275
Q

Antigen stimulates the release of biologically active substances called lymphokines. Lymphokines enhance phagocytosis and killing

A

Cell-mediated immunity

276
Q

What is it called when an antibody combines with bacterial cells and makes them more susceptible to phagocytosis?

A

Opsonin

277
Q

What assists the antibody in neutralizing or lysing the bacteria?

A

Complement

Microbiology-1 (5 decks)

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