exam 1 Flashcards

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1
Q

what shape is bacillus

A

rod

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2
Q

what shape is coccus

A

spheres/ round

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3
Q

what shape is spirochete

A

flexible, thin, spiral-shaped rod

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4
Q

what shape is spirillum

A

rigid, spiral-shaped rod

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5
Q

what are pleomorphic bacteria

A

no defined shape, variety of shapes in one species

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6
Q

what is diplo

A

pair

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7
Q

what is strepto

A

chain

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8
Q

what is staphylo

A

grape-like cluster

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9
Q

what is tetrads

A

packets of 4 cells

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10
Q

what is sarcina

A

packet of 8 cells

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11
Q

what are the three main types of cell walls that bacteria have

A

gram-negative
gram positive
acid-fast

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12
Q

what are the main components common to all three cell wall types of bacteria

A

peptidoglycan
lipoprotein
(provide structure support)

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13
Q

what is the peptidoglycan layer made up of?

A

backbone
tetra peptide side chains
peptide cross-bridge

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14
Q

what are the antimicrobial enzymes found in secretions and granules of peripheral mononuclear cells? and what is their function?

A

lysozymes
-weakens the cell integrity

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15
Q

do gram positive bacteria have a thick or thin peptidoglycan layer

A

thick

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16
Q

do gram negative bacteria have a thick or thin peptidoglycan layer?

A

thin

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17
Q

what is the primary stain

A

crystal violet

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18
Q

what is the counterstain

A

safranin

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19
Q

what color are gram negative cells

A

they retain the counter stain so they are red

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20
Q

what color are the gram positive cells

A

they retain the primary stain and stain purple

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21
Q

what is the periplasmic space

A

space between the inner and outer membrane

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22
Q

what is a distinct component of the outer layer of gram negative cells

A

lipopolysaccharides (LPS)

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23
Q

LPS is also known as

A

endotoxin

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24
Q

what structures is the LPS composed of

A

O antigen
core polysaccharide
lipid A

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25
Q

what does the O antigen serve a purpose for in the LPS

A

serves as attachment sites

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26
Q

what does the lipid A serve a purpose for in the LPS

A

virulence factor of LPS
-this is the part responsible for the endotoxic activity

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27
Q

what are the two key components unique to gram positive bacteria

A

teichoic acid (WTA)
lipoteichoic acid (LTA)

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28
Q

what is the function of WTA/LTA in gram positive cells

A

allow for adherence of bacterial cells to host cells

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29
Q

what does teichoic acid adhere to

A

peptidogylcan

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30
Q

what does lipoteichoic acid adhere to

A

anchors to cell membrane

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31
Q

when an host is infected with a gram negative bacteria cell what can WTA/LTA initiate

A

WTA/LTA along with peptidoglycan can initiate endotoxin-like activities when released upon bacterial lysis
-but not truly an endotoxic reaction

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32
Q

what are structures that are unique to the acid-fast bacteria cell wall

A

mycotic acid layer (outer)
tetrameric porins

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33
Q

what is the function of mycolic acid layer of acid-fast bacteria

A

waxy coat
-provide resistance to desiccation, some antibiotics and inhibits phagocytosis

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34
Q

what are the two clinically relevant genera that are acid fast

A

mycobacterium
nocardia

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35
Q

what is the primary stain for acid-fast bacteria

A

carbolfuchsin
(acid-fast=red)

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36
Q

what is the counterstain for acid-fast bacteria

A

methylene blue (nonacid-fast=blue)

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37
Q

what is the point of the hot plate for an acid fast stain

A

to open that waxy coat to allow the stain to penetrate the cell to color

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38
Q

a foal was diagnosed with endotoxemia caused by endotoxins released into the bloodstream. the bacterial cell wall structure causing the patient’s symptom is what?

A

lipid A

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39
Q

a stained tracheal mucus specimen was collected from a cattle shows acid-fast bacilli. what genera should be included in your differential diagnosis?

A

mycobacterium

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40
Q

what are two forms of glycocalyx

A

slime layer
capsule

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41
Q

what is the function of glycocalyx

A

-promotes adherence of bacteria to surfaces to biofilm formation
-protects against desiccation
-acts as barrier to toxic hydrophobic molecules- antibiotics
-inhibits phagocytosis

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42
Q

function of slime layer of glycocalyx

A

protects bacteria cells from environmental dangers such as antibiotics and desiccation

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43
Q

what is the test quelling reaction used for

A

to determine whether bacteria have a capsule or not

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44
Q

describe how the quelling reaction works

A

antigen-antibody reaction causes a change in the refractive index of the capsule so that it appears “swollen” and more visible

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45
Q

what are the three major components of flagellum

A

filament
hook
basal body (anchor flagellum in cell membrane)

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46
Q

what protofilaments are each flagellum made up of?

A

composed of flagellin (H antigens)
-highly antigenic

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47
Q

what are the two main classes of pili

A

-ordinary/common pili
-sex pilus/conjugated pilus/F pilus

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48
Q

what does ribosome consist of

A

mRNA
protein

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49
Q

what are bacterial ribosomes made up of

A

50S and 30S subunits

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50
Q

ribosomes are important and are good for antimicrobial activity

A

:)

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51
Q

importance of inclusion bodies (internal structure)

A

various granules, vesicles and vacuole within cytoplasm
-can aid in identification of some bacteria

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52
Q

properties if endospores

A

core
spore wall
cortex
coat
exosporium

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53
Q

sporulation vs vegetative growth

A

-vegetative growth: a single endospore will create two daughter cells
-sporulation: go through process to make a spore coat and then a spore and the spore then gets activated from resting stage once there is lack of nutrients or something

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54
Q

two clinically relevant genera that produce endospores

A

bacillus
clostridium

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55
Q

what pH are transport media and culture media buffered at

A

~7.0

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56
Q

explain oxygen requirement for facultative anaerobes

A

no oxygen requires but will used if there is any available

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57
Q

do aerotolerant anaerobes require oxygen

A

no oxygen required and can tolerate some oxygen because it has reactive oxygen species (ROS), which knock out other reactive oxygen

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58
Q

what type of bacteria are capnophiles and where do they commonly reside

A

microaerophiles
-cheek/mouth is favorable area bc requires some CO2

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59
Q

what is an example of species that resist desiccation

A

staphylococcus spp

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60
Q

what is an example of species that can desiccation and needs transport media

A

haemophilus

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61
Q

what bacteria do not require NaCl but can grow under saline conditions (increase osmotic pressure)

A

halotolerant bacteria

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62
Q

what are chemohetertrophs

A

using organic compounds as sources of energy and carbon

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63
Q

what are fastidious bacteria

A

requiring additional organic compounds in their culture media (vitamins, aa)

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64
Q

what are solid media used for

A

isolation of pure cultures (agars)
-estimate the number of viable bacteria in a sample
-colony characterization can be used for microbial ID

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65
Q

what is a colony

A

population of cells arising from a single cell or spore, or from a group of cells of the same species or strain

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66
Q

what are liquid media (broths) used for

A

ideal for growing large numbers of bacteria (can’t actually visually determine number of species present)

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67
Q

what are semi-solid agars used for

A

determining motility, growing microaerophiles, some transport media

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68
Q

*agar is a solidifying agent, NOT a nutrient

A

man said its gonna be on exam

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69
Q

what is basal media and what are some types

A

sustain growth of less fastidious bacteria
-nutrient agar, nutrient broth, tryptic soy agar

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70
Q

what is enriched media and what are some types

A

basal media + additional nutrients (eg blood, egg yolk) used to cultivate fastidious organisms
-blood agar, chocolate agar

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71
Q

what is selective media and what are some types

A

reagents (dyes, NaCl) added that inhibit the growth of unwanted bacteria while allowing the growth of others
-MacConkey agar, mannitol salt agar
-so like selecting for gram + over gram - (give a favorable environment for the thing you are looking for)

72
Q

what is a differential (indicator) media and what are some types

A

contain component (dyes, pH indicators) that allow the differentiation of closely related taxa based on apprearance (color) of the colony or surrounding media
-MacConkey agar, mannitol salt agar, blood agar

73
Q

why would you not want nutrients in a transport media

A

some bacteria will overgrow and outcompete the other microbes and that will distort the ratio of microbes that are in there or prevent you from isolating the microbe that may be the causative agent of the problem being dealt with

74
Q

how would you grow rickettsia spp an obligate intracellular bacteria

A

-grown in animal cells

75
Q

how would you grow an extracellular bacterial pathogen such as mycobacterium leprae

A

best grown in a host organism

76
Q

what is a pure culture

A

contains only 1 species (or strain) of microbe

77
Q

what are the goals of preservation of maintaining a pure culture

A

viability
purity
genetic stability

78
Q

preservation techniques if bacterial cultures

A

-subculture of growing cells
-snap-freeze in broth w cry-preservative
-freezr-dry cells suspended in lyophilization medium

79
Q

generation time

A

time required for population to double

80
Q

after the decline phase of bacteria growth, what can some bacteria enter

A

a longterm stationary phase that can last for years

81
Q

when growth on a solid media is occurring what phase are the cells in center at

A

-cells at center are at stationary phase (zero population growth, near death)
-where as the cells on the edge are going through exponential growth

82
Q

pathogenicity

A

the ability of microbe to damage a host

83
Q

virulence

A

the relative capacity of a microbe to cause damage in a shot

84
Q

infectivity

A

the capacity of a microbe to become established in a host

85
Q

virulence factors

A

traits that confer pathogenicity (e.g. toxins)

85
Q

genes coding for virulence factors

A

-generally expressed facultatively
-unevenly distributed among strains of a species
-often spread by horizontal gene transfer
-often clustered into pathogenicity island

86
Q

what do adhesions bind to

A

complementary receptor molecules found on target host cells/tissues
-highly specific
-receptor-ligand interaction

87
Q

what does adhesion attachment specificity help bring about

A

-tissue tropism
-host specificity

87
Q

what does lipid A stimulate

A

systemic inflammatory response

88
Q

what are the 3 main portals of entry

A

GI
respiratory
urogenital

89
Q

what does the chemical siderophore that bacteria has on board do?

A

used to steal iron from iron-binding proteins

90
Q

biolfilms facilitate quorum sensing which allows what

A

allows biofilm inhabitants to coordinate their cellular activities (e.g. exotoxin production)

91
Q

what do the enzymes invasins do

A

local damage to host cell and ECM
-spread beyond colonization sites

92
Q

how can invasion of epithelia barriers be breached?

A

-parcellular route (between epithelial cells)
-trancellualr route (through the epithelial cells)

93
Q

4 ways pathogens damage hosts

A

-use host nutrients
-cause direct damage near colonization site
-produce toxins tha damdge sites distant from invasion site
-pathogens cause collateral dandle due to host inflammation or immune reactions

94
Q

subclinical (inapparent) infection

A

does not cause any noticeable illness

95
Q

what are the 4 types of carriers

A

passive
incubatory
convalescent
active

96
Q

what is a mutant

A

-offspring of a “normal” member of a species
-genetically distinct from “wild type” in some way

97
Q

isogenic strains

A

two lineages of the same bacterium that have a single change

98
Q

does the use of antibiotics create mutations that lead to resistance?

A

-mutations occur naturally
-adding antibiotics select for mutations that already exist in the body

99
Q

selection mutation

A

a growth condition that allows for growth of only a specific kind of mutant

100
Q

spontaneous mutations

A

occurring by inserting of incorrect base during replication

101
Q

induced mutation

A

addition of external factors (mutagens) that later chemical bonds in DNA and need repair

102
Q

what are the three types of mutations

A

-silent or synonymous mutations
-missense or non synonymous mutations (change of aa)
-null mutation (loss of function)

103
Q

does a nonsynomymous mutation always lead to a change in phenotype?

A

it depends on what is being mutated, where the amino acid is, and other factors

104
Q

what is prokaryotic polycistronic

A

multiple genes (protein coding sequences) on one mRNA

105
Q

what is eukaryotic monocistronic

A

one gene (one protein coding sequence) on a mRNA

106
Q

transcription termination in bacteria

A

-use factor dependent (Rho) and that binds to rut sites on mRNA molecules and it follows and treads the mRNA through a pore/loop until its bumps into mRNA polymerase and bumps it off the DNA

107
Q

what are nonsense mutations

A

mutations that change from coding an amino acid to coding for a stop codon

108
Q

what is frameshift mutations

A

base deletions or additions that alter the reading frame of the mRNA

109
Q

horizontal gene transfer

A

moving large chunks of DNA, not from mother to daughter cells, but from amoungst species ( e.g. e coli to salmonella)

110
Q

what is vertical gene transfer

A

DNA replication provides daughter cell with copy of parental cell DNA

111
Q

natural competence

A

to take up DNA from the environment
-strephococcus pneumoniae
-neisseria gonorrhoeae
-haemophilus influenzae

112
Q

how does natural transformation/ competence occur in gram negative and positive cells

A

DNA uptake occurs by the translocation of ssDNA molecule into the cell

113
Q

what is quorum sensing

A

bacteria communication
relays number of cells in an environment based on a secreted protein or product

114
Q

what does the build up competence stimulating peptide CSP cause

A

quorum sensing leads to the induction of competence

115
Q

fratricide

A

killing of neighboring non-competence cells as source for DNA

116
Q

process of horizontal gene transfer

A

transformation
transduction
transposition
conjugation or mating

117
Q

what does transduction of bacteria used bacteriophage for

A

-bacteria viruses, injecting DNA into host cell
-specialized transduction, small amount of DNA into adjacent cell
-generalized transduction, transfusing phage

118
Q

spcialized transduction vs generalized transduction

A

-specilaized transduction is when bacteriophages transfer specific bacteria genes located near page DNA in bacterial chromosome
-generzalized transduction is when phages randomly package bacterial DNA and transfer it to another DNA cell

119
Q

lytic growth

A

phage replicates

120
Q

lysogenic growth

A

phage silently inserts into bacterial chromosome and be replicated by cell division
-prophage (or lysogen): lytic genes repressed viral DNA remains silent in host

121
Q

what is transposases

A

the enzyme that cuts DNA and allows transposons to insert
copy and paste

122
Q

composite vs noncomposite transposons

A

-composite are large transposable elements that a typically carry antibiotic resistance markers
-noncomposite have inverted repeats and resistance markers

123
Q

bacterial mating or conjugation

A

transfer of DNA from donor to recipient cell

124
Q

F plasmid is a self-transmissivle plasmid and encode tra genes

A

idk man

125
Q

tra two main functions of F plasmid

A

Dtr- DNA transfer and conjugal replication
Mpf- mating pair formation

126
Q

conjugal F plasmid transfer process

A

-mating pair established
-single strand of DNA transferred
-DNA replication occurs in both donor and recipient cell

127
Q

pathogenicity islands

A

horizontally acquired sections of bacterial chromosome that encode genes primarily associated with virulence

128
Q

germ theory of disease

A

proposing that microorganisms cause disease

129
Q

what was the first effective treatment for syphilis

A

arsphenamine (salvarsan)

130
Q

narrow spectrum antibiotics

A

effective against a limited number of bacteria

131
Q

broad spectrum antibiotics

A

effective against wider array of bacteria

132
Q

cons of broad spectrum agents

A

increased development of resistance, disruption of microbiome
-it clears out and makes room for more bacteria to form and the ones left over are the resistant ones will flourish in that environment

133
Q

bactericidal antibiotics do what

A

kills

134
Q

bacteriostatic antibiotics

A

inhibits growth and allows for the immune system to get rid of the bacteria
-this also allows the body to develop antibodies against the bacteria

135
Q

if you have an immunocomprosmied patient would you want to use a bactericidal or a bacteriostatic antibiotic

A

you would want to use a bactericidal because the patients wouldn’t have an functioning immune system to fight off the bacteria for bacteriostatic

136
Q

selective toxicity

A

antibiotic specific for bacteria and not host cells
-should not be toxic to host cells (make sure its not toxic to certain species)

137
Q

what properties are important for an effective antibiotic

A

-selectie toxicity
-soluble in body fluids
-toxicity not easily altered
-nonallergenic
-stability
-bacterial resistance not acquired
-resonable cost

138
Q

five classes of antibiotics

A

-inhibition of cell wall synthesis
-disruption of cell membrane function
-inhibition of protein synthesis
-inhibtioin of nucleic acid synthesis
-action as antimetabolites

139
Q

what does the antibiotic beta lactams target on the bacteria

A

they target enzyme responsible for making cross-link (block transcriptase enzyme)

140
Q

what does the antibiotic vancomycin target on bacteria

A

they target side chains which normally aid in cross-linking

141
Q

what does the antibiotic bacitracin target on bacteria

A

they target flipase enzyme

142
Q

cephalosporins and penecillin is what type of antibiotic

A

B-lactam

142
Q

the antibiotics that are inhibitors of cell wall synthesis, B-lactams, vancomycin, bacitracin are what type of antibiotics

A

bactericidal
-these are most effective

143
Q

mode of action for vancomycin antibiotic

A

glycopeptide antibiotic
-binds to end of the pentapeptide chains on NAM blocking the transglycosylation and transpeptidation steps of peptidoglycan

144
Q

mode of action for bacitracin

A

-topical for toxicity
-prevetns dephosphorylation of bactoprenol (lipid carrier), preventing assembly and transport of NAG-NAM
-carrier molecule

145
Q

mode of action for polymyxin antibiotic

A

-topical or ophthalmic use
-distrupts cell membrane
-acts as cationic detergent, disrupting membrane structure

146
Q

what type of antibiotic is amino glycoside and what is the mechanism of action

A

-30S ribosome subunit inhibitor
-irreversibly bind to to 30S subunit and block the initiation complex, causing misreading and premature release of mRNA from the ribosome, halts protein synthesis

147
Q

toxicity of ahminoglycosides

A

ototoxic and nephrotoxic to cats and dogs

147
Q

what type of antibiotic is tetracyclines and what is the mode of action

A

-30S ribosome subunit inhibitor
-binds to the 30S subunit to prevent attachment of the aminoacyl-tRNA to the RNA-ribosome complex

148
Q

what type of bacteria is amphenicol and what is the mode of action

A

-50S ribosome subunit inhibitor
-binds to the 50S subunit, inhibiting peptide transferase

149
Q

what is the chloramphenicol toxicity

A

-type of amphenicol
-toxic to human mitochondria, associated with aplastic anemia in humans and may cause reversible bone marrow suppression in animals, cannot use *chloramphenicol in food animals

150
Q

what type of antibiotic is macroliodes and what is the mode of action

A

-50S ribosome subunit inhibitors
-binds to the 50S subunit, blocking formation of the initiation complex and translocation

151
Q

what type of antibiotic is lincosamides and what is the mode of action

A

-50S ribosome subunit inhibitor
-binds to the 50S subunit, disrupts protein synthesis

152
Q

what are cautions of using lincosamides

A

-toxic to rabbits, guineas, and hamsters
-contrainidicated in horses and neonatal animals, oral administration is hazardous in animals

153
Q

what is the mode of action for streptogramins

A

bind to different sites on the 50S ribosomal subunit, inhibition of protein synthesis at different steps

154
Q

what is the mechanism of action of quinolones/ fluoroquinolones

A

-inhibitors of nuclei acid synthesis
-bind to inhibits DNA gyrase (topoisomerase II) and topoisomerase IV, preventing bacterial DNA from unwinding and duplicating

155
Q

what is the mechanism of action of rifamycins

A

-inhibtiors of nucleic acid synthesis
-inhibtis DNA-depenent RNA polymerase
-prevents transcription of messenger RNA (mRNA)

156
Q

what is the mechanism of action for metronidazole

A

covalently binds to DNA and chops it off, causing breaks

157
Q

mode of action for sulfonamides and diaminopyrimidines

A

interferes with folic acid synthesis (needed for DNA synthesis)
-action as antimetabolite

158
Q

sulfonamides are competitive inhibtiors what what

A

dihydropteroate synthetase

159
Q

trimethoprim inhibtis what enzyme

A

dihydrofolate reductase

160
Q
A
161
Q

what is antibacterial resistance

A

the ability of bacterium to survive and multiple in the presence of an antibiotic

162
Q

innate (intrinsic) resistance

A

innate ability if a bacterial species to resist the acidity if an antibiotic through its inherent structural or functional characteristics

163
Q

acquired (extrinsic) resistance

A

organism obtains the ability to resist the activity if an antibiotic to which it was previously susceptible

164
Q

what are the mechanisms of action to prevent actions of antibiotics

A

-preventing the antibiotic from reaching its target (1-3)
–modifying or bypassing the antibiotic target (4-5)

165
Q

how is bacteria able to reduce the ability of the antibiotic to enter the cell

A

antibiotics that are unable to gain access into the bacterial cell will not be able to reach their intended target so they do ti by altering porins in the cell wall

166
Q

how is bacteria able to expel the antibiotic out of the cell via efflux pumps

A

some bacteria possess membrane proteins that can export or pump out antibiotics as fast as they enter the cell which decreases antibiotic concentration inside the cell

167
Q

how is bacteria able to inactivate by modifying or degradation

A

some bacteria have enzymes that can degrade or modify an antibiotic structure
ex B-lactamases

168
Q

B-lactamase inhibitors

A

-used in combo with B-lactam antibiotic to extend the activity spectrum of the antibiotic
-function to inhibit the activity of B-lactamase

169
Q

how is bacteria able to modify antimicrobial target

A

bacteria have acquired mutations or modified structures that no longer are recognized

170
Q

how is bacteria able to bypass the antibiotic target

A

some bacteria have acquired a “new” enzyme that allows bypass of a metabolic pathway

171
Q

wise use of antibiotics

A

-prescribe antibiotics only for bacterial infection
-educate clients to compete course bc if not you didn’t eliminate all the bacteria and give those left a chance to flourish in that environment
-try to determine most appropriate antibiotic for the infection

172
Q
A