Topics 10-29 Flashcards Preview

Vet. Bacteriology > Topics 10-29 > Flashcards

Flashcards in Topics 10-29 Deck (191)
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1
Q

What are the 3 types of thermal preference

A
  • psychrophilic
  • mesophilic
  • thermophilic
2
Q

What are the temperature ranges in psychrophilic Bb

A

<15°c

3
Q

Temp. for Mesophilic Bb

A

15-45°c

4
Q

Temp. for Thermophilic Bb

A

> 45°c

5
Q

How do Bb reproduce

A

binary fission

6
Q

How do Bb grow

A

-incr. in size and Vol.

7
Q

Name the phases of Bb propagation

A
  • lag phase
  • exponential (log) phase
  • stationary phase
  • regressive phase
8
Q

How can you count the total count of Bb

A
  • microscopic count (bürker chamber)
  • electronic cell count
  • spectrophotometry (turbidity)
  • flow cytometer
9
Q

How can you count the total live count of Bb (Cfu/ml)

A
  • broth dilution method
  • plate count
  • -spread plate
  • -pour plate
  • membrane filter
10
Q

What is a CFU

A

In microbiology, a colony-forming unit is used to estimate viable bacteria or fungal cells in a sample

11
Q

How can you maintain a Bb culture

A
  • on media
  • in the freezer
  • -@-18 - -80°c
  • lyophilisation
12
Q

How can we describe the environmental conditions for Bb propagation

A
  • optimal - fast replication
  • tolerable - decr. replication
  • non tolerable - no repl., Bb die
13
Q

How can one make the conditions non tolerable for Bb

A
  • drying
  • cooling, keeping warm
  • salting, addition of sugar
  • pickling
14
Q

How can we control Bb

A
  • physical agents

- chemical agetns

15
Q

Name physical agents used for controlling Bb

A
  • pasteurisation

- sterilisation

16
Q

Name chemical agents used for controlling Bb

A
  • disinfection

- antibiotics, antibacterial agents

17
Q

Bb are more susceptible to cold than heat T/F

A

F

18
Q

Bb are resistant to cold T/F

A

T

19
Q

Name some thermal sterilisation methods

A
  • dry heat: oven, flaming, incineration

- moist heat: autoclave, steaming, boiling

20
Q

Pasteuriasation

A

62-140°c for a certain period of time

the hotter the shorter time is necessary

21
Q

Mechanical pressure resistance of Bb

A
  • 5-6*10^7 Pa
22
Q

Even ultrasound can not damage the cytoplasmic membrane T/F

A

F

23
Q

Aim of disinfection

A
  • elimination of pathogens

- reduction of saprophytes

24
Q

Disinfection is a selective method T/F

A

F

25
Q

Name the criteria a disinfectant needs to fullfill (8)

A
  • broad spectrum
  • lack of toxicity, mutagenicity, carcinogenicity
  • non toxic to environment
  • good penetration
  • odourless
  • water soluble
  • non corrosive
  • low cost
26
Q

Activity of disinfectant is influenced by

A
  • resistance of Bb
  • number of Bb
  • Cc of disinfectant
  • temp.
  • time
  • pH
  • surface
27
Q

How is the activity of a disinfectant quantified

A
  • species killed
  • species inhibited
  • speed of inactivation
  • side effects
28
Q

Name the 2 types of disinfecting agents

A
  • disinfectants

- antiseptics

29
Q

What can you use disinfectants for

A

utensils, stables, vehicles..

30
Q

What can you use antiseptics for

A

skin, mucous membranes, tissues

31
Q

Name all the disinfectants (10)

A
  • Halogens
  • Aldehyes
  • oxidative agents
  • alcohols
  • detergents
  • phenol
  • acids, alkalis
  • salts
  • dyes
  • sterilising gases
32
Q

Name an example of a halogen

A

Cl2

33
Q

In what disinfectant can halogens be found

A

household bleach

34
Q

How do organic clorine compounds act

A
  • slow long release, stable
  • disinfection of hand
  • func. with oxidation
35
Q

Spectrum of organic iodine

A

bactericidal, fungicidal, sporocidal, virucidal

36
Q

Characterize aldehydes

A
  • highly reactive
  • use reduction, alkylation
  • wide spectrum
37
Q

Name some examples of Aldehyde disinfectants

A
  • Formaldehyde
  • -gas form too
  • -vaccine prod.
  • -toxic
  • Glutaraldehyde
38
Q

Name some oxidative agents

A
  • H2O2
  • -for wounds
  • -damage of cyoplasmic mem., DNA
  • urea hydrogen peroxide
  • peracetic acid
  • ozone
39
Q

All oxidative agents have a fairly wide spectrum T/F

A

T

40
Q

Characterise alcohols

A
  • activity correlates with chain length
  • water is needed
  • denaturate proteins
41
Q

Spectrum of alcohols

A

-bactericidal, virucidal

42
Q

Name the 2 parts of Detergents

A

hydrophilic hydrophobic

43
Q

Name the 4 groups of Detergents

A
  • anionic
  • cationic
  • amphoter
  • non ionic
44
Q

Anionic detergents

A
  • soaps, SDS

- no disinfecting ability

45
Q

Cationic detergents

A
  • react on lipids

- only bactericidal (G+mostly)

46
Q

Characterize phenol

A
  • good antibacterial activity
  • toxic
  • increased permeability
  • cell wall denat.
  • bactericidal, fungicidal
47
Q

Name some acid disinfectants

A

lactic acid, acetic acid, formic acid

48
Q

Mode of action of acids

A

coagulation of proteins

49
Q

Spectrum of acids

A

bactericidal fungicidal

50
Q

Name some salts used

A

Hg,Ag, Cu

51
Q

Spectrum of salts

A

bactericidal, fungicidal

52
Q

Name some disinfecting dyes

A

crystal violet, brilliant green, methylene blue, malachit green

53
Q

How do dyes work as disinfectants

A

enzyme inactivation

54
Q

Spectrum of dyes

A

bactericidal fungicidal

55
Q

Name some sterilising gases

A

ethylene oxide, propylene oxide, ß-propiolactone

56
Q

what are sterilising gases used for

A

sterilisation of heat sensitive material

57
Q

Spectrum of sterilising gases

A

sterilisation

58
Q

mode of action of salts

A

enzyme inactivation

59
Q

mode of action of phenol

A
  • denat. of proteins
  • incr. permeability
  • cell wall dead
60
Q

Mode of action of oxidative agents

A
  • oxidation nanednana

- - protein, DNA, cell wall lipids

61
Q

What are Antibiotics

A

microbial metabolites which can kill or inhibit growth of susceptible bacteria

62
Q

When was penicillin discovered

A

1929

63
Q

Who discovered Penicillin

A

Alexander fleming

64
Q

What does the use of AB depend on

A

their selective toxicity

65
Q

What must Abs exploit to make sure only their targeted Bb gets hurt

A

biochemical differences in structures and metabolic pathways of Bb and eukaryotic cells

66
Q

Antibacterial activity has to have…

A

.. narrow range but a broad spectrum

67
Q

What effects do Abs have

A
  • bacteriostatic

- bactericidal

68
Q

What do Bacteriostatic agents do

A

inhibit growth of Bb

69
Q

What do Bactericidal agents do

A

cause irreparable damage and Bb cell death

70
Q

Name some bacteriostatic agents

A
  • tetracycline
  • chloramphenicol
  • macrolides
  • sulfonamides
  • trimetoprim
  • nitrofurans
71
Q

Name some bactericidal agents

A
  • ß-lactam Abs
  • polypeptides
  • aminoglycosides
  • quinolones
  • bacitracin
  • vancomycin
72
Q

Name all the ways Abs can hurt Bb (7)

A
  • inhibition of cell wall synthesis
  • inhibition of cell membrane function
  • inhibition of protein synthesis
  • inhibition of DNA dependent RNA polymerase
  • inhibition of DNA gyrase
  • disruption of DNA structure
  • inhibition of DNA synthesis
73
Q

Name the cell wall inhibitors

A
  • Penicillin
  • Cephalosporins
  • Vancomycin
74
Q

How does Penicillin work

A

blocks peptidoglycane synthesis - inhibits cross linking

75
Q

Penicillin works only against Bb in the stationary phase T/F

A

F only against Bb in log phase

76
Q

How does Penicillin get excreted

A

via the kidney

77
Q

Which Bb does Penicillin work against

A

mainly Gr+ and some Gr-

78
Q

Which Bb are resistant to Penicillin

A

Bb with a thin peptiglycan layer and impermeable LPS

and beta lactamase test or lack of penicillin binding protein rec.

79
Q

How does Cephalosporin act

A

inhibition of transpeptidase enzymes (resp. of synth. pentapeptide units)

80
Q

Bb resistant against Cephalosporin have

A
  • structural advantages
  • modified binding sites
  • beta-lactamase enzymes
81
Q

Cephalosporin is active aminly against

A

Gr+ Bb

82
Q

Damagers of cell membrane

A

Polymyxins

83
Q

What do polymyxins have

A

a defined hydrophobic and hydrophilic part

84
Q

How do polymyxins work

A

they bind to cell membrane phospholipids - cause structural disorganization and permeability damage

85
Q

Whcih Bb do polymyxins attack

A

only Gr-

86
Q

Polymyxins can act only on multiplying cells T/F

A

F multiplying and stationary

87
Q

Name the 2 groups able of inhibiting protein synthesis

A

Aminoglycosides

Tetracyclines

88
Q

Name the Aminoglycosides

A
  • Streptomycin
  • Neomycin
  • Kanamycin
  • Gentamycin
89
Q

What do the protein synthesis inhibiting agents act on

A

30s

90
Q

What is 30S

A

prokaryotic small ribosomal subunit, subunit of 70S ribosome found in prokaryotes. is implicated in the binding of tRNA on mRNA The small subunit is responsible for binding and reading mRNA during translation

91
Q

What do the Aminoglycosides cause

A

Misreading of the mRNA by binding to the 30S ribosome and halting the 30S initiation complex

92
Q

What is the result of the Aminoglycoside action

A

-faulty proteins are produced

93
Q

against which Bb are the Aminoglycosides active

A

agaisnt Gr- Bb and myco Bb

94
Q

How can Bb be resistant against Aminoglycosides

A
  • binding site
  • anaerobic Bb (O2 requ. for uptake)
  • inactivating enzymes
  • ph - active in an alkaline environment
95
Q

what is MIC

A

minimum inhibitory concentration

96
Q

Name the Tetracyclines

A
  • Tetracycline
  • Oxytetracycline
  • Chlortetracycline
  • Doxycycline
97
Q

How do tetracyclines act

A

inhibition of binding of tRNA

98
Q

What do tetracyclines bind to

A

reversibly bind to the 30S ribosome and inhibit binding of aminoacyl-t-RNA to the acceptor site

99
Q

Name the groups whcih can inhibit Protein synthesis (50S)

A
  • Chloramphenicol
  • Macrolids
  • Lincosamides
100
Q

Name the Chloramphenicol group

A
  • Chloramphenicol
  • Thiamphenicol
  • Florfenicol
101
Q

What do Chloramphenicols inhibit

A

peptidyl transferase

102
Q

Name the Macrolids

A
  • Erythromycin
  • Oleandomycin
  • Tylosin
  • Tilmicosin
  • Tiamulin
103
Q

What do the macrolids inhibit

A

inhibition of binding tRNA to ribosomes

104
Q

Which agents can inhibit the superhelx of DNA

A

Quinolones

105
Q

Name some Quinolones

A

-nalidixic acid
-oxolinic acid
-flumequine

106
Q

What do Quinolones inhibit

A

-inhibit DNA gyrase (prevent coiling)

107
Q

How can Bb be resistant to Quinolones

A
  • transport
  • obligate anaerob.
  • mod. gyrase
108
Q

Which agents can inhibit RNA replication

A

Rifampins

109
Q

How do Rifampins act

A

inhibit DNA dep. RNA polymerase

110
Q

Which agents inhibit intermediate metabolism

A
  • Sulfonamides

- diaminopirimidines

111
Q

Sulfonamides and diaminopirimidines act how

A

interfere with biosynthesis of folic acid

112
Q

What agents produce metabolites against Bb DNA

A
  • Nitrofurans

- Nitroimidazoles

113
Q

What are the principles of antibiotic therapy

A
  • used on the basis of correct diagnosis
  • most effective antibiotic
  • correct dosage
  • correct treatment time
  • tissue concentration must exceed effective concentration in the site of infection
114
Q

Resistance to Ab occurs bc.

A
  • enzymatic drug inactivation
  • modification of binding sites
  • decr. IC accumulation
  • alteration in metabolism
115
Q

Name the types of resistance

A
  • Innate
  • Acquired
  • Cross resistance
  • Multiresistance
116
Q

What is innate resistance

A

chromosomally encoded , general physiology of Bb (e.g. cell wall structure)

117
Q

What is acquired resistance

A

can arise from a mutation or transfer of genetic material encoding resistance genes

118
Q

What is cross resistance

A

a single mechanism confers resistance to multiple antimicrobial agents

119
Q

How can antimicrobial susceptibility be tested in Bb

A
  • disc diffusion method
  • Broth dilution method
  • E-test
120
Q

Describe the disc diffusion test

A
  • prepare a uniform disk of Bb
  • put paper discs each with a different antimicrobial agent on the disk
  • check for zones of inhibition
121
Q

Factors affecting the size of the zone of inhibition

A
  • size of inoculum
  • test medium
  • antimicrobial agent and concentration
  • incubation condition
122
Q

How to evaluate the disc diffusion test

A
  • Susceptible if diameter is >20mm
  • moderately susceptible 15-20mm
  • resistand <15mm
123
Q

Broth dilution method is performed how

A

preparing a two fold dilution of an antibiotic in a series of tubes
each tube is inoculated with Bb and then incubated
measure turbidity

124
Q

How much cell volume does the DNA take up

A

10%

125
Q

How is the genetic material structured in Bb cells

A
  • Chromosome

- extrachromosomal genetic elements: Plasmids, Bacteriophages

126
Q

Possible forms of DNA

A

haploid, circular, double stranded

127
Q

Plasmids have single stranded DNA T/F

A

F double stranded

128
Q

Plasmids are relatively uniform in size T/F

A

F vary size

129
Q

Plasmids replicate independently from the chromosome T/F

A

T

130
Q

Name the number of plasmids in one cell

A

1-4 - 20-30

131
Q

Name the most important plasmids

A
  • F:fertility
  • R: antibiotic resistance
  • bacteriocins
  • Ent: enterotoxin prod.
  • Hly: haemolysin
  • Attachment (fimbria, capsule)
132
Q

What are Bacteriophages

A

viruses which infect bacteria

133
Q

Which kinds of DNA do Bacteriophages have

A
  • dsDNA
  • ssDNA
  • dsRNA
  • ssRNA
134
Q

Prophage

A

the DNA is integrated into the bacterial chromosome

135
Q

After the binary fission daughter cells are genetically identical T/F

A

T

136
Q

What is a Mutation

A

change in the base sequence of DNA

137
Q

Name the different kinds of mutations

A
  • spontatneous
  • induced
  • point
  • missense
  • nonsense
  • reversion
138
Q

What can mutations influence

A
  • cell structure
  • metabolism
  • resistance
  • virulence
139
Q

Name potential mutations influencing cell structure

A
  • colony morphology
  • cell wall synthesis
  • capsule formation
  • flagella formation
  • fimbria prod.
140
Q

Potential mutations influencing resistance

A
  • antibacterial drugs - mutation on the ribosome

- phage - mutation on binding site

141
Q

Mutations influencing virulence

A
  • toxin prod.
  • capsule form.
  • fimbria prod.
142
Q

What’s Transposition

A

translocation of DNA elements in the genome

143
Q

Name the 2 ways of Transposition

A
  • IS (insertion sequence) elements

- Transposons

144
Q

What are transposons

A

segments of DNA that can move from one region of DNA to another and integrate

145
Q

What are insertion sequences

A

800-1400 bp sequences without code function

146
Q

Where could a transposons be transfered to

A

from a chromosome to a plasmid for example

147
Q

What are Mutations, Recombinations, Transpositions

A

Genotypic variants

148
Q

What’s recombination

A

receiving new genes encoding new characteristics

149
Q

Name the forms of recombination

A
  • conjugation
  • transformation
  • transduction
  • phage conversion
150
Q

How is conjugation performed

A

DNA transfer between two Bb in contact with each other using sex fimbria

151
Q

What are the two parties in Conjugation called

A

donor and recipient cells

152
Q

What is the conjugation mediated by

A

the plasmid called F-Factor - fertility factor

153
Q

What is actually being transferred in Conjugation

A

the F-plasmid which copies itself OR parts of the chromosome

154
Q

How does the copied plasmid insert itself in the new genome

A

inserts itself on a specific site in the chromosome

155
Q

How does Transformation work

A

DNA is transferred as naked DNA - breaks - taken up - a piece of the received DNA is integrated - unused DNA is degraded

156
Q

What does competent mean in regard to Tranformation

A

competent cells let large DNA molecules pass their cell wall

157
Q

What is Transduction

A

DNA transaction by a bacteriophage

158
Q

2 forms of Transduction

A
  • generalized

- specialized

159
Q

How does generalized transduction work

A

Phage infects cell A - A DNA is incorporated in phage - Cell A lyses - phage infects cell B - DNA A becomes integrated in B

160
Q

Hoe does specialized transduction work

A

some phages can integrate into the host cell genome - gets excised - phage incorporates original cell genes and replicates - cell is lysed phages are released - infect new cell and incorporate into genome

161
Q

What are phenotypic variants

A

results of environmental effects

162
Q

What could phenotypic variants influence

A
  • morphology
  • resistance
  • enzyme prod.
163
Q

Phenotypic variations always only influence one cell T/F

A

F whole population can be affected

164
Q

How to examine the bacterial genome

A
  • GC ratio/content

- DNA fingerprinting

165
Q

What does DNA-DNA hybridization do

A

compares similarity between DNA sequences

166
Q

How to amplify DNA

A

PCR

167
Q

Genomes of bacteria are elastic

A

Genomes of bacteria are elastic meaning they often receive new genetic info. recombination can be beneficial neutral or harmful

168
Q

What is the difference between Sterilisation and Disinfection

A
  • Sterilisation= all bacteria, viruses, fungi, spores, parasites, prions are dead
  • disinfection= killing all pathogenic bacteria, and significant reduction of microbial flora
169
Q

Where to find saprophytes in a host

A

in a natural bacterium flora
in a symbiosis or mutualism
e.g: colon flora

170
Q

In what relationship are path. Bb with their host

A

Parasitism - fac. pathogens

predatory prey interaction - obgl. path.

171
Q

What’s the definition of pathogenicity

A

the ability of a microbe to damage a host

172
Q

Pathogenicity is qualitative concept T/F

A

T

173
Q

Virulence is a qulitative concept T/F

A

F quantitative concept

174
Q

What is Virulence in relation to pathogenicity

A

the degree of pathogenicity
amount of all factors of pathogenicity
connected to a bacterium strain

175
Q

How to measure virulence

A

in animal trials

only in target animal species !

176
Q

What parameters are used in animal trials

A

MLD (minimum lethal dose) /MID(minimum infective dose)
-death of all trial animals

LD50/ID50
-death of 50% of trial animals

177
Q

Virulence is not a constant feature T/F

A

T

178
Q

What can be an incr. in virulence

A
  • passage in the host species (selection of more virulent Bb)
  • recombination
  • -induced
  • -spontaneous
179
Q

What can be a decr. in virulence

A
  • mutation
  • spontaneus
  • passage
  • -maintanance in lab
180
Q

What are virulence factors

A
  • features involved in pathogenicity
  • morphological, metabolic, structural .. characteristics
  • different properties
181
Q

How can virulence factors be grouped

A
  • non toxic

- toxic

182
Q

Where could be cell wall associated virulence factors be found

A
  • capsule
  • adhesins
  • antiphagocytic materials
183
Q

Name capsule associated virulence factors

A
  • D-glutamic acid polypeptide
  • hyaluronic acid
  • polysaccharides
  • inhibits phagocytosis, protects Bb
  • better replication
184
Q

Name adhesins associated virulence factors

A
  • fimbria

- surface proteins

185
Q

Name antiphagocytic materials virulence factors

A
  • prevent the fusion of phagosoma and lysosoma
  • lipid complexes
  • mycolic acid, waxes
186
Q

Name all the extracellular enzymes (10)

A
  • coagulase
  • fibrinolysin
  • hyaluronidase
  • collagenase
  • lipase
  • lecitinase
  • deoxyribonuclease
  • urease
  • leucocidins
  • hemolysins
187
Q

Who can prod. exotoxins

A

Gr+ & Gr-

188
Q

Who can produce endotoxins

A

Gr-

189
Q

How are exotoxins released

A

excreted

190
Q

How are endotoxins released

A

cell lysis

191
Q

Endotoxins are more toxic than Exotoxins T/F

A

F