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Micro > Lecture 3 and 4 > Flashcards

Lecture 3 and 4 Flashcards

1
Q

What is the bacterial iron binding protein?

A

Siderophore

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2
Q

What metal in humans is required by bacteria for electron transport?

A

Iron (Fe)

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3
Q

Describe generation curves of bacteria.

A

Peak is closer to higher temp range because enzymatic reactions occur faster with higher temp

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4
Q

What is the O2 metabolism of an aerotolerant microbe?

A

Don’t use O2 but not killed by it either

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5
Q

Define psychrophile, mesophile, thermophile, extreme thermophile.

A

Psychrophile - cold temps
Mesophile - like moderate temps; neither too hot/cold (15-45C)
Thermophile - like relatively high temps (40-70C)
Extreme thermophile - like high temps (70-100C)

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6
Q

What is the O2 metabolism of an microaerophile microbe?

A

Need O2, but O2 radicals are toxic

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7
Q

What happens in the lag phase?

A

Adapting to new nutrients

New enzyme synthesis - up-regulation

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8
Q

What is a persister cell?

A

dormant, non-dividing cell with slow metabolism

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9
Q

What happens in the exponential phase?

A

Growth and binary fision

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10
Q

What happens in the stationary phase?

A

Crowding, starvation or toxic conditions

New genes turned on to adapt to stress (usually toxins or virulence factor genes)

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11
Q

What happens in the decline phase?

A

Some cells lyse (maybe autolysis)

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12
Q

These cells cause a long, slow decline phase due to an asynchronous population…

A

Persister cells

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13
Q

What are autonomously replicating elements called?

A

Replicons

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14
Q

What is the difference between bacterial and viral chromosome?

A

Bacterial is usually circular, viral is circular or linear

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15
Q

A protein that binds upstream of promoter to allow transcription is called…

A

Activator

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16
Q

An environmental signal that turns ON genes no matter how is called…

A

Inducer

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17
Q

An environmental signal that turns OFF genes no matter how is called…

A

Repressor

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18
Q

What is the uptake of unpackaged/”naked” DNA?

A

Transformation

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19
Q

What are the 2 types of transformation?

A

Natural and induced
Cell must be competent to transform which is usually signaled by high cell numbers
Usually occurs when amino acids become limited

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20
Q

What are the importance of structural and regulatory associated proteins for bacterial chromosome?

A

Structural - anchors or bends DNA

Regulatory - turns genes on or off

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21
Q

Describe plasmids.

A

Circular, smaller than chromosomes, can exist in hundreds of copies, readily transferred by HGT

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22
Q

A protein that binds between promoter and gene to block transcription is called…

A

Repressor

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23
Q

What is natural plasmid transfer called?

A

Conjugation

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24
Q

Uptake of DNA by competence pheromones and use of quorum sensing is what kind of gene transfer?

A

Natural transformation

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25
Q

What is responsible for initiation of bacterial biofilms?

A

Quorum sensing

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26
Q

What is the main way bacteria can survive abx treatment?

A

Biofilm

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27
Q

How do F+ and F- cells interact?

A

F+ has genes for sex pili and F- has receptors for pili which allows them to attach

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28
Q

What is the importance of F-plasmids? (with respect to abx resistance)

A

F-plasmid gets integrated into the chromosome and can transfer adjacent chromosomal genes (possibly abx res. gene) by conjugation

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29
Q

What are R-plasmids?

A

Plasmids with multiple abx resistant genes

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30
Q

What is mefE?

A

Multiple drug efflux pump - can provide abx resistance by pumping abx out of cell

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31
Q

What is gene transfer by imprecise excision or packaging of phage called?

A

Transduction

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32
Q

What are the 2 types of transduction?

A

Generalized and specialized

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33
Q

How does generalized transduction work?

A

Random transfer of ANY gene that gets chopped up and put in a phage head

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34
Q

What phage cycle does generalized transduction use?

A

Lytic phage (one form of specialized)

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35
Q

What phage cycle does specialized transduction use?

A

Lysogenic phage (one form of specialized)

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36
Q

How does specialized transduction work?

A

Only genes near phage integration site can be transferred and the phage inserts into chromosome

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37
Q

Phage lysogens = Phage conversion… what is phage conversion?

A

phage carries gene for virulence factor from 1 bacteria to another

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38
Q

What is it called when transferred genes integrate into host chromosome to replace native genes?

A

Gene replacement

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39
Q

What is homologous recombination?

A

Recombination between same sequences

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40
Q

What is the result of an inverted repeat?

A

Inverted DNA sequence

41
Q

What is the result of direct repeats?

A

Deletion of a DNA sequence b/t repeats

42
Q

What are outer membrane vesicles?

A

Small vesicles that bud from outer membrane that contain genetic elements and signaling molecules (quoromones, toxins)

43
Q

Can outer membrane vesicles fuse with other cells and transfer cargo?

A

Yes

44
Q

Why are outer membrane vesicles important?

A

They can transmit pathogenic factors (toxins, abx resistant genes, virulence factors, quoromones)

45
Q

What organisms most commonly use outer membrane vesicles?

A

G- pathogens

46
Q

What are the benefits of E. coli, Oxalobacter, and gut microbiota?

A

E.coli - synthesized vit K
Oxalobacter - absorb excess oxalic acid
Gut - regulate TH17/Treg, interact c hormones for far reaching effect

47
Q

What is the relationship called when bacteria harm us (parasitism) then become commensal?

A

Balanced pathogenicity

48
Q

Inflammation is regulated by what T cell ratio?

A

TH17:Treg (gut bacteria balance this ratio)

49
Q

T/F: Skin organisms are hard to colonize, different for different sites (even fingers)?

A

T (hard because of low pH and NaCl)

50
Q

Important organisms in nasopharynx:

A

Normal:
1. diphtheroids - G+ club shape rods - Chinese
2. Staph epidermidis
3. Propionibacterium
Opportunists:
1. Strep pneumoniae - move into lungs = PNA
2. Neisseria meningitidis - gets released from attachments = meningitis
3. Hemophilus influenzae

51
Q

Imp organisms in mouth:

A
  1. alpha-hemolytic Strep (S. mutans)
  2. Staph epidermidis (and aureus)
  3. Pasteurellaceae - bites
  4. Actinomyces israelii
  5. Neisseria (important opportunist)
  6. GramNeg in tonsil area
52
Q

Important organisms in skin:

A
  1. Staph epidermidis (sometimes aureus) survive NaCl
  2. aerobic Corynebacterium (moist areas)
  3. Propionibacterium acnes - make butyric and propionic acids from lipids (sebaceous glands) - acne vulgaris
  4. G- org in moist areas
53
Q

What org causes “lumpy jaw”?

A

Actinomyces israelii

54
Q

What org serves as base layer on tooth surface for other bacteria to attach and grow?

A

Streptococcus mutans

55
Q

How does gingivitis increase risk of infection?

A

Makes the tissue more friable

56
Q

Imp organisms in stomach:

A
  1. Lactobacillus

2. H. pylori (~80% ulcers)

57
Q

Imp organisms in duodenum (low pH):

A
  1. Lactobacillus
58
Q

What 2 organisms cause vaginitis?

A

Gardnerella, Mycoplasma genitalium, lactobacillus

59
Q

What are 2 very common organisms in the GI tract?

A

Streptococcus, Staphylococcus

60
Q

Imp organisms in ileum-jejunum (higher pH)

A
  1. Enterobacteriaceae (facultative anaerobe)

2. Bacteroides (G- anaerobes)

61
Q

Imp organisms in colon (must all be anaerobes)

A
  1. Bacteroides
  2. Fusobacterium
  3. Clostridium
  4. Facultative enterobacteriaceae
62
Q

What are pre-op prophylactic abx?

A

neomycin/erythromycin + metronidazole (flagyl) - for anaerobes

63
Q

What are the 3 gut enterotypes?

A

Bacteroides (high fat/low fiber - carbs)
Prevotella (low fat/high fiber - glycopeptides)
Ruminococcus (most common)

64
Q

What are 4 enzymes that organisms use to get between cells?

A
  1. streptokinase-dissolves blood clots
  2. hyaluronidase-dissolves CT
  3. neuraminidase-Dissolves sialic acid glue
  4. collagenase-Destroys tissues
65
Q

Hijacking of host cell actin and the formation of fillapodia networks is generically referred to as…?

A

Membrane ruffling (listeria-internalin)

66
Q

Imp organisms in the vagina

A
  1. Lactobacillus
  2. Bacteroides
  3. Prevotella
  4. Finegoldia
  5. Gardnerella
  6. Mycoplasma genitalium
67
Q

What happens if there is too little Lactobacillus?

A

more vaginal infections

68
Q

Imp organisms in conjunctiva (most killed by lysozyme)

A
  1. Staph/Strep
  2. Hemophilus
  3. Neisseria
69
Q

Where are sterile areas (no native flora)?

A 
Lungs below trachea
Internal organs (except GI tract)
Fluids (blood, urine, lymph, semen)
CNS
Middle and Inner ear
70
Q

What are 3 adhesion factors?

A

Pili/fimbriae, adhesins, capsules/glycocalyces

71
Q

What is a type of adhesin?

A

G+ LTA

72
Q

What is a tissue tropism?

A

specific adhesion to certain tissues

73
Q

How to the halogens, Iodine and Chlorine, work?

A

Iodine - interferes with protein folding-can’t kill spores unless high concentration (betadine)
Chlorine - oxidizing agent (NaClO)-can’t kill spores unless high concentrations

74
Q

What is particularly useful for staph and strep?

A

Phenolics, Biguanides (chlorhexidine)

Phenolics toxic but still use for staph

75
Q

What mechanism do organisms taken up by non-professional phagocytic use to remodel the host’s cytoskeleton?

A

T3, T4, T6SS

76
Q

What organisms are best treated by cationic detergents?

A

G+

77
Q

What organisms use Ipas and Opas to promote engulfment by host cells?

A

Ipas - Shigella

Opas - Neisseria

78
Q

What 2 proteins are involved on the pathogen and host to cause phagocytosis?

A

PAMP (on bacteria), PRR (on host)

79
Q

What are 5 ways bacteria can avoid phagocytes?

A
  1. Prevent opsonization (by C3b complement)
  2. Antiphagocytic capsules (hide PAMP)
  3. M-protein and fimbriae
  4. LPS O-antigen variation or pili variation
  5. S. aureus protein A (attaches Ab backwards)
80
Q

What chemicals do bacteria use to kill phagocytes?

A

Leukocidins, Hemolysins, Anthrax, Pertussis toxins

81
Q

What are 5 ways for bacteria to deal with phagocytes?

A
  1. avoid them
  2. kill them
  3. prevent lysozomal fusion to phagocyte
  4. break out of phagolysozome
  5. resistance to lysozomal enzymes
82
Q

Do you get a fever and inflammation with exotoxin or endotoxin?

A

endotoxin

83
Q

What does antiseptic/disinfected mean?

A

Pathogens killed

84
Q

What does pasteurized mean?

A

Most pathogens killed

85
Q

What is the minimum inhibitory concentration (MIC)?

A

the minimum concentration which prevents bacteria from growing

86
Q

What is the difference between the Kierby Bauer test and the E test?

A

Kirby Bauer - Qualitative

E test - Quantitative

87
Q

What chemical class are high level sterilizers - kills spores?

A

Aldehydes

88
Q

What level allows spores and some naked viruses to survive?

A

Intermediate

89
Q

How do phenolics work?

A

denature proteins, dissolve membranes

90
Q

What is particularly useful for staph and strep?

A

Phenolics, Biguanides

91
Q

How do biguanides work?

A

damage cell membrane

92
Q

What is a powerful biguanide used for surgical scrub?

A

chlorhexidine

93
Q

Three examples of biofilms

A

Pseudomonas on skin
Stap epidermidis on catheters and implants
Strep mutans on teeth

94
Q

Ratio of what to what is seen more in asthmatics?

A

Asthma: proteobacteria
Normal: bacteroides

95
Q

Characteristics of exotoxin?

A 
Usually AB type
No fever
Often via PAI
Very toxic
Can make toxoid
96
Q

Characteristics of endotoxin?

A

Lipid A of LPS
GramNeg infections only
Fever via IL-1
Can’t make toxoid

97
Q

How does alcohol work as disinfectant

A

Denatures proteins
Dissolves membranes
Dries out cells
(can’t kill all viruses or spores)

98
Q

What is chlorhexidine limitation?

A

Spores

Micro (13 decks)

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