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MICRB 265 > Topic 8: Microbes in Health and Disease > Flashcards

Topic 8: Microbes in Health and Disease Flashcards

1
Q

________ _______ is a collection of microbes living in/on us.

A

Human microbiota

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2
Q

________ _______ is the microbiota and the environment(s) they live in.

A

Human microbiome

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3
Q

“_________ ______” is often used in basically the same way as microbiota.

A

Microbial flora

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4
Q

_________ is a term used to describe an altered microbiota that is unhealthy for the host.
- Typically thought of as being “out of balance” - loss of important commensals, increase in microbes associated with disease.

A

Dysbiosis

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5
Q

______ _______(16S) is a way to study microbiome

A

DNA sequencing

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6
Q

There are “big picture” similarities in microbiota of different people (similarities at phylum level), but the microbiome composition in each individual is ________ (very different at species level)

A

unique

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7
Q

Microbiota composition is more about _________ factors than genetic factors, but there are some genetic component.

A

environmental

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8
Q

Microbiota (esp. in gut) is established at young age and is remarkably resilient.
What does remarkably resilient mean?

A

Microbiota changes with different conditions but generally returns to original composition.

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9
Q

Resilience is important in microbiota. Loss of resilience can lead to ________

A

dysbiosis

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10
Q

Where are the microbes in/on our bodies?

A
  • gastrointestinal tract (stomach, small intestine, large intestine, colon
  • skin
  • oral cavity/upper respiratory tract (mouth, nose, throat, etc)
  • urogenital tract (vagina)
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11
Q

Our microbiome varies by _______.
e.g. different parts of skin or GI tract have very different community compositions

A

location

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12
Q

__________ _______ (organ) has very dense population of microbes

A

large intestine

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13
Q

Epithelium that lines intestines is protected by ________ layer.

A

mucus

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14
Q

____ is a thick and slippery suspension that includes antimicrobial factors and mucin (gel-like glycoprotein substance, serves a barrier function)

A

Mucus

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15
Q

Most microbes remain in the ______ of the intestine, they don’t directly contact host cells

A

lumen

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16
Q

There is ______ in the human gut microbiota.

A

variation

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17
Q

__________ are Gram-negative bacteria
- Masters of complex carbohydrate metabolism

A

Bacteroidetes

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18
Q

_________ is a very diverse phylum of Gram-positive bacteria

A

Firmicutes

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19
Q

__________ are generally facultative anaerobes- rapidly consume any oxygen present.
- Important for maintaining anaerobic environment
- High proportions of this can be a sign of dysbiosis.

A

Proteobacteria

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20
Q

_________ _______ (many species, but especially Bacteroidetes) can break down (ferment) diverse carbohydrates from food (or mucin)

A

primary fermenters

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21
Q

Main metabolism in the gut

A

Fermentation

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22
Q

Importance of gut microbiota for human health?

A
  • compete with potential pathogens - prevent/inhibit colonization
  • digest food for us. (e.g. ferment fiber to short-chain fatty acids that we then absorb)
  • produce nutrients that we can’t make (amino acids, vitamins)- get absorbed in the colon
  • promote a healthy immune system and promote immune tolerance
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23
Q

What do you call the relationship of humans and normal gut flora?

A

Mutualistic

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24
Q

What is an example of a relatively well established causal relationship in gut microbiome?

A

Helicobacter pylori in stomach appears to be the cause of stomach ulcers.

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25
Q

There are a lot of ________ on teeth (dental plaque)

A

biofilms

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26
Q

TRUE or FALSE
Although dental hygiene is important, it is normal and healthy to have a vibrant oral microbiome.

A

TRUE

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27
Q

Example of opportunistic pathogens in the skin

A

Staphylococcus aureus

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28
Q

Cuts/wounds in skin can lead to __________ (organism) infections
Many strains of this are antibiotic resistant which is a significant health issue.

A

S. aureus

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29
Q

S. aureus produces a number of ______ ________ ____ - bloodstream infections can be life-threatening

A

potent virulence factors

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30
Q

This species dominate the vaginal microbiota

A

Lactobacillus

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31
Q

_________ benefit host by lowering vaginal pH (~5) via fermentation end products (lactic acid) - helps prevent infection by pathogens.

A

Lactobacilli

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32
Q

Yeast (e.g. genus _______) are a part of the vaginal healthy microbiome, but found at low levels.
Disruption of microbiome (reduced Lactobacilli=increase pH) allows these yeast to bloom, leading to yeast infection

A

Candida

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33
Q

_________ are live microorganism(s) that, when administered, have a beneficial affect on host.
Consuming “good bacteria”

A

Probiotic

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34
Q

Some studies suggest that most commercial probiotics have _________ therapeutic value for most people.

A

limited

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35
Q

________ is a substance that when consumed promotes the growth of beneficial microbes.
Can be simple and effective
(e.g. fiber in diet to promote healthy microbiota)

A

Prebiotic

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36
Q

______ _______: fecal matter from health donor transplanted into a patient.
This is an attempt to reintroduce a normal/healthy microbiota into a patient experiencing dysbiosis causing significant health issue.

A

Fecal transplants

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37
Q

Probiotics are effective. Particularly to cure ______ ____ infections, which are highly resistant to antibiotics.

A

Clostridoides difficile

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38
Q

Microbial pathogens - ___________ are a major issue for plants as well.

A

phytopathogens

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39
Q

Fungal pathogens are probably a larger problem with plants than ______ pathogens.

A

bacterial

40
Q

Fusarium oxysporum, a fungal pathogen, causes _________ disease.

A

Panama

41
Q

Two types of trees that are wiped off due to fungal pathogens

A
  • chestnut tree
  • american elm
  • dutch elm
42
Q

________: invasion of body by a disease-causing organism.
- Can be asymptomatic, can result in different disease

A

Infection

43
Q

________: damage or injury to host organism.
Often results from infection but it is not the same.

A

Disease

44
Q

S. Typhi infections often cause a disease called _______ ______

A

typhoid fever

45
Q

_________: an organism that causes disease

A

Pathogen

46
Q

__________: mechanism that leads to disease

A

Pathogenesis

47
Q

_________: similar to pathogenesis, but often used to describe the severity of the disease (“highly virulent”) or whether or not an organism can cause disease

A

Virulence

48
Q

________ ________: organism that is often non-pathogenic, but becomes a pathogen under certain circumstances (e.g. access to an open wound or an immunocompromised host)

A

Opportunistic pathogen

49
Q

________ is the body’s immune response to infection or injury
Important part of how we clear infections.

A

Inflammation

50
Q

____________ individuals with weakened immune response are subject to greater risk of infection, more difficulty clearing infections.

A

Immunocompromised

51
Q

Some symptoms of bacterial diseases can come from activities of ________ (e.g. toxins, tissue damage)

A

pathogen

52
Q

Other symptoms of bacterial diseases are caused by our _______ ______ to the pathogen
(fever, rashes, redness, swelling)

A

immune response

53
Q

__________ _________ can have effects from mild to life-threatening.

A

Excessive inflammation

54
Q

Common stages in infections/microbial diseases

  • ________: Binding to specific host cells/tissues - get a foothold
  • _________: Expanding population- planktonic or biofilm
  • __________: Gain access to privileged sites - penetrate mucous membranes.
  • _________: Moving beyond site of initial infection. Uncontrolled systemic spread (via bloodstream) often results in very serious infections/disease
A

Adherence
Colonization
Invasion
Spread

55
Q

_______ ________ are tightly packed epithelial cell layers covered with a mucous layer. Important protective layer.
- Line common body access points (airways, oral cavity, GI tract) and are common places where infections are initiated.

A

Mucous membranes

56
Q

_________ is the ability of pathogen to enter host cells and/or tissues.
Penetrate beyond where microbes normally reside.

A

Invasion

57
Q

Some strategies of invasion of pathogen:

A
  • entering host cells
  • damage epithelial layer
58
Q

Example of an invasion strategy by a pathogen.

______ secretes an enzyme called hyaluronidase that degrades ______ acid, a polysaccharide that acts as a “cement” to connect some types of host cells.
This enzyme can disrupt epithelial layer to facilitate invasion.

A

S. pyogenes
hyaluronic

59
Q

_______ ________ are molecules (typically proteins) produced by a pathogen that contribute to its ability to cause disease.

A

Virulence factor

60
Q

Common types/activities of virulence factors: (5)

A
  • Adhesion factors
  • Nutrient acquisition (e.g. siderophores, secreted molecules that capture iron form the environment)
  • Immune resistance: Factors that help pathogen survive immune defenses (e.g. resistance to reactive oxygen species)
  • Immune evasion/disruption: Factors that hide microbe from immune system or that disrupt function of immune system
  • Extracellular enzymes, protein secretion systems/ effectors & toxins: Damage host cells and/or manipulate host cell biology
61
Q

Microbes generally target specific cell or tissue type
______ to specific receptors on those cells is often key to establishing infection

A

adhering

62
Q

________ provides a foothold, facilitates interactions with host cells, invasion of host cell or tissue.

A

Adherence

63
Q

Many types/categorizations of adherence factors “adhesins” are (4)

A
  • pili
  • fimbriae
  • surface proteins
  • capsules
64
Q

Adhesins often recognize specific receptors such as ________ or ________

A

glycoprotein or glycolipids

65
Q

_______ _____ means hiding from the immune system.

A

Immune evasion

66
Q

Many ways that pathogens evade the immune system:

A
  • hide inside cells (intracellular pathogens)
  • produce a capsule that hides surface antigens (preventing immune detection) & can inhibit uptake and destruction by immune cells.

-LPS detected by immune system-trigger immune response

  • toxins, secreted enzymes, secretion systems
67
Q

Secreted/surface enzymes can promote virulence in ways such as: (4)

A
  • Freeing up nutrients
  • Damaging host cells
  • Inactivating immune cell mechanisms
  • Disrupting barrier to enable pathogen invasion/spread
68
Q

Examples of secreted enzyme virulence factors that affect blood clotting

S. aureus secretes _________, which indices clots to prevent immune detection.

S. pyogenes secretes _______, which dissolves clots, enabling this pathogen to spread.

A

coagulase
streptokinase

69
Q

Several important pathogens produce ____ _____ secretion systems as key virulence factors (similar to T6SS but target host)
- Contact host cells, inject specific effector proteins into host cell via this secretion system

A

Type III (T3SS)

70
Q

T3SS ______ _______ have very specific targets (often a specific protein) in host cell.
Manipulate host cell biology in their favor.
e.g. effector inactivates a key host signaling protein- this ultimately enables bacteria attached to a host cell to enter this cell.

A

effector proteins

71
Q

Different effectors often have _________ activities.

A

complementary

72
Q

Some pathogens also use the _____ ____ secretion systems as virulence factors (L. pneumophila)

A

Type IV

73
Q

What is one limit of type III secretion systems?

A

You have to be in physical contact

74
Q

_______(“toxins”) are secreted protein toxins.
Similar to bacteriocins but they target the host.
This is amongst the most important virulence factors

A

Exotoxins

75
Q

Example of a bacterial toxin
effects: cell lysis, signaling changes

A

a-toxin from Staphylococcus aureus

76
Q

In an AB-type toxins,
___ subunit exerts biological effect, ___ subunit(s) bind host cell receptor (usually glycoprotein/glycoprotein) to mediate uptake.

A

A, B

77
Q

Botulinum toxin is produced by ________ _______
Rarely infects (adult) humans.
However, it grows/produces toxin on foods we consume.

A

Clostridium botulinum

77
Q

Example of an AB-type toxin

A

Botulinum toxin

78
Q

In an AB-type toxin, the “___ subunit” targets toxin to motor neurons.

A

B

79
Q

“A subunit” is a _______ that cleaves specific SNARE proteins that are required by these cells to release the neurotransmitter ________.
Absence of this neurotransmitter leads to muscle paralysis.

A

protease
acetylcholine

80
Q

______ is an example of a toxin used in clinics.
- used to treat range of diseases (migraines, cerebral palsy, painful muscle spasms) …. in addition to bunny lines.

A

Botox (botulinum toxin)

81
Q

An importance difference between toxins and secretion systems

A

Toxins can diffuse and spread to distant cells/tissues.

82
Q

Another difference between toxins and secretion systems

  • _____ often (not always) more potent; lone wolves. ________ often more nuanced, work together.
A

Toxins, Effectors

83
Q

A relatively minor problem today, _______ has arguably had amore substantial impact on human society than any other infectious disease.
- Caused by Yersinia pestis, a Gram-negative Proteobacterium

A

plague

84
Q

When and where was the most sever plague occurred?
Name of the plague

A

“the black death”
Eurasia
peaked from 1347-1351
Killed >50 million people

85
Q

Three types of plague all caused by Yersinia pestis:

All three have high mortality rates if untreated

A
  1. Bubonic plague
  2. Pneumonic plague
  3. Septicemic plague
86
Q

In this type of plague, there is an infection of lymph nodes
MOst common

A

Bubonic plague

87
Q

In this type of plague, there is an infection of lungs

A

Pneumonic plague

88
Q

In this type of plague, it infects the bloodstream

A

Septicemic plague

89
Q

Yersinia pestis evolved from _____ ________ within last 5,000-10,000 years.
They have virulence factors that allow them to infect/survive/transmit efficiently in the flea

A

Yersinia pseudotuberculosis

90
Q

_______ _______ ______ is a phospholipase D (cleaves phospholipids) that appears to detoxify an unknown substance in the flea gut.

A

Yersinia murine toxin

91
Q

_________ is the main virulence of Yersinia pestis due to ability to survive/subvert the immune system.
- hide from the immune system, go undetected until it’s too late.

A

Pathogenesis

92
Q

What are some major virulence factors (4)

A
  • F1 capsule
  • Pla
  • T3SS
  • Gene loss
93
Q

This is a virulence factor that inhibits uptake of Y. pestis by immune system & detection of surface antigens.

A

F1 capsule

94
Q

This virulence factor is a protease in the outer membrane.
Cleaves various host factors- a range of effects

A

Pla

95
Q

This virulence factor secretes a handful of important/potent effector proteins that disrupt immune system function

A

T3SS

96
Q

Example of gene loss is the loss of _______.
This is efficiently detected by immune system and the loss contributes to stealth.

A

flagellum

MICRB 265 (7 decks)

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