Micro Exam 4

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1

Focal infection:

local infection spreads to multiple sites

2

Sepsis:

systemic infection of the bloodstream

3

Subclinical infection:

Microbe present, but no apparent illness Individuals may be carriers, able to pass infection to others but showing no symptoms themselves

4

What is symbiosis?

The living together of two different organisms or populations

5

commensalism

A symbiotic relationship in which two organisms live in association and one is benefited while the other is neither benefited nor harmed,

6

mutualism

A type of symbiosis in which both organisms or populations are benefited.

7

parasitism

A symbiotic relationship in which one organism (the parasite) exploits another (the host) without providing any benefit in return.

8

What is normal microbiota?

microbes that natural colonize on/in your body. Not harmful

9

When does colonization begin?

begins at birth

10

Why are microbiota beneficial to us?

1-compete for attachment and nutrient (microbial antagonism)
2-produce bacteriocins that inhibit growth of other bacteria,
3-lower pH, inhibiting pathogen growth,
4-stimulate-shape immue system

11

What kind of things can change the normal microbiota?

diet, health, lifestyle, hygiene, stress, climate, occupation, emotional state, pH, temperature, sunlight, O2 and CO2, salinity, chafes over time, health, medication, host defenses

12

What is transient microbiota?

present for days, weeks, or months and then gone

13

What parts of the body would you expect to have populations of normal microbiota?

Skin, eyes, nose and throat, respiratory system, mouth, Digestive system (Large Intestine), Urinary system, Reproductive system.

14

What is the Human Microbiome Project? What is the purpose?

Develop reference set of microbial genomes Understand human microbiomes role in health and disease
Coordinated center for data and research

15

pathology

Study of disease

16

etiology

The study of the cause of a disease

17

pathogenesis

The development of disease

18

infection

Colonization of the body by pathogens (doesn’t always cause disease)

19

disease

an abnormal state in which the body is not functioning normally

20

Symtoms v Signs

Symptoms - Subjective changes in body function
Signs - Objective, measurable, observable changes

21

Local infection:

confined to a single area

22

Systemic infection

spread throughout the body

23

Sepsis:

systemic infection of the bloodstream

24

Focal infection:

local infection spreads to multiple sites

25

Subclinical infection:

Microbe present, but no apparent illness Individuals may be carriers, able to pass infection to others but showing no symptoms themselves

26

Primary infection:

Initial infection in previously healthy individual

27

Secondary infection:

acquired after primary infection Opportunistic pathogen exploits weakening caused by primary infection

28

Opportunisitic:

Normal microbiota in places not normally found Or in compromised patient

29

Syndrome

group of symptoms or signs that accompany a particular disease

30

Communicable disease

a disease that is spread from one host to another

31

Contagious disease:

a disease that is EASILY spread from one host to another

32

Noncommunicable disease

a disease that is not transmitted from one host to another

33

Why can’t Koch’s postulates always be used to determine the cause of a disease? What are some examples?

More than one organism can present with similar signs and symptoms
Nephritis, pneumonia

Some pathogens cause several disease conditions 
M. tuberculosis, Streptococcus pyogenes

34

Stage of Disease

card image
35

Acute disease:

Disease Symptoms develop rapidly, lasts a short time

36

Chronic disease:

Disease develops slowly, continues or recurs for a long time

37

What are reservoirs of infection?

A continual source of infection,

38

What are zoonoses?

disease that occurs primarily in wild and domestic animals but
can be transmitted to humans.

39

What are examples of nonliving reservoirs?

Soil, Water

40

What are the main kinds of contact transmission?

Direct Contact
Indirect Contact
Droplet Transmission

41

Fomite:

nonliving object that can spread infection,

42

vehicle transmission:

transmission of a pathogen by an inanimate reservoir

(Water-borne, Food-Borne, Air-Borne)

43

What is the difference between droplet transmission and air-borne?

Droplet less than 1 meter, doesn’t stay suspended, Airborne greater than 1 Meter, remain airborne for hours.

44

What is a vector?

carries disease-causing organisms from one host to another

45

What kind of organisms are vectors usually?

Arthropods

46

What is the difference between mechanical and biological vector transmission?

Mechanical - passive (fly w/ shit on feet)
Biological – active (Mosquito)

47

nosocomial infections:

infection that develops during a hospital stay and was not present at the time the patient was admitted; infection associated with any health care facility

48

epidemiology:

the science that studies when and where diseases occur and how they are transmitted.

49

incidence

The incidence of disease is the number of new cases occurring in a population over a defined time interval

tells how fast the disease is occurring in a population, a measure of risk
- # of new cases in a population during a specific time/ # of persons at risk of developing the disease during a time period

50

prevalence

the fraction of a population having a specific disease at a given time,
viewed as a slice through a population to see who has the disease and who doesn’t
- # of affected persons present in the population at a specific time/ # in the population at that time

51

Annual Mortality Rate

- total # of deaths from a cause in 1 year/ # of persons in the population at midyear

52

morbidity

incidence of a specific disease

53

mortality

number of deaths from a specific notifiable disease,

54

Snow

Mapped the occurrence of cholera in London

55

Nightingale

Showed that improved sanitation decreased the incidence of epidemic typhus

56

Semmelweiss

Showed that handwashing decreased the incidence of puerperal fever

57

sporadic:

disease that occurs occasionally in a population.

58

endemic:

disease constantly present in a population

59

epidemic:

disease acquired by many hosts in a given area in a short time

60

pandemic disease:

worldwide epidemic

61

Koch's postulates are the essential foundation for:

the steps that relate a specific microbe to a specific disease (etiology)

62

What is the general term for observable changes in cells that occur as a result of viral infection?

cytopathic effects

63

Which of the following is a possible location for a bacterial adhesion?

fimbriae
flagella
pili

All of the Above

64

Which of the following virulence factors is specifically involved in helping an organism to physically spread throughout the body?

hyaluronidase

65

You conduct a Limulus amebocyte lysate (LAL) assay on a sample of fluid that should be sterile. The result is positive! What does this indicate?

Endotoxin is present.

66

Some organisms are capable of orchestrating alterations that are collectively termed antigenic variation. This allows the organism to __________.

evade the host's immune system

67

True or False A-B toxins are PROTIENS

TRUE

68

True or False: In some cases, viral infections may cause cells to lose contact inhibition

TRUE

69

What cell wall component that contributes to invasiveness?

M protein

70

The symptoms of protozoan diseases are usually due to __________.

metabolic waste products

71

Hepatitis B virus transmitted by a finger-stick device enters the host via which portal of entry?

parenteral

72

Which type of organism produces the toxin responsible for paralytic shellfish poisoning?

an alga

73

True or False:
Microbes are more likely to enter the body through the skin than through the mucous membranes.

False

74

True or False:
Although some pathogens cause disease after entering the body via food and water consumption, many such microbes are killed by chemicals involved in the digestive process.

True

75

True or False:
The same disease symptoms result, regardless of how a particular microbe enters the body.

False

76

True or False:
If bacteria A and B have LD50 values of 109 and 1010, respectively, more cells of A than B will be needed to kill the host.

False

77

True or False:
If bacteria attach to host tissue, they will cause disease.

False

78

True or False:
Adhesin molecules can vary in structure among strains of a given bacterial species.

True

79

True or False:
The glycocalyx (capsule/slime layer) can affect bacterial virulence by allowing attachment and by hindering phagocytosis.

True

80

True or False:
Most host damage resulting from bacterial infection is the result of direct damage by the microbe.

False

81

True or False:
Patient symptoms may worsen after antibiotic treatment of infections caused by gram-negative bacteria due to the sudden release of endotoxins.

True

82

True or False:
Accumulations of viral proteins and nucleic acids inside infected host cells are called inclusion bodies.

True

83

The dose of microbes required to produce a measurable infection in half of the animals tested is referred to by the abbreviated term __________.

ID50

84

Infections acquired by bites, cuts, wounds, punctures, or surgery occur via the __________ route.

parenteral

85

__________ are bacterial enzymes that lyse erythrocytes.

hemolysins

86

Fibrin clots can be dissolved by enzymes called __________.

kinases

fibrinolysin

streptokinase

staphylokinase

kinase

87

The scum that builds up on shower doors, the formation of dental plaque on teeth, and the algae growth on the walls of swimming pools are all examples of __________.

biofilms

88

__________ are toxins modified to retain their ability to induce antibody formation but lose their toxicity.

toxoids

89

Toxins that stimulate proliferation of T cells nonspecifically and provoke intense immune responses are called __________.

superantigens

90

__________ are molecules on bacterial cell surfaces that enable them to adhere to the surface of host cells.

adhesins

ligands

91

The release of endotoxins as bacteria are destroyed by phagocytes causes the phagocytes to release tumor necrosis factor (TNF). The life-threatening loss of blood pressure occurring due to the action of TNF is called __________. (2 words)

endotoxic shock

septic shock

92

Lysogenic bacterial cells may express prophage DNA, causing them to take on different characteristics in a process referred to as __________.

lysogenic conversion

93

Saxitoxin is produced by ________.

fungi

94

pathogenicity:

the ability of a microorganism to cause disease by overcoming the defenses of a host

95

virulence:

the degree of pathogenicity of a microorganism.

96

What is the ID50? 

What conditions can affect the ID50

infectious dose for 50% of the population

can depend on portal of entry
depends on host environment

97

What are the main portals of entry?

Mucous membranes
Skin
Parenteral

98

How can the portal of entry affect the ID50?

Respiratory - sweep mucous out
GI - Hostile environment
Urinary - Urine flushing
Conjuctiva - tears

99

How do pathogens attach once they have gained entry?

Adhesions, Ligands

100

adhesins:

carbohydrate-specific binding protein that projects from prokaryotic cells; used for adherence, also called a ligand.

101

ligands:

carbohydrate-specific binding protein that projects from prokaryotic cells; used for adherence, also called a adhesion

102

What do host cells have that help with adherence?

Surface receptors

Usually sugars
Different receptors vary in structure-different cells in same host can have different receptors
Altering adhesins and/or receptors may be a way to prevent infection.

103

How are biofilms involved in attachment? 
Why are they significant in infection?

Allow cells to stick to surfaces and each other. Protects them from ABx and disinfectants

104

What are some strategies pathogens use for invasion? 


Capsules
Cell wall components
Enzymes
Antigenic variation
Penetration into host cell cytoskeleton

105

How do capsules and cell wall components help with invasion?

Impairs phagocytosis by host

106

What does antigenic variation mean?

changes in surface antigens that occur in a microbial population.

107

What is antigenic drift and antigenic shift?

Antigenic drift A minor variation in the antigenic makeup of influenza viruses that occurs with time.

Antigenic shift A major genetic change in influenza viruses causing changes in H and N antigens.

108

How can pathogens disrupt the host cell cytoskeleton?

Actin-protein in cytoskeleton - can be used by microbes to penetrate host cell and move through and between cells.


Invasins - proteins produced by microbes to rearrange actin filaments.

109

What are the main ways pathogens damage host cells?

1. Using host’s nutrients
2. Direct damage in immediate vicinity of invasion
3. Producing toxins
4. Inducing hypersensitivity reactions

110

What are siderophores?
How do they cause damage? 

By what method is most damage done?

Bacterial iron-binding proteins

111

exotoxins:

protein toxin released from living, mostly gram-positive bacterial cells.

112

endotoxins:

part of the outer portion of the cell wall (lipid A) of most
gram- negative bacteria; released on destruction of the cell,

113

toxigenicity:

the capacity of a microorganism to produce a toxin,

114

Toxemia:

the presence of toxins in the blood,

115

antitoxins:

a specific antibody produced by the body in response to a bacterial exotoxin or its toxoid.

116

toxoids:

an inactivated toxin.

117

What are the different kinds of exotoxins?
Which do most bacteria produce?

AB, Superantigen, Membrane Disrupting

AB exotoxin most common

118

leukocidins:

substances produced by some bacteria that can destroy
neutrophils and macrophages,

119

hemolysins:

an enzyme that lyses red blood cells,

120

superantigen

antigen that activates many different T cells, thereby eliciting a large immune response.

121

Where do endotoxins come from?

A-Protein, gram negative cell wall

122

Why is the LD50 higher than with exotoxins?

Toxins are enzymes and can be used multiple times w/o being used up

123

What kind of body reactions are produced by endotoxins?

Not usually fever, usually specific, neurotoxin ect...

124

What are portals of exit?
Which are the most common?

Upper respiratory tract saliva from the oral cavity sneezing
coughing
Gastrointestinal tract
feces / diarrhea from the bowel vomitus
saliva
Blood
infected blood
Urogenital tract semen
vaginal secretions
infected urine
Skin and mucous membranes
discharges from infected skin lesions and infected wounds

125

Descriptive Epidemiology:

collection and analysis of data

126

Analytical Epidemiology:

comparison of a diseased group and a healthy group

127

Experimental Epidemiology:

controlled experiments

128


Invasins

proteins produced by microbes to rearrange actin filaments.

129

What roles did Ehrlich, Fleming, and Domagk play in the development of antimicrobial drugs?

Ehrlich - "magic bullet" (Salvarsan-) Tx - syphilis
Flemming - Penicillin - 1st true ABx
Domagk - Sulfonimides - Inhibit Folic Acid Synthesis by mimicking PABA (Static)

130

What is an antibiotic? What was the first true antibiotic? What was the first synthetic antimicrobial?

a substance made by one organisms that acts against another.

sulfonamide-Prontosil

131

Know the following terms: bacteriostatic, bacteriocidal, narrow and broad-spectrum antibiotics.

Bacteriostatic: Inhibits bacterial growth

Bacteriocidal: Kills bacteria

Narrow-spectrum antibiotics: Active against a limited number of organisms e.g. Penicillin- active primarily against gram- positive

Broad-spectrum antibiotics:Active against broad range of organisms Disadvantage-kill normal florae.g. Ampicillin- modified penicillin active against gram-negative bacteria as well as gram-positive

132

What does selective toxicity mean? Why is it important?

antimicrobial drugs must act within the host without damaging the host.

Lessen harm to host w/ Tx.

133

What are the 5 main modes of action of antimicrobial drugs? Which ones use the differences between prokaryotic and eukaryotic cells to target pathogens? How does penicillin work? How does chloramphenicol work? Which drugs are structural analogs of PABA?

1.) Cell Wall - PEN (Beta-lactam disrupts cell wall)
2.) Protein Synthesis (Chloramphenicol, binds to 50S, inhibits peptide bonde formation)
3.) Metabolite Synthesis (Sulfonamides)
4.) Plasma Membrane
5.) DNA replication

134

What about Mycobacterium provides a target for chemotherapy? What is the target of amphotericin B on fungal cells?

Mycolic Acid

fungal membranes contain ergosterol, not cholesterol

135

What are the major modes of action of antiviral drugs? Antiprotozoan? Antihelminth?

Antiviral - Nucleotide analogs, Interferons, Antiretrovirals

Antiprotozoan - DNA synthesis, Anaerobic metabolism

Antihelminth - ATP synthesis, Nutrient Absorption, Paralysis

136

What are the 4 modes of bacterial resistance to antimicrobial drugs? What is beta-lactamase? Where does it attack certain antibiotics?

1 - Blocking Entry
2 - Inactivation by enzymes
3 - Efflux of ABx
4 - Alteration of target

137

How can bacteria acquire resistance?

Transformation
Transduction
Conjugation

138

What do MIC and MBC mean? Why is important to know the MIC?

Minimum Inhibitory concentration (Minimum dose to stop growth for Tx)

Minimum bacterialcidal concentration

139

What does synergy and antagonism mean pertaining to chemotherapy?

Syn - 2 together better than sum of each sep

Antag - 2 together less than sum of each sep