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Flashcards in Gram positive pathogens (complete) Deck (182):
1

Are Staphylococcus normal flora

yes, but they can be opportunistic pathogens

2

What are the nine groups of Gram positive pathogens we study

1. Staphylococcus Aureus
2. Streptococcus Pyogenes (A)
3. Streptococcus pneumoniae
4. Bacillus Anthracis
5. Clostridium (perfringins, dificile, tetani, and botulinum)
6. Listeria monocytogenes
7. Corynebacterium diptheriae
8. propionibacterium acnes
9. Actinomyces species

3

Staphylococcus is motile or nonmotile?

non-motile

4

how does Staphylococcus interact with oxygen (anarobe, aerobe)

facultative aerobe

5

What does Staphylococcus look like under a microscope

cocci in irregular clusters (grapes)

6

What is the most common organism found on the skin

Staphylococcus epidermis

7

Where is Staphylococcus aureus typically carried in 30-50% of the healthy population

nose and perineum

8

How can you tell between Staphylococcus aureus and Staphylococcus epidermis

Staphylococcus Areus is
coagulase positive, mannitol positive
Staphylococcus Epidermis
coagulase negative, mannitol negative

9

which is more virulent Staphylococcus Aureus or Staphylococcus epidermis

Staphylococcus Aureus

10

How many bacteria are required for disease to result from a staph infection

only a few hundred bacteria

11

what are the three things about Staphylococcus that cause pathogenicity

1. It's ability to evade phagocytosis
2. Production of enzymes
3. production of toxins

12

What are the three categories of Staphylococcus diseases

Noninvasive disease
Cutaneous disease
Systemic disease

13

What is a non-invasive Staphylococcus disease

food poisoning that results from ingested food contaminated with enterotoxin

14

What are examples of cutaneous Staphylococcus disease

scalded skin syndrome
impetigo
folliculitis
furuncles

15

How does Staphylococcus defend itself against phagocytosis

Protein A
Bound Coagulase:

16

how does Protein A help Staphylococcus defend against phagocytosis

Protein A onthe bacterial surface binds antibodies by the Fc end. This inhibits opsonization and complement

17

how does bound coagulase help Staphylococcus defend against phagocytosis

converts blood protein fibrinogen into fibrin molecules, which make blood clots, the Staphylococcus hides from the phagocytes in the clots

18

What are the 5 enzymes created by Staphylococcus that attribute to its virulence

Cell-free coagulase
hyaluronidase
staphylokinase
lipases
B-lactamase

19

What does Cell-free coagulase do for Staphylococcus

triggers fibrin formation, which helps the Staphylococcus hide from phagocytes

20

What does hyaluronidase do for Staphylococcus

breaks down hyaluronic acid, which allows the bacteria to spread between cells

21

what does staphylokinase do for Staphylococcus

dissolves fibrin threads in blood clots, which allows Staphylococcus aureus to free itself from clots

22

what do lipases do for Staphylococcus

digests lipids, allows Staphylococcus to grow on the skins surface and in oil glands

23

what do B-lactamases do for Staphylococcus

Breaks down penicilins, makes them resistant to beta-lactams

24

What are the 4 toxins produced by Staphylococcus

Cytolytic toxins
exfoliative toxins
Toxic shock syndrome toxins
Enterotoxins

25

What are the two cytolytic toxins created by Staphylococcus and what do they do

alpha-toxins- pore forming toxins
PVL - beta pore forming toxin that lyses leukocytes

26

What do the exfoliative toxins of Staphylococcus cause

they cause the patients skin cells to separate from each other and slough off the body

27

What does the toxic shock syndrome toxin of Staphylococcus cause

it causes toxic shock syndrome, which is caused by the creation of a superantigen

28

What do enterotoxins of Staphylococcus cause

they stimulate intestinal muscle crampings, naseua, and intense vomiting (staph food poisoning)

29

Does Staphylococcus aureus cause food poisoning

yes

30

Does Staphylococcus cause colitis

yes

31

what is colitis (caused by Staphylococcus )

overgrown Staphylococcus aureus in the bowels (caused by broad-spectrum antibiotic treatment), when they produce enterotoxin B you get damage to intestinal mucosa, cramps, pain, diarrhea, and fever

32

What are the 4 skin diseases caused by Staphylococcus aureus

impetigo
furuncles (boils) (infected hair follicle)
Carbuncler (many boils)
Scalded skin syndrome

33

What are the 5 systemic diseases caused by Staphylococcus

Toxic shock syndrome
Bacteremia
Endocarditis
Pneumonia
Osteomyelitis

34

What causes Toxic shock syndrome

the TSS toxin (from Staphylococcus ) being absorbed into the blood, and being used as a superantigen, which causes T-cells to produce far too many cytokines

35

what are the symptoms of toxic shock syndrome

high fever, rash, vomiting, diarrhea
renal, liver, and blood involvement

36

What is bacteremia

bacteria in the blood

37

What is endocarditis

when bacteria attack the lining of the heart

38

what is pneumonia

inflammation of the lungs in which the alveoli and bronchioles become filled with water

39

what is osteomyelitis

inflammation of the bone marrow and surrounding bone

40

What is the drug of choice to treat staph infections

Methicilins

41

Are any Staphylococcus organisms resistant to methicilins? what are they called

yes, MRSA (methicilin resistant staph. aureus)

42

What is the drug used for MRSA

vancomycin

43

how are staph infections prevented

1. proper food prep and storage
2. hand antisepsis
3. proper cleansing of wounds, catheters, and needles

44

Which type of bacteria is tracked by phage typing

Staphylococcus

45

What is the arrangement of cocci in streptococcus

cocci arranged in pairs or chains

46

how does streptococcus interact with oxygen

aerotolerant anaerobes

47

What is the system of classification often used for streptococcus

lancefield classification

48

What are the two groups of streptococcus that are common pathogens of humans

Group A and Group B strep

49

What is used to determine the group of streptococcus organisms

the bacterias C antigens

50

What is the name for the only organism in Group A strep

streptococcus pyogenes

51

what does strep pyogenes cause on blood agar plates

it forms white colonies surrounded by beta-hemolysis on blood agar

52

What does strep pneumoniae cause on blood agar plates

it does alpha hemolysis

53

do pathogenic strains of streptococcus pyogenes often form capsules

yes

54

When do Group A strep generally cause disease

1. normal microbiota are depleted
2. large inoculum enable strep to establish themselves before antibodies are formed against them
3. specific immunity is impaired

55

What does protein M of streptococcus pyogenes do

it interferes with opsonization and lysis of the bacteria, and helps the bacteria attach to keratinocytes of the host

56

What does a hyaluronic acid capsule do for streptococcus pyogenes

it camoflages the bacteria

57

What are the enzymes produced by streptococcus pyogenes, and what do they do?

Streptokinases
Deoxynucleases
C5a
They facilitate the spreading of streptococcus through the tissues

58

What are the toxins released by streptococcus pyogenes and what do they do

they are pyrogenic toxins, and they induce macrophages and T-helper cells to release cytokines

59

What do streptolysins do

they lyse RBCs, WBCs and platelets

60

What are the 6 diseases caused by group A strep

1. Pharyngitis (strep throat)
2. Scarlet fever
3. Pyoderma (impetigo)
4. Erysipelas
5. streptococcal Toxic Shock syndrome
6. Necrotizing Fasciitis

61

Scarlet fever is caused by a toxin of streptococcus pyogenes, what else is caused by that toxin

puerperal sepsis (an infection of the uterus)

62

What is scarlet fever

a rash that begins on the chest and spreads across the body, it is caused by erythrogenic toxin

63

What is pyoderma (impetigo)

confined, pus-producing lesions, usually on the face, arms or legs

64

What is erysipelas

lymph node involvement with pain and inflammation (bright red face-mask shaped inflammation)

65

What is streptococcal toxic shock syndrome

bacteremia and severe multisystem infections

66

What is necrotizing fasciitis

Flesh eating strep
strep that spreads in the deep tissues along fascia, it destroys tissues including fat and muscle. 50% mortality

67

What are two post-streptococcal diseases? (poststreptococcal sequelae) and what cause them

Rheumatic fever and glomerulonephritis
cross reactive antibodies

68

Which age group is the most common carrier and infected by streptococcus pyogenes

Children 1-15

69

How is Group A strep transmitted

by respiratory droplets, direct and indirect contact

70

How is Group A strep diagnosed

hemolysis, bacitracin sensitivity, gram morphology, catalase tests

71

What is used to treat Group A Strep

penicilliin G

72

how is group A strep prevented and controlled

isolation, early and complete treatment

73

What is the other name for the alpha-hemolytic streptococci

the viridans group

74

Where are the viridans group of streptococci normally found

the mouth, pharynx, GI tract, genital tract, and urinary tract

75

Which group of strep play a significant role in dental caries, and dental plaque production

Alpha-hemolytic Streptococci (The viridans group)

76

What can the alpha-hemolytic strep (viridans group) cause when they enter the blood

meningitis, and endocarditis

77

Which group of Strep mostly forms pairs of cocci

streptococcus pneumoniae

78

What happens when streptococcus pneumoniae is grown on blood agar? and then on blood agar in anaerobic conditions

it forms alpha-hemolytic colonies, then in anaerobic conditions it produces beta-hemolytic colonies

79

Where does streptococcus pneumoniae normally colonize

the mouoth and pharynx (pathogenic in the lungs)

80

What was the leading cause of human death before antibiotics

streptococcus pneumoniae

81

What percent of bacterial pneumonia is caused by streptococcus pneumoniae

60-70%

82

Which bacteria causes the majority of otitis media

streptococcus pneumoniae

83

in streptococcus pneumoniae, pathogenesis is tied to what

a large polysaccharide capsule

84

how does the polysaccharide capsule of streptococcus pneumoniae's polysaccharide capsule aid in pathogenicity

it binds factor H which inhibits the alternative complement pathway, and protects the bacteria from phagocytosis

85

What does the protein adhesin of streptococcus pneumoniae aid in its pathogenicity

it helps the cells bind to epithelial cells of the pharynx

86

What type of protease does streptococcus pneumoniae release

secretory IgA protease (destroys IgA)

87

What does the streptococcus pneumoniae toxin, pneumolysin do

a toxin released when the bacteria is lysed the lyses epithelial cells and suppresses digestion of the phagocytized bacteria

88

What are the 6 diseases caused by streptococcus pneumoniae

pneumococcal pneumonia
sinusitis
otitis media
bacteremia
endocarditis
pneumococcal meningitis

89

What is pneumococcal pneumonia

bacteria multiply in the alveoli, damaging it, and causing an inflammatory response

90

What is sinusits

streptococcus pneumoniae bacteria in the sinuses

91

what is otitis media

streptococcus pneumoniae bacteria in the middle ear

92

What is pneumococcal meningitis

when streptococcus pneumoniae bacteria spread to the meninges of the CNS

93

how is streptococcus pneumoniae diagnosed

gram stain of sputum smears, growth, optochin sensitivity, and bile solubility

94

How is streptococcus pneumoniae treated

penicillin or cephalosporins

95

how is streptococcus pneumoniae prevented

pneumovax 23 (adults)
pneumococcal conjugate vaccine (PCV) 7-valent

96

What is the structure of enterococcus

short chains or pairs without a capsule

97

where is enterococcus normally found

the human colon, rarely pathogenic here (pathogenic in the lungs, urinary tract, and blood)

98

What is enterococcus resistant against

B-lactams, sulfonamides, aminoglycosides, tetracyclines, and erthyromycins (some are even resistant to vancomycin)

99

What is VRE

Vancomycin resistant enterococcus

100

what is the structure of Bacillus

Bacilli that can occur singly, in pairs, or in chains

101

What makes bacillus particularly difficult to get rid of

it forms endospores

102

What is bacillus anthracis

Anthrax, a strict pathogen of humans and animals

103

How do humans contract bacillus anthracis

1. inhalation of spores
2. ingestion of spores
3. inoculation of spores into the body via a break in the skin

104

how long can anthrax spores survive

decades, possibly centuries

105

What is responsible for the virulence of anthrax

a 3 component toxin and a protein capsule

106

What are the two plasmids which house the virulence factors of anthrax

pXO1 and pXO2

107

What are the three forms of anthrax disease in humans

inhalation (pulmonary)
Gastrointestinal
Cutaneus

108

What is woolsorters disease

a pulmonary anthrax infection, induces capillary thrombosis and cardiovascular shock

109

How does one get gastrointestinal anthrax

ingestion of spore contaminated meat

110

What is a sign of cutaneus anthrax infections

Echar lesions (black, necrotic skin lesions)

111

how fatal are cutaneus anthrax infections

usually not fatal

112

how is bacilli diagnosed

large, non-motile, bacilli in the lungs or skin

113

how is bacilli anthracis treated

with ciproflaxin, penicilin, or tetracycline

114

how is bacilli anthracis prevented

control the disease in animals
vaccination (requires multiple doses and boosters)

115

besides bacilli anthracis, what are other important bacilli

bacilli cereus - food poisoning in rice, beans, and potatoes
Bacili subtilis - produces bacitracin

116

what produces bacitracin

bacilli subtilis

117

are clostridium bacteria aerobic or anaerobic

anaerobic

118

do clostridium bacteria produce endospores like bacillus

yes

119

Where are clostridium found

soil, water, and the GI tract of humans

120

What are the 4 different types of clostridium

clostridium perfringins
clostridium dificile
clostridium tetani
clostridium botulinum

121

what are the two main diseases caused by clostridium perfringins

food poisoning (enterotoxin)
Gas gangrene

122

how is gas gangrene caused by clostridium perfringins

endospores enter the tissues in a traumatic event, they germinate and cause necrosis,

123

what are the two toxins of clostridium perfringins that cause gas gangrene

lecithinase and pore-forming toxin
it is when there is necrosis that is accompanied by gas build up in the tissues

124

how is gas gangrene diagnosed

easily, just by its symptoms

125

how is gas gangrene treated

removing dead tissue, large doses of penicillin, and hyperbaric chamber

126

how is gas gangrene prevented

proper cleaning of wounds, but it is difficult to prevent because clostridium perfringins is so common in the environment

127

Where is clostridium dificile normally found

part of the intestinal microbiota

128

What leads to an infection of clostridium dificile

when patients are treated with broad spectrum antibiotic drugs

129

what are the two degrees of infections of clostridium dificile

minor = self-limiting explosive diarrhea
major = pseudomembranous colitis

130

what is pseudomembranous colitis

swollen colon that can perforate, leading to massive internal infection by fecal bacteria and death

131

how is a clostridium dificile infection treated

discontinuing antimicrobials, and restoring normal bowerl flora (fecal transplants)

132

What is botulism, and what bacteria is it caused by

botulism is flaccid paralysis, it is caused by clostridium botulinum

133

how does one contract botulism

by ingesting toxin from clostridium butulinum

134

why shoudn't infants younger than one consume honey

because it could contain the botulism toxin

135

What is the most potent poison known to man

botulism toxin

136

how is botulism treated

administration of the polyvalent antitoxin

137

how is botulism prevented

proper food preparation and storage (botulism toxin is destroyed by heat)

138

how does botulism cause flaccid paralysis

the toxin enters into a motor nerve terminus, and cleaves the SNARE proteins responsible for fusing the vesicle (containing ACH) with the terminal membrane. (doesn't allow the muscle to receive the neurotransmitter from the nerve)

139

What are the 3 forms of butulism

food-borne botulism
infant botulism
wound botulism

140

how is food borne botulism usually contracted

in home-canned food, or preserved fish

141

is infant botulism usually fatal

nope

142

how do the symptoms of wound botulism differ from that of food-borne botulism

they don't just the means of contraction

143

How is botulism diagnosed

the symptoms are diagnostic, confirmed by culturing the organism from food, feces or the wound

144

how is botulism treated

antibodies against the botulism toxin
antimicrobial drugs to kill clostridia in infant botulism

145

how is botulism prevented

proper canning of food
infants under 1 shouldn't have honey

146

how does clostridium tetani interact with air

it is an obligate anaerobe

147

where can clostridium tetani be found

soil, dust, GI tract of humans

148

When does tetanus result

when the bacterial endospores germinate and produce toxin

149

what are the symptoms of tetanus

spasms and contractions, death due to inability to exhale

150

Which bacteria causes lockjaw (spastic paralysis)

clostridium tetani

151

how is tetanus treated

cleaning of the wound to remove endospores, administration of antitoxin and antibiotics

152

how is tetanus prevented

vaccination TDaP, or Td

153

How does tetanus cause spastic paralysis

the tetanus toxin blocks the release of glycine, making it so the muscles can't relax

154

What is the hallmark of an anaerobic infection

foul odor

155

What is deceiving about the name of the anerobe bacteroides fragilis

it is actually one of the easiest anaerobes to grow

156

What is the most commonly isolated anaerobic bacterium, especially from the blood

bacteroides fragilis

157

What are the virulent features of bacteroides fragilis

- attachment pili
- polysaccharide capsule
- modified or absent lipid A
- enzymes

158

What makes listeria monocytogenes problematic

its ability to live within cells

159

What are the toxins and enzymes of listeria monocytogenes like

it doesn't produce any toxins or enzymes

160

Does listeria monocytogenes produce endospores

nope

161

how is listeria monocytogenes able to live inside cells, and move from one to another

it's able to live inside cells by its ability to escape from phagocytic vessicles. Then once inside cells it builds an actin tail (actin polymerization) which helps it propel itself through that cell and into others.

162

What is the thing that helps listeria monocytogenes escape from vesicles

LLO listeriolysin O - it is pore forming

163

What about the conditions that listeria monocytogenes can grow in is different from many other bacteria

it can grow at refrigerator temperatures

164

where do most infections of listeria monocytogenes in humans come from

contaminated milk or meat

165

What is the problem with a pregnant woman being infected with listeria monocytogenes

it can be transferred to the baby prenatally or postnatally, which can cause meningitis, and still-births

166

How is listeria monocytogenes treated, and prevented

it is treated with ampicillin, and it is prevented with pasteurization and proper cooking

167

how is a listeria monocytogenes infection diagnosed

presence of the bacteria in the blood or cerebrospinal fluid (gram staining isn't effective because so few cells are required to cause disease)

168

What is the name of the bacteria that causes diptheria

cornyebacterium diptheriae

169

how is diphtheria transmitted from person to person

respiratory droplets or skin contact

170

What are the signs and symptoms of diptheria

- pseudomembrane (dead cells and fluid that accumulates) in the respiratory tract, or on the skin (in the case of cutaneous diptheria)
- Bull neck (swelling in cervical lymph nodes)

171

Which bacteria can often be seen on a micrograph in V-shapes

cornyebacterium diptheriae

172

besides the respiratory tract, what else can diptheria toxin harm

the heart and CNS

173

how is diptheria diagnosed

clinical and serological tests

174

how is diptheria treated

antitoxin, then penicillin or erythromycin

175

how is diptheria prevented

toxoid vaccination

176

What is the bacteria that causes most of our acne

propionibacterium acnes

177

can propionibacterium acnes cause more than just acne

yes, it can also be an opportunistic pathogen

178

Why is actinomyces an important bacteria to study

because it is a major component of dental plaque and is associated with gingivitis and root caries

179

how is antinomyces treated

with amoxicillin

180

What is nocardia

a soil saprophyte that cause nocardiosis

181

what is nocardiosis

a TB-like pulmonary disease that can progress to form abscesses and can show on the back of the patient

182

What is streptomyces

a non-pathogenic bacteria that produces most of our antibiotics