Module 9 part 1 Flashcards

Staph, Strep, and Neisseria

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1
Q

Which is catalase positive or negative: Staphylococcus and Streptococcus

A

Staph is cat positive and strep is cat negative

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2
Q

What is the alpha, beta, and gamma classification of Streptococcus

A

hemolysis on a blood agar plate: alpha is partial hemolysis, beta is complete hemolysis, and gamma is no hemolysis

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3
Q

What are Lancefield antigens?

A

A, B, C, D, E through S. Characteristics of the C carbohydrate

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4
Q

how many species of Strep are human pathogens?

A

5

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5
Q

What is the Group A Beta Hemolytic Streptococci (GAS)?

A

Strep pyogenes

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6
Q

what are the antigenic components of the Strep pyogenes cell wall?

A

C carbohydate and M protein

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7
Q

What is the major virulence factor for GAS?

A

M protein

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8
Q

What inhibits the activation of complement and protects GAS from phagocytosis?

A

M protein

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9
Q

What enzymes contribute to GAS pathogenicity?

A

Streptolysin O and S, pyrogenic exotoxin, and Streptokinase

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10
Q

What antigenic enzyme destroys RBCs and WBCs

A

Streptolysin O

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11
Q

What enzyme is the principal factor for beta-hemolysis?

A

Streptolysin S

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12
Q

what toxin is also known as erythrogenic toxin and causes scarlet fever and TSS?

A

pyrogenic exotoxin

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13
Q

What enzyme activates plasminogen to lyse fibrin clots?

A

Streptokinase

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14
Q

What helps diagnose strep in the throat?

A

culture and rapid antigen test

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15
Q

pustule on the extremity or face that breaks down after 4-6 days to form a thick crust

A

pyoderma

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16
Q

infection of the dermis

A

erysipelas

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17
Q

Treatment for strep infections

A

penicillin and clindamycin

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18
Q

How do penicillin and clindamycin treat Strep?

A

they inhibit the bacterial ribosome and shut down protein syntehsis of pyrogenic toxin and M protein

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19
Q

What disease caused by GAS is a delayed antibody mediated disease?

A

Rheumatic fever

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20
Q

What disease caused by GAS causes immune responses against M protein that can cross-react with heart tissue due to molecular mimicry?

A

Rheumatic fever

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21
Q

antibody mediated inflammatory disease of glomeruli that occurs about a week after regular strep infection, where antibody-antigen complexes depossit in kidneys and result in damage from complement and PMN

A

acute post-streptococcal glomerulonephritis

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22
Q

best antibiotic for GAS pharyngitis

A

penicillin

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23
Q

antibiotics used for GAS pharyngitis patients who are not compliant with oral meds or have family history of rheumatic fever

A

1st gen cephalosporins, erythromycin, and azithromycin

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24
Q

What is Group B beta-hemolytic Strep also known as?

A

Streptococcus agalactiae

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25
Q

What bacteria is most commonly associated with pregnant women and babies?

A

Group B Strep

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26
Q

3 bacteria most commonly associated with neonatal meningitis

A

E. coli, Listeria monocytogenes, and group B Strep

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27
Q

Strep mitis, salivarius, mutans, and anginosus are all part of what group?

A

Viridans

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28
Q

What group of Streptococci represent more than 30% of bacteria from the mouth?

A

Viridans

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29
Q

What hemolytic group are the viridans streptococci?

A

alpha-hemolytic

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30
Q

What are the 3 main types of infections resulting from viridans Strep?

A

dental infections (esp S. mutans), endocarditis (esp subacute bacterial endocarditis, SBE), and abscesses (anginosus group strep)

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31
Q

What 3 bacteria are causes of abscesses?

A

Anginosus group: S. intermedius, S. constellatus, and S. anginosus

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32
Q

How to remember which bacteria cause abscesses

A

Strep intermedius and anginosus- immediately assess for abscess

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33
Q

What bacteria can cause subacute bacterial endocarditis?

A

viridans strep, Staph aureus, and group D strep

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34
Q

2 subgroups of Group D strep

A

enterococcus and non-enterococcus

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35
Q

What are the enterococcal bacteria?

A

Enterococcus faecalis and E. faecium

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36
Q

What are the non-enterococcal bacteria?

A

Strep bovis and Strep equinus

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37
Q

What hemolytic group are enterococci

A

alpha or gamma

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38
Q

What bacteria are resistant to ampicillin plus aminoglycoside, and now also vanc?

A

Enterococci

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39
Q

50% of people with S. bovis bacteremia also have what?

A

colonic malignancy

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40
Q

What group of bacteria grow in bile but not salt?

A

non-enterococcal Group D strep

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41
Q

what do Strep pneumoniae look like?

A

diplococci

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42
Q

major virulence factor for Strep pneumoniae

A

polysaccharide capsule

43
Q

What are some other virulence factors for Strep pneumoniae?

A

capsule, pneumolysin, hydrogen peroxide, IgA1 protease, neruaminidase, adhesins

44
Q

How are Strep pneumoniae identified?

A

it’s alpha-hemolytic, sensitive to optochin (aka P disc), reactive under Quellung reaction, and lysed by bile acids

45
Q

Diseases caused by Strep pneumoniae

A

pneumococcal pneumonia, otitis media, sinusitis, bacterial meningitis

46
Q

3 major pathogenic Staph species

A

Staph aureus, epidermidis, and saprophyticus

47
Q

How to differentiate Staph and Strep

A

Staph are clustered while Strep is in chains. Staph are catalase positive. Culture is not always most helpful, but Staph aureus is beta hemolytic, golden on SBA, and coagulase positive

48
Q

what surrounds the peptidoglycan wall of Staph aureus

A

microcapsule

49
Q

Protein that binds the Fc portion of IgG and protects bacteria from opsonization

A

Protein A

50
Q

protein that leads to fibrin formation around bacteria and protects from phagocytosis

A

coagulase

51
Q

proteins that destroy red blood cells, neutrophils, macrophages, and platelets

A

hemolysins

52
Q

proteins that destroy leukocytes

A

leukocidins

53
Q

secreted form of beta-lactamase that disrupts the beta-lactam ring of penicillin

A

Penicillinase

54
Q

protein also called transpeptidase, and necessary for peptidoglycan formation

A

novel penicillin binding protein (PBP)

55
Q

protein that breaks down proteoglycans in connective tissue

A

hyaluronidase

56
Q

protein that lyses fibirin clots that’s released from Staph

A

staphylokinase

57
Q

protein that facilitates Staph aureus colonization in sebaceous glands

A

lipase

58
Q

diffusable exotoxin that causes skin to slough off (condition called scalded skin syndrome)

A

exofoliatin

59
Q

exotoxins that cause food poisoning

A

enterotoxins

60
Q

more deadly analogue to pyrogenic toxin from strep

A

Toxic shock syndrome toxin 1 (TSST-1)

61
Q

What are some diseases caused by exotoxin release from Staph aureus?

A

food poisoning, TSS, scalded skin syndrome

62
Q

What are some diseases caused by direct organ invasion of Staph aureus?

A

pneumonia, meningitis, osteomyelitis, acute bacterial endocarditis, septic arthritis, skin infection, bacteremia/sepsis, and UTIs

63
Q

sudden-onset/acute endocarditis results from what bacteria?

A

Staph aureus

64
Q

2 skin infections caused by Strep pyogenes and Staph aureus

A

cellulitis and impetigo

65
Q

folliculitis that penetrates into subcutaneous tissue

A

Furuncle

66
Q

Even worse version of a furuncle

A

carbuncle

67
Q

Common bacteria causing catheter infections

A

Staph aureus

68
Q

What do staphylococci secrete that makes them penicillin resistant?

A

penicillinase

69
Q

What gives Staph aureus methicillin resistance?

A

acquisition of a chromosomal DNA segment, mecA, that encodes for a new PBP 2A

70
Q

How does MRSA pass its resistance genes?

A

via transposons

71
Q

What treats MRSA?

A

Vanc

72
Q

What causes community acquired MRSA?

A

Panton-Valentine Leukocidin (PVL) toxin that causes skin abscesses

73
Q

What do VISA and VRSA stand for?

A

Vancomycin intermediate Staph aureus and Vanc resistant Staph aureus

74
Q

what indicates resistance of Staph aureus to all glycopeptide antibiotics?

A

VISA

75
Q

MIC for VISA

A

8-16 micrograms/mL

76
Q

MIC for VRSA

A

more than 32 micrograms/mL

77
Q

modified DNA transposon found in VRSA

A

vanA

78
Q

What bacteria is normally found on the body, responsible for biofilms on catheters, IVs, implants, and prostheses?

A

Staph epidermidis

79
Q

Difference in identifying Staph aureus vs epidermidis

A

Staph epidermidis is coagulase neg

80
Q

Second most common cause of UTIs in women

A

Staph saprophyticus

81
Q

Only pathogenic gram-neg cocci

A

Neisseria

82
Q

What do Neisseria look like?

A

diplococci, and each are shaped like kidney beans

83
Q

2 pathogenic species of Neisseria in humans

A

Neisseria meningitidis and gonorroheae

84
Q

virulence factors for Neisseria meningitidis

A

capsule, endotoxin (LOS), IgA1 protease, pili

85
Q

infectious serogroups of N. meningitidis

A

A, B, and C

86
Q

High risk groups for Neisseria meningitidis

A

infants 6 months to 2 years, army recruits, and college freshmen

87
Q

How does Neisseria meningitidis spread

A

via respiratory secretions from an asymptomatic person’s nose

88
Q

particular symptom special for meningococcemia

A

petechial rash

89
Q

Type of meningitis with septic shock, adrenal hemorrhage and insufficiency, rapid hypotension, tachycardia and petichiae

A

fulminant meningococcemia

90
Q

2 bacterai that cause meningitis later in life

A

Neisseria meningitidis and Haemophilus influenzae

91
Q

Classic medium for Neisseria culture

A

Thayer Martin VCN media

92
Q

What is Thayer Martin VCN media?

A

chocolate agar with antibotics: vancomycin, colistin (kills gram neg except neisseria) and Nystatin (kills fungi)

93
Q

treatment for meningococcus

A

Penicillin G or ceftriaxone

94
Q

second most commonly transmitted sexual infection

A

gonorrhoea

95
Q

Virulence factors for Neisseria gonorrhoeae

A

Pilus, outer membrane protein porins (PorA and PorB), Opa proteins

96
Q

symptoms of gonococcal disease in men

A

urethritis, epididymitis, prostatitis, urethral strictures

97
Q

treatment for gonorrhea

A

ceftriaxone

98
Q

symptoms of gonococcal disease in women

A

burning during urination and prurulent urethral discharge

99
Q

What can gonococcal infection progress to in women?

A

PID, including endometritis, salpingitis, and oophoritis

100
Q

complications of PID

A

sterility, ectopic pregnancy, abscesses, peritonitis, peri-hepatitis

101
Q

Symptoms of gonococcal infection in infants

A

opthalmia neonatorum (gonococcal conjunctivitis) which can damage the cornea and cause blindness

102
Q

How are neonatal gonorrhea and chlamydia eye infections treated?

A

erythromycin eye drops

103
Q

Treatment for gonococcal infections

A

Penicillin G and sulfonamides previously, now often ceftriaxone and single dose of azithromycin