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COM MOD 2.2 Bacteria 1 > Chapter 1.4 Streptococci > Flashcards

Chapter 1.4 Streptococci Flashcards

1
Q

What type of bacteria is streptococci?

A

Gram-positive

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2
Q

What are the differences between streptococci and staphylococci?

A

Appearance

Enzymes

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3
Q

What is the appearance of Streptococci vs Staphylococci on a gram-stain?

A

Streptococci line up one after the other like a strip

Staphylococci appear as a cluster

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4
Q

What is the enzyme difference between Streptococci and Staphylococci?

A

Staphylococci have catalase whereas streptococci do not

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5
Q

How are the 3 groups of Stretococcci categorized?

A

By their specific hemolytic ability

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6
Q

What are the characteristics of beta-hemolytic streptococci?

A

They completely lyse the RBCs and leave a clear zone of hemolysis around the colony

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7
Q

What are the characteristics of alpha-hemolytic streptococci?

A

They only partially lyse the RBCs and leave a greenish discoloration of the culture surrounding the colony

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8
Q

What are the characteristics of gamma-hemolytic streptococci?

A

They are unable to lyse RBCs

*are non-hemolytic streptococci

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9
Q

What antigens help classify streptococci based on their antigenic characteristics?

A

Lancefield antigens- A, B, C, D, E –> S

*but only 5 are significant in human pathogens and 3 of them have Lancefield antigens (A, B, D)

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10
Q

What are the 2 human significant streptococci that do not have Lancefield antigens?

A

Stretococcus pneumoniae and Viridans group of streptococci

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11
Q

What categorizes a streptococci into Group A Streptococci?

A

Lancefield antigens A and beta-hemolytic

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12
Q

What is another name for group A streptococci?

A

Streptococcus pyogenes – which means pus-producing

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13
Q

What diseases are associated with streptococci pyogenes?

A

Strep throat, scarlet fever, rheumatic fever, and post-streptococcal glomerulonephritis

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14
Q

What are the antigenic components of the streptococcal cell?

A

C carbohydrate, M protein

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15
Q

What is the M-protein in the streptococcal cell wall?

A

Major virulence factor for group A Stretococcus

Inhibits activation of complement and protects against phagocytosis

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16
Q

What are the enzymes associated with group A streptococci?

A

Streptolysin O- oxygen labile- inactivation by oxygen and destroys red and white blood cells and is antigenic
Streptolysin S- oxygen stable- not antigenic
Pyrogenic exotoxin

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17
Q

What is the function of pyrogenic exotoxin in some group A streptococci?

A

Cause scarlet fever

Produce superantigens that super stimulate T cells to cause streptococcal toxic shock syndrome

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18
Q

What are the 4 types of disease by local invasion and/or exotoxin for group A streptococci?

A

Streptococcal pharyngitis, streptococcal skin infections, scarlet fever, and streptococcal toxic shock syndrome

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19
Q

What are the 2 delayed antibody mediated diseases of group A Streptococci?

A

Rheumatic fever and glomerulonephritis

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20
Q

What are the characteristics of streptococcal pharyngitis?

A 
Classic strep throat with red, swollen tonsils and pharynx
Purulent exudate from tonsils
High temperature
Swollen lymph nodes
Usually lasts 5 days
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21
Q

What are the characteristics of skin infections with group A streptococci?

A

Range from folliculitis (hair follicle infection), cellulitis (deep infection of skin cell), and impetigo (blistered eruption that becomes crusty and flaky)

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22
Q

What is the mechanism of necrotizing fasciitis in group A streptococci?

A

“Flesh-eating streptococcus”

They enter through a break in the skin caused by trauma and then follow a path along the fascia between the subcutaneous tissue and muscle

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23
Q

What are the manifestations of necrotizing fasciitis of group A streptococci?

A

A day later- Skin color changes from red to purple to blue, large blisters (bullae) form
Later- skin dies and muscle can become infected (myosotis)

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24
Q

What bacteria can cause necrotizing fasciitis?

A

Group A streptococcus, staphylococcus, clostridium, gram-negative enterics, or mixed infections with more than one of these

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25
Q

What are the characteristics of Scarlet fever by group A streptococci?

A

Production of exotoxin- pyrogenic toxin or erythrogenic toxin that produces fever and scarlet red rash

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26
Q

What is the pattern of the rash associated with Scarlet fever?

A

Starts on the trunk and neck and then spreads to the extremities, sparing the face

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27
Q

What are the characteristics of Streptococcal toxic shock syndrome caused by group A?

A

Release of pyrogenic toxin

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28
Q

What are the characteristics of rheumatic fever by group A streptococcus?

A

Usually affects children 5-15 years old

Joint swelling,

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29
Q

What is chorea?

A

Uncontrolled dance-like movements of the extremities in rheumatic fever

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30
Q

What is erythema marginatum?

A

Rash with a red margin that spreads from it’s center

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31
Q

What makes rheumatic fever antibody-mediated?

A

There are antigens in the heart that are similar to the antigens of group A streptococci therefore the antibodies that form eradicate cross-react with the antigens of the heart causing myocarditis

32
Q

What is the most frequently damaged site of the heart in rheumatic fever?

A

Mitral valve followed by the aortic valve

*occurs 10-20 years later

33
Q

What are the characteristics of acute post-Stretococcal glomerulonephritis?

A

Antibody-mediated inflammatory disease of the glomeruli of the kidney
Occurs 1 week after infection of either pharynx or skin group A streptococci

34
Q

What is the patient presentation of an individual with acute post-streptococcal glomerulonephritis?

A

Puffy face from fluid retention from damaged kidneys
Urine is darker than normal (tea or coca-cola colored) from hematuria
Patient may say they had sore throat or skin infection a week ago

35
Q

What is the name for group B streptococci?

A

Stretococcus agalatiae

*think B for Baby

36
Q

How can an individual acquire group b streptococci?

A

A baby can acquire it through vaginal delivery

37
Q

Who is susceptible to group B streptococci?

A

Neonates (

38
Q

What are the signs of meningitis in a neonate?

A

Nonspecific signs such as fever, vomiting, poor feeding, and irritability

39
Q

How can a diagnosis of meningitis be made?

A

Through lumbar puncture

40
Q

What organisms must be covered in antibiotic treatment for meningitis?

A

E. Coli, Listeria monocytogenes, and group B stretptococcus

41
Q

What bacteria are in the Viridans group of streptococci?

A

Streptococcus salivarius, S. Sanguis, S. Mitis, S. Intermedius, S. Mutans

42
Q

What are the characteristics of Viridans group streptococci?

A

Alpha-hemolytic

Normal GI tract flora that are found in nasopharynx and gingiva

43
Q

What are the 3 main types of infection from Viridans streptococci?

A

Dental infections, endocarditis, and abscesses

44
Q

How is dental infection caused by Viridans group streptococci?

A

The Viridans bind to the teeth and ferment sugar which produces acid and dental caries

45
Q

How is endocarditis caused by Viridans group streptococci?

A

Dental manipulation send showers of the organism into the bloodstream and they can implant on the endocardial surface of the heart

46
Q

Where on the heart is the most likely place where viridan group streptococci implant?

A

Damaged heart valve

47
Q

What is the specific result after Viridans implant on the heart?

A

Subacute bacterial endocarditis

48
Q

What are the characteristics of subacute bacterial endocarditis?

A

Slow growth and piling up of bacteria on the heart

49
Q

What is the patient presentation if they have subacute bacterial endocarditis?

A

Low-grade fever, fatigue, anemia, and heart murmur secondary to valve destruction

50
Q

What endocarditis is associated with staphylococcal infection?

A

Acute infective endocarditis

51
Q

How does acute infective endocarditis occur?

A

Staphylococcal infection secondary to IV drug use

52
Q

What are the characteristics of acute infective endocarditis?

A

Abrupt onset of shaking chills, high spiking fevers, and rapid valve destruction

53
Q

What is the difference in heart valve destruction between vidians group streptococci and staphylococcus aureus?

A

Vidians group streptococci are eating the valve slowly which staphylococcus aureus eats the valve quickly

54
Q

What 2 streptococci groups are associated with subacute bacterial endocarditis?

A

Viridans group streptococci and group D streptococci

55
Q

What subgroup of vidians group streptococci are often found in abscesses?

A

Streptococci intermedius group

*IMmediately USses (asses) for ABSCESS

56
Q

What streptococci are in the streptococci intermedius group?

A

S. Intermedius, S. Constellatus, and S. Angiosus

57
Q

What are the group D streptococci?

A

Enterococci and non-enterococci

58
Q

What bacteria are in the enterococci group of group D streptococci?

A

Enterococcus faecalis and Enterococccus faecium

59
Q

What bacteria are in the non-enterococci subgroup of group D streptococci?

A

Streptococcus bovis and streptococcus equinus

60
Q

What is the hemolytic patten for group D streptococci?

A

Alpha-hemolytic

61
Q

Where do the enterococci (faecalis and faecium) take residence?

A

Intestines and are considered normal bowel flora

62
Q

What is the unique characteristic about enterococci?

A

They grow well in bile and NaCl

63
Q

Who is the main target for enterococci?

A

Weak hospitalized patients (nosocomial- hospitally required)

64
Q

What is the unique characteristic of streptococcus bovis?

A

Marketable association between S. Bovis and colon cancer

*BOVIS in the BLOOD: Better Beware, CANCER in the BOWEL

65
Q

What major diseases are associated with Streptococus pneumoniae?

A

Bacterial pneumonia and meningitis in adults
Otitis media in children
*Pneumococcus is to Parents what group B Streptococcus is to Babies

66
Q

What is the shape of pneumococcus?

A

Lancet-shaped gram + cocci arranged in pairs (diplococci)

67
Q

What is the major virulence factor of pneumococcus?

A

Polysaccharide capsule that protects the organism from phagocytosis

68
Q

What are the 2 important lab tests that identify pneumococcus?

A

Quellung reaction and Optochin sensitivity

69
Q

What is the Quellung reaction?

A

When pneumococci are mixed with antiserum and methylene blue, the capsule will appear to swell

70
Q

What is the Optochin sensitivity test?

A

Disc with Optochin is placed in an agar dish- if there is no growth then it is streptococcus pneumoniae but if there is growth present then it is Streptococus Viridans

71
Q

What is the patient manifestation of pneumocoal pneumonia?

A

Sudden occurrence, shaking chills (rigors), high fevers, chest pain with respirations, and shortness of breath

72
Q

What occurs in the lung when exposed with pneumococcal pneumonia?

A

Lung alveoli or lobe fills with white blood cells (pus), bacteria and exudate
*can be detected on X Ray

73
Q

What is the appearance of the patient’s sputum if they have pneumococcal pneumonia?

A

Yellow-green phlegm

74
Q

What is the classic sign of meningitis in adults?

A

Nuchal rigidity (a stiff neck)

75
Q

What drug is Stretococcus pneumoniae now resistant to?

A

Penicillins

COM MOD 2.2 Bacteria 1 (12 decks)

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