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Bacteriology/Mycology > Week 2 - Streptococcus > Flashcards

Week 2 - Streptococcus Flashcards

1
Q

Streptococcus is a Gram _____ cocci arranged in _____

A

positive, chains

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2
Q

Streptococcus is a Facultative anaerobe, meaning ?

A

O2 availability is not critical for survival

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3
Q

Streptococcus is ________ and ______ forming (like Staphylococcus)

A

non-motile, non-spore

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4
Q

Streptococcus are fastidious in their growth requirement (unlike Staphylococcus). Meaning?

A

i.e. requires a nutritionally rich media for growth
• Thus, they cannot survive for long away from the animal host

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5
Q

Streptococcus cannot grow in media containing ___ _____?

A

high salt, (> 6.5%) (unlike the salt
resistant Staphylococcus)

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6
Q

Streptococcus is Catalase ______

A

negative (unlike Staphylococcus that is catalase + and
arranged in grape-like appearance)

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7
Q

What culture media are used for Streptococcus?

A

Blood agar (for every bacteria - universal, enriching media)
-Allows determination of the type of hemolysin toxin
produced by the isolates (beta, alpha, gamma)
Edward media
- Edward media for selective isolation and identification of
Streptococci

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8
Q

Beta-hemolytic group is the ______ _____ streptococci

A

most pathogenic

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9
Q

Alpha-hemolysis group results in ______ and _______ _______ with _____ color (viridiant). Most commensal streptococci of ______ _____ fall under this classification e.g. ?

A

partial, incomplete, hemolysis, green, upper respiratory, S. pneumoniae

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10
Q

Gamma-hemolytic group: most ____ Streptococci fall under this classification ?

A

fecal, e.g. S.
gallolyticus, S. faecalis (now named Enterococcus faecalis)

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11
Q

The Streptococcus cell surface is decorated with many proteins & carbohydrate polymers including

A

Capsule = mucoid; Useful for serotypying strains within a species
Protein F = atachment
Pili = conjugation
Protein M = attachment and serotyping
- Useful for serotyping within a species by ELISA as well as for vaccine production.
Carbohydrates = named Lancefield (LF) (microbiologist that used carbohydrates to differentiate different species of streptococcus by producing antibodies against
- Useful for Lancefield (LF) serogrouping multiple species into a cluster/set
Protein G

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12
Q

Streptococcus spp. serogrouping using common ____ ____ carbohydrate (Lancefied serogrouping method)

A

cell wall

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13
Q

Describe the Lancefled serogrouping method

A

Extracted carbohydrate, produced different antibodies (A-D). Each letter represents a different species. Mixed carb with antibody. If agglutinates = match

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14
Q

Sero-grouping using antibody by ________ of _____ antigens on bacterial cell wall.
- This sero-grouping method was developed by _______ _____ in 1933

A

agglutination, carbohydrate, Rebecca Lancefield

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15
Q

Accordingly, the 50 Streptococcus species are grouped into:
- 19 serogroups (A-U, without I & J) are known
based on their unique carbohydrate antigen on the cell wall
- Of the 19, sero-groups A, B, C, D, E, and G are clinically
important in human and veterinary medicine

A
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16
Q

Methods for diagnosis of Streptococcus isolates from suspected cases

A

Gram stain = microscope –> see chain of rods, cocci
Catalase test = do you see bubble –> no because catalase negative
Blood agar hemolysis = tells you pathogenicity
Serology = agglutination

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17
Q

Classification of Streptococcus species by two
tests:

A

hemolysis and antibody agglutination

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18
Q

Beta = group a, b, c, e, g (more dangerous)
- s. pyrogenes = tonsilitis in humans
- s. aga = B
-
Gamma = enteroccoccus and strep. They are group D antibodies

A
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19
Q

Each serotype needs their own _____.

A

vaccine

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20
Q

S. pneumoniae causes

A

Meningitis

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21
Q

Habitat of Strept. Commensals of humans, animals, fish, and insects on/in:

A

 skin
 upper respiratory
 tonsil
 digestive tract
 lower urogenital tract (vagina)
 udder/teat duct….in milk & dairy products

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22
Q

Strep are also found in

A

 food and plant material
 soil
 fecal contaminated water

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23
Q

Commensal of the normal flora ………………….(Opportunistic organism)
 Streptococcal disease occurs when the bacteria enter
 cuts
 abrasions
 other wounds or
 when the immune system becomes weakened
 primary diseases such as viruses, mycoplasmosis, etc.

A
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24
Q

The bacteria can be spread between animals by

A

• direct contact
• aerosol
• fomites
• sometimes ingestion (oral)

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25
Q

Streptococcus has 3 broad virulence factors:

A

(1) structural compounds, (2) enzymes, (3) toxins

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26
Q

Lipoteichoic acid

A

• Adhesion
• Cytotoxic for most host cells

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27
Q

Capsule (slime layer)

A
  • prevents phagocytosis
  • prevents chemotaxis
    • Adhesion
    • Hide/cover the surface of the bacterial cell by depositing host sialic
    acid residues on their surfaces
    • Thus, capsule prevents bacterial recognition by phagocytes, prevents
    complement assisted opsonization (inhibit phagocytic killing)
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28
Q

M protein

A

• Adhesion and inhibition of phagocytic ingestion.
• Protein M binds the Fc region of IgG & prevents opsonization

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29
Q

Protein G

A

• Compete with complement to bind with the constant Fc region of IgG of diverse animal species.
• It binds and accumulates IgG on the bacterial surface through nonimmune binding, leading to prevention for opsonization

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30
Q

Nuclease (Type A,B, C, & D)

A

• Facilitate liquefaction of pus (converts pus to resources/substrates
to utilize it and grow)
• Have DNase activity (A & C) and RNase activity (B&D) to destroy
host cells and host defense

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31
Q

Streptokinases catalyze conversion of _______ to _____, leading to digestion
of _____ (lyse ____ ____ to escape and spread from the ____)

A

plasminogen, plasmin, fibrin, blood clots, clots

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32
Q

Hyaluronidase

A

• Hydrolyzes hyaluronic acid (spreading between cells)

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33
Q

C5a peptidases

A

• Destroy C’ chemotactic signals (C5a); thus blocks chemotaxis or
host defense cell recruitment to the infection site

34
Q

Hemolysin (alpha, beta, gamma)

A

• destroys RBCs, neutro/mac/plat

35
Q

Exotoxins
(streptolysin
O & S)

A
  1. Hemolytic on blood agar
  2. kills many cells including phagocytes
  3. Inhibit phagocyte attraction (inhibit chemotaxis)
36
Q

Pyrogenic exotoxins (types A, B, & C)

A

Cause
1. fever
2. rash that resembles strawberry e.g. on tongue
3. cardiac and liver necrosis
4. T cell division (mitogenic).
5. release floods of cytokines i.e. Superantigen
 Normally antigens activate only 0.0001-0001% of the body’s T
cells,
 but superantigens activate too many T cells to produce
cytokines storm, leading to shock & multiple organ failure
6. Increase permeability of endothelium (shock) & bloodbrain barrie

37
Q

Streptococcus disease pathogenesis: from ? –> ?

A

throat, eye/ear, skin, & urogentital infections to pneumonia, endocarditis, meningitis, & shock

pus = especially in horses
vaginitis
travels to blood vessels –> heart –> brain

38
Q

Streptococcus spp. advance from four directions (?) to become systemic disease

A

cutaneous,
throat, mammary, & urogenital

39
Q

Streptococcous pyogenis is ?

A

Flesh eater

40
Q

______ Streptococcus groups based on clinical significance

A

Four

41
Q

Streptococcus pyogenes–>?

A

Throat and dermatological infection

42
Q

Streptococcus pneumonaie

A

The aggressive/virulent that infects upper
respiratory tract and systemic infections
 causes pneumonia, septicemia & meningitis

43
Q

Streptococcus agalctiae

A

Reproductive tract of women
 causes vaginitis, postpartum endometritis, septicemia
pneumonia and neonatal septicemia, meningitis

44
Q

S. suis – from ?

S. gallolytics – from ?

A
  1. pig …cause in humans meningitis, septic,
    arthritis, subcutaneous hemorrhage, shock, pneumonia,
    permanent hearing loss & death
  2. chicken ….cause in humans colorectal
    cancer and osteomyelitis
    Emerging zoonotic Streptococcus of humans that
    migrate from animals to humans
45
Q

Streptococcus pyogenes in humans
• Infect ____ ____ worldwide each year

A

700 million

46
Q

Streptococcus pyogenes causes ?

A

scarlet fever = pharyngitis
• “strep throat” infection
• painful swallowing
• lymph node and tonsil infection
• fever

47
Q

Streptococcus pyogenes causes rash –>

A

a pathognomonic strawberry rash,
which resembles sandpaper texture or
tongue resembles goose bumps

48
Q

Streptococcus pyogenes also causes cutaneous lesion
• necrotizing skin fasciitis, leading to
“flesh eating” by its pyrogenic exotoxins

A
49
Q
A

Streptococcus pyogenes

50
Q
A

Streptococcus pyogenes

51
Q

Strawberry/sandpaper texture tongue seen in scarlet fever

A
52
Q

Describe streptococcus (throat infection) in horses

A
  1. Throat infection (also called strangles in equine which equivalent of scarlet
    fever in humans) = pharyngitis
     Causes pus accumulation in throat regions, genital & suppurative conditions, mastitis & purpura
    haemorrhagica due to vascular damage
     Streptococcus equi subsp. Equi
53
Q

Describe streptococcus (generalized infection and reproductive tract infection form) in horses

A
  1. Generalized infection & reproductive tract infection form:
     causes vaginitis, abortion, postpartum endometritis,
     septicemia, pneumonia and neonatal (navel ill, septicemia, meningitis)
     S. dysgalatiae subsp. Equisimilis
     S equi subsp. Zooepidemicus

Affects diverse host ranges: pets, poultry, ruminants, pigs

54
Q
A
55
Q

Strept equi –>

A

Equine strangles

56
Q

A horse with strangles develops…

A

A horse with strangles develops:
 abscesses in the lymph nodes of the head & neck,
 causing coughing
 difficulty swallowing
 fever up to 106°F
 yellow-colored nasal discharge from both the nose and eyes
 Thick pus filled guttural poach

57
Q
A

Equine strangles caused by strept equi

58
Q
A

equine strangles

59
Q
A

Strept equi

60
Q

Describe throat infection by Streptococcus in pigs

A

Throat infection (also called “porcine strangles” = pharyngitis
 Similar to equine strangles or scarlet fever in humans
 pus accumulation in throat regions (jowl abscess = feeder
boils),
 contagious cervical lymphadenitis diseases in pigs &
 purpura haemorrhagica due to vascular damage
 Streptococcus porcinus – it is rare now

61
Q

Describe general infection by Streptococcus in pigs

A

Generalized infection: The aggressive form affecting ear,
eyes, lung, brain, joints/bones
 causing deaf, blindness, septicemia, pneumonia, meningitis,
polyarthritis
 S. suis – the most common problem in pig industry
 S equi subsp. Zooepidemicus (occasionally)

62
Q

How does streptococcus suis impact the swine industry?

A

Affects the swine industry by causing
1. Pneumonia
2. Septicemia,
3. meningitis/ataxia/loss of balance/shaking,
4. polyarthritis/lameness
5. Abortion
6. metritis
7. blindness
8. deaf

63
Q

In humans, streptococcal toxic shock syndrome causing

A
  1. purpura hemorrhagica on the leg
  2. gangrene extending down to the foot
64
Q
A

Streptococcal toxic syndrome

65
Q

What are the four forms of streptococcus in pets?

A

Four forms like humans and equines
1. Throat infection form (“pet strangles”) -
S. canis
2. Generalized infection: The aggressive
systemic form (septicemia, pneumonia,
meningitis) - S. canis
3. Eye/ear form - S. canis
4. Reproduction form (vaginitis, abortion,
endometritis, mastitis, prostitis) - S.
agalactiae (but also S. canis)

66
Q

What is the most aggressive strain of streptococcus in pets?

A

The most aggressive (major problem) - by S. canis

67
Q

What is the an emerging strain, that is causing serious problems, of streptococcus in pets?

A
  1. An emerging problem - S. equi subsp. Zooepidemicus
68
Q

Which strain of streptococcus causes occasional problems in pets?

A

. Occasional problems are by the following:
• S. agalactiae, S. pneumoniae, S. suis, S. pyogenes

69
Q

S. canis affects pets by causing

A
  1. Blindness (conjunctivitis)
  2. Otitis (deaf)
  3. Septicemia,
  4. contagious lymphadenitis (mimic human scarlet fever)
  5. pneumonia and fibrinous pleurisy
  6. Vaginitis, abortion, metritis by S. canis & S. agalactiae
  7. Urinary tract infection (cystitis) - S. agalactiae
70
Q
A

S. canis

71
Q
A

severe acute & diffuse bronchopneumonia
Can be by S. canis & S equi
subsp. zooepidemicus infection

72
Q

Diseases of Streptococcus in ruminants

A
  1. S. uberis: Mastitis
  2. S. dysgalatiae: Acute contagious/environmental
    mastitis, Polyarthritis
  3. S. agalatiae: Chronic contagious mastitis
  4. Occasionally: S. equi subsp. Zooepidemicus -
    Metritis (abortion) & mastitis
73
Q

Of all pathogens causing bovine mastitis, 23-50% are by ________ spp. in the world

A

Streptococcus

74
Q

Greening (viridians) or alpha-hemolytic
Streptococcus group includes?

A

This group includes: S. miti, S. mutans,
S. salivarius, S. sanguis, S. miller group

75
Q

Habitat of greening (viridians) or alpha-hemolytic
Streptococcus group

A

Habitat: normal flora of oral cavity,
intestine, urethra

76
Q

Greening (viridians) or alpha-hemolytic
Streptococcus group endogenous infection?

A

Endogenous infection: dental caries,
endocarditis, mixed infection within oral
cavity (e.g. purulent abscesses)

77
Q
A

Greening (viridians) or alpha-hemolytic
Streptococcus group

78
Q

Isolation and identification methods for
diagnosis of Streptococcus

A

Or protein M based ELISA (serology)

79
Q

Treatment for strept.;

A

not as resistant as staph.

80
Q

Control and prevention by improving hygiene and wellbeing

A

Control strategies are as similar as in Staphylococcus —hygiene and wellbeing
• Since Streptococcus organisms are normally found on animals, it is difficult to
prevent infections.
 Reducing stress (overcrowding, poor ventilation, high humidity)
 Practicing good hygiene, strict sanitation of facilities and instruments
 Cleaning wounds
 Segregation of infected animals and treat them early
 Control of primary diseases such as viruses, mycoplasmosis, etc. that interact with Streptococcus
is important.
• Vaccine is available for S. pneumoniae in humans

Bacteriology/Mycology (40 decks)

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