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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
Streptococcus has 3 broad virulence factors:
(1) structural compounds, (2) enzymes, (3) toxins
26
Lipoteichoic acid
• Adhesion • Cytotoxic for most host cells
27
Capsule (slime layer)
- 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)
28
M protein
• Adhesion and inhibition of phagocytic ingestion. • Protein M binds the Fc region of IgG & prevents opsonization
29
Protein G
• 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
30
Nuclease (Type A,B, C, & D)
• 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
31
Streptokinases catalyze conversion of _______ to _____, leading to digestion of _____ (lyse ____ ____ to escape and spread from the ____)
plasminogen, plasmin, fibrin, blood clots, clots
32
Hyaluronidase
• Hydrolyzes hyaluronic acid (spreading between cells)
33
C5a peptidases
• Destroy C’ chemotactic signals (C5a); thus blocks chemotaxis or host defense cell recruitment to the infection site
34
Hemolysin (alpha, beta, gamma)
• destroys RBCs, neutro/mac/plat
35
Exotoxins (streptolysin O & S)
1. Hemolytic on blood agar 2. kills many cells including phagocytes 3. Inhibit phagocyte attraction (inhibit chemotaxis)
36
Pyrogenic exotoxins (types A, B, & C)
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
Streptococcus disease pathogenesis: from ? --> ?
throat, eye/ear, skin, & urogentital infections to pneumonia, endocarditis, meningitis, & shock pus = especially in horses vaginitis travels to blood vessels --> heart --> brain
38
Streptococcus spp. advance from four directions (?) to become systemic disease
cutaneous, throat, mammary, & urogenital
39
Streptococcous pyogenis is ?
Flesh eater
40
______ Streptococcus groups based on clinical significance
Four
41
Streptococcus pyogenes-->?
Throat and dermatological infection
42
Streptococcus pneumonaie
The aggressive/virulent that infects upper respiratory tract and systemic infections  causes pneumonia, septicemia & meningitis
43
Streptococcus agalctiae
Reproductive tract of women  causes vaginitis, postpartum endometritis, septicemia pneumonia and neonatal septicemia, meningitis
44
S. suis – from ? S. gallolytics – from ?
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
Streptococcus pyogenes in humans • Infect ____ ____ worldwide each year
700 million
46
Streptococcus pyogenes causes ?
scarlet fever = pharyngitis • “strep throat” infection • painful swallowing • lymph node and tonsil infection • fever
47
Streptococcus pyogenes causes rash -->
a pathognomonic strawberry rash, which resembles sandpaper texture or tongue resembles goose bumps
48
Streptococcus pyogenes also causes cutaneous lesion • necrotizing skin fasciitis, leading to “flesh eating” by its pyrogenic exotoxins
49
Streptococcus pyogenes
50
Streptococcus pyogenes
51
Strawberry/sandpaper texture tongue seen in scarlet fever
52
Describe streptococcus (throat infection) in horses
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
Describe streptococcus (generalized infection and reproductive tract infection form) in horses
2. 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
55
Strept equi -->
Equine strangles
56
A horse with strangles develops...
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
Equine strangles caused by strept equi
58
equine strangles
59
Strept equi
60
Describe throat infection by Streptococcus in pigs
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
Describe general infection by Streptococcus in pigs
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
How does streptococcus suis impact the swine industry?
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
In humans, streptococcal toxic shock syndrome causing
1. purpura hemorrhagica on the leg 2. gangrene extending down to the foot
64
Streptococcal toxic syndrome
65
What are the four forms of streptococcus in pets?
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
What is the most aggressive strain of streptococcus in pets?
The most aggressive (major problem) - by S. canis
67
What is the an emerging strain, that is causing serious problems, of streptococcus in pets?
2. An emerging problem - S. equi subsp. Zooepidemicus
68
Which strain of streptococcus causes occasional problems in pets?
. Occasional problems are by the following: • S. agalactiae, S. pneumoniae, S. suis, S. pyogenes
69
S. canis affects pets by causing
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
S. canis
71
severe acute & diffuse bronchopneumonia Can be by S. canis & S equi subsp. zooepidemicus infection
72
Diseases of Streptococcus in ruminants
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
Of all pathogens causing bovine mastitis, 23-50% are by ________ spp. in the world
Streptococcus
74
Greening (viridians) or alpha-hemolytic Streptococcus group includes?
This group includes: S. miti, S. mutans, S. salivarius, S. sanguis, S. miller group
75
Habitat of greening (viridians) or alpha-hemolytic Streptococcus group
Habitat: normal flora of oral cavity, intestine, urethra
76
Greening (viridians) or alpha-hemolytic Streptococcus group endogenous infection?
Endogenous infection: dental caries, endocarditis, mixed infection within oral cavity (e.g. purulent abscesses)
77
Greening (viridians) or alpha-hemolytic Streptococcus group
78
Isolation and identification methods for diagnosis of Streptococcus
Or protein M based ELISA (serology)
79
Treatment for strept.;
not as resistant as staph.
80
Control and prevention by improving hygiene and wellbeing
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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