Week 2 - Streptococcus Flashcards
Streptococcus is a Gram _____ cocci arranged in _____
positive, chains
Streptococcus is a Facultative anaerobe, meaning ?
O2 availability is not critical for survival
Streptococcus is ________ and ______ forming (like Staphylococcus)
non-motile, non-spore
Streptococcus are fastidious in their growth requirement (unlike Staphylococcus). Meaning?
i.e. requires a nutritionally rich media for growth
• Thus, they cannot survive for long away from the animal host
Streptococcus cannot grow in media containing ___ _____?
high salt, (> 6.5%) (unlike the salt
resistant Staphylococcus)
Streptococcus is Catalase ______
negative (unlike Staphylococcus that is catalase + and
arranged in grape-like appearance)
What culture media are used for Streptococcus?
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
Beta-hemolytic group is the ______ _____ streptococci
most pathogenic
Alpha-hemolysis group results in ______ and _______ _______ with _____ color (viridiant). Most commensal streptococci of ______ _____ fall under this classification e.g. ?
partial, incomplete, hemolysis, green, upper respiratory, S. pneumoniae
Gamma-hemolytic group: most ____ Streptococci fall under this classification ?
fecal, e.g. S.
gallolyticus, S. faecalis (now named Enterococcus faecalis)
The Streptococcus cell surface is decorated with many proteins & carbohydrate polymers including
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
Streptococcus spp. serogrouping using common ____ ____ carbohydrate (Lancefied serogrouping method)
cell wall
Describe the Lancefled serogrouping method
Extracted carbohydrate, produced different antibodies (A-D). Each letter represents a different species. Mixed carb with antibody. If agglutinates = match
Sero-grouping using antibody by ________ of _____ antigens on bacterial cell wall.
- This sero-grouping method was developed by _______ _____ in 1933
agglutination, carbohydrate, Rebecca Lancefield
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
Methods for diagnosis of Streptococcus isolates from suspected cases
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
Classification of Streptococcus species by two
tests:
hemolysis and antibody agglutination
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
Each serotype needs their own _____.
vaccine
S. pneumoniae causes
Meningitis
Habitat of Strept. Commensals of humans, animals, fish, and insects on/in:
skin
upper respiratory
tonsil
digestive tract
lower urogenital tract (vagina)
udder/teat duct….in milk & dairy products
Strep are also found in
food and plant material
soil
fecal contaminated water
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.
The bacteria can be spread between animals by
• direct contact
• aerosol
• fomites
• sometimes ingestion (oral)
Streptococcus has 3 broad virulence factors:
(1) structural compounds, (2) enzymes, (3) toxins
Lipoteichoic acid
• Adhesion
• Cytotoxic for most host cells
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)
M protein
• Adhesion and inhibition of phagocytic ingestion.
• Protein M binds the Fc region of IgG & prevents opsonization
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
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
Streptokinases catalyze conversion of _______ to _____, leading to digestion
of _____ (lyse ____ ____ to escape and spread from the ____)
plasminogen, plasmin, fibrin, blood clots, clots
Hyaluronidase
• Hydrolyzes hyaluronic acid (spreading between cells)
C5a peptidases
• Destroy C’ chemotactic signals (C5a); thus blocks chemotaxis or
host defense cell recruitment to the infection site
Hemolysin (alpha, beta, gamma)
• destroys RBCs, neutro/mac/plat
Exotoxins
(streptolysin
O & S)
- Hemolytic on blood agar
- kills many cells including phagocytes
- Inhibit phagocyte attraction (inhibit chemotaxis)
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
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
Streptococcus spp. advance from four directions (?) to become systemic disease
cutaneous,
throat, mammary, & urogenital
Streptococcous pyogenis is ?
Flesh eater
______ Streptococcus groups based on clinical significance
Four
Streptococcus pyogenes–>?
Throat and dermatological infection
Streptococcus pneumonaie
The aggressive/virulent that infects upper
respiratory tract and systemic infections
causes pneumonia, septicemia & meningitis
Streptococcus agalctiae
Reproductive tract of women
causes vaginitis, postpartum endometritis, septicemia
pneumonia and neonatal septicemia, meningitis
S. suis – from ?
S. gallolytics – from ?
- pig …cause in humans meningitis, septic,
arthritis, subcutaneous hemorrhage, shock, pneumonia,
permanent hearing loss & death - chicken ….cause in humans colorectal
cancer and osteomyelitis
Emerging zoonotic Streptococcus of humans that
migrate from animals to humans
Streptococcus pyogenes in humans
• Infect ____ ____ worldwide each year
700 million
Streptococcus pyogenes causes ?
scarlet fever = pharyngitis
• “strep throat” infection
• painful swallowing
• lymph node and tonsil infection
• fever
Streptococcus pyogenes causes rash –>
a pathognomonic strawberry rash,
which resembles sandpaper texture or
tongue resembles goose bumps
Streptococcus pyogenes also causes cutaneous lesion
• necrotizing skin fasciitis, leading to
“flesh eating” by its pyrogenic exotoxins
Streptococcus pyogenes
Streptococcus pyogenes
Strawberry/sandpaper texture tongue seen in scarlet fever
Describe streptococcus (throat infection) in horses
- 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
Describe streptococcus (generalized infection and reproductive tract infection form) in horses
- 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
Strept equi –>
Equine strangles
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
Equine strangles caused by strept equi
equine strangles
Strept equi
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
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)
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
In humans, streptococcal toxic shock syndrome causing
- purpura hemorrhagica on the leg
- gangrene extending down to the foot
Streptococcal toxic syndrome
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)
What is the most aggressive strain of streptococcus in pets?
The most aggressive (major problem) - by S. canis
What is the an emerging strain, that is causing serious problems, of streptococcus in pets?
- An emerging problem - S. equi subsp. Zooepidemicus
Which strain of streptococcus causes occasional problems in pets?
. Occasional problems are by the following:
• S. agalactiae, S. pneumoniae, S. suis, S. pyogenes
S. canis affects pets by causing
- Blindness (conjunctivitis)
- Otitis (deaf)
- Septicemia,
- contagious lymphadenitis (mimic human scarlet fever)
- pneumonia and fibrinous pleurisy
- Vaginitis, abortion, metritis by S. canis & S. agalactiae
- Urinary tract infection (cystitis) - S. agalactiae
S. canis
severe acute & diffuse bronchopneumonia
Can be by S. canis & S equi
subsp. zooepidemicus infection
Diseases of Streptococcus in ruminants
- S. uberis: Mastitis
- S. dysgalatiae: Acute contagious/environmental
mastitis, Polyarthritis - S. agalatiae: Chronic contagious mastitis
- Occasionally: S. equi subsp. Zooepidemicus -
Metritis (abortion) & mastitis
Of all pathogens causing bovine mastitis, 23-50% are by ________ spp. in the world
Streptococcus
Greening (viridians) or alpha-hemolytic
Streptococcus group includes?
This group includes: S. miti, S. mutans,
S. salivarius, S. sanguis, S. miller group
Habitat of greening (viridians) or alpha-hemolytic
Streptococcus group
Habitat: normal flora of oral cavity,
intestine, urethra
Greening (viridians) or alpha-hemolytic
Streptococcus group endogenous infection?
Endogenous infection: dental caries,
endocarditis, mixed infection within oral
cavity (e.g. purulent abscesses)
Greening (viridians) or alpha-hemolytic
Streptococcus group
Isolation and identification methods for
diagnosis of Streptococcus
Or protein M based ELISA (serology)
Treatment for strept.;
not as resistant as staph.
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
