Streptococcus and Enterococcus Flashcards
What does Streptococcus and Enterococcus look like on gram stain?
gram positive, chaining cocci - can be square or lemon-shaped
Where do Streptococcus and Enterococcus tend to live?
they are widely distributed in nature - skin and mucous membranes
Typically when can hemolysis be seen in Streptococcus and Enterococcus species?
18-24 hours
What are the growth requirements for Streptococci?
some require serum or blood for growth, 35-37 C, faculative anaerobes, decreaased O2 and increased CO2 helps on primary isolation
What are the growth requirements for Enterococcus?
less fastidious than Streptococcus, resistant to esculin, tolerate higher temperatures, and highly resistant to antimicrobials
How do Streptococci respond to catalase tests?
they are catalase negative
What is a useful test in determining what type of streptococcus species is present?
carbohydrate fermentation tests
What do Streptococci colonies look like?
they are smaller than staphylococcal colonies and are usually clear
What type of hemolysis can Streptococci species have?
alpha, beta, or no hemolysis
What type of hemolysis is shown here?
beta
What types of antigens are associated with Streptococci?
group-specific antigens and type-specific antigens
How are the cell wall carbohydrates in streptococci grouped?
into Lancefield groups (A, B, C, etc.)
How is the Lancefield test carried out?
boiling an unknown streptococcus or treating it with acid to destroy the protein antigens
What Lancefield group are capsules important in?
Group A streps
What toxins are associated with Streptococci?
streptolysin-O, streptolysin-S, streptokinase, streptodornase, and hyaluronidase
What type of toxin is streptolysin-O?
it is cholesterol-binding
When are streptolysin-O best seen?
under anaerobic growth conditions
What does streptolysin-O do?
attacks leukocytes, platelets, RBC’s,and fibroblasts
Describe streptolysin-S?
less toxic, non-antigenic, and stable to oxygen
What does streptokinase do?
lyse fibrin
What does streptodornase do?
liquefaction of pus
What lancefield group is streptodornase associated with?
A
What does hyaluronidase do?
break down hyaluronic acid in tissues
What group of strep is Streptococcus pyogenes?
Group A - it is the only species in this group
What species does Streptococcus pyogenes typically infect?
humans
What diseases are associated with Streptococcus pyogenes?
strep throat, scarlet fever, sinusitis, valvular endocarditis, rheumatic fever, glomerulonephritis, and erysipelas in humans
What habitat does Streptococcus pyogeneslive in?
pharyngeal and tonsillar areas
What type of proteins (antigens) are present in Streptococcus pyogenes?
M-proteins, T-proteins, M-associated protein, erythrogenic toxins
Where are M proteins for group A streps located?
on the fibrillar surface to help adhere bacteria together
What is the function of M proteins?
they interfere with the deposition of C3b on the surface of the organism - antiphagocytic
What are M-associated proteins in group A streps associated with?
myocardial tissue
What are erythrogenic toxins responsible for?
the rash in scarlet fever
Where are erythrogenic toxins located?
on bacteriophages
What are group A streps susceptible to?
penicillin-class antimicrobials
What hemolytic pattern in group A streps is associated with not developing resistance?
beta
What group of strep is Streptococcus equi subsp. equi?
Lancefields group C
Streptococcus equi subsp. equi is more fastidius thatn subsp ___________.
zooepidemicus
What do the colonies of Streptococcus equi subsp. equi look like?
mucoid due to presence of a heavy capsule
What species is Streptococcus equi supsp. equi the obligate parasite of?
equidae
How is Streptococcus equisubsp. equi transmitted?
droplet, contact, and fomites
How can Streptococcus equi subs. equi gain entry into their host?
via the nasal mucosa or tonisl and travel to the draining lymph nodes
Why is immunization easier for Streptococcus equi?
because there is essentially only one dominant M-protein
What does Streptococcus equi cytotoxin do?
damages phagocytes and aids intracellular survival
What disease is commonly associated with Streptococcus equi subsp. equi?
strangles
What age of horse does strangles usally effect?
horses under 2 years of age
What symptoms are associated with strangles?
large, painfull abscesses, high fever, and respiratory signs
Why are abscesses so dangerous in horses that have strangles?
because they can interfere with respiration or impinge on nerves and can open internally
What is purpura hemorrhagica?
a delayed immune reaction - horses have high serum IgA
What happens in blood vessel walls in purpura hemorrhagica?
IgA-M protein complexes form and are deposited on blood vessel walls
What symptoms are associated with purpura hemorrhagica?
vasculitis and necrosis of blood vessel walls, fever, edema, and hemorrhages
Aside from purpura hemorrhagica and strangles what other infections are associated with Streptococcus equi?
reproductive tract infections
When is immunity to Streptococcus equi good?
following infection and recovery
How do you immunize against Streptococcus equi?
bacterins, M-protein, and modified live vaccines
What is the treatment for Streptococcus equi in horses?
lance abscesses and penicillin
What are all beta-hemolytic streptococci susceptible to?
penicillin
What group of strep is Streptococcus equi subsp. zooepidemicus?
group C
What hemolytic pattern does Streptococcus equi subsp. Zooepidemicus have?
beta
What happens to Streptococcus equi subsp. Zooepidemicus with age?
they collapse and dry
What is the natural habitat of Streptococcus equi subsp. zooepidemicus?
skin, mucous membranes and tonsils
What diseases are found in horses that are associated with Streptococcus equi subsp. zooepidemicus?
wound infections, secondary invader in respiratory infections, omphalophlebitis, bactermia, polyarthritis, and reproductive tract infections in mares
What disease is found in camelids, alpacas, and llamas that is associated with Streptococcus equi subsp. zooepidemicus?
polyserositis; known as alpaca fever in alpacas
What disease is in dogs is associated with Streptococcus equi subsp. zooepidemicus?
hemorrhagic pneumonia - pyrexia, dyspnea, and hemorrhagic nasal discharge
Are there any vaccines for Streptococcus equi subsp. zooepidemicus?
nope
What group of strep is Streptococcus dysgalactia subsp. equisimilis?
groups c, g, and l
What hemolytic pattern does Streptococcus dysgalactia subsp. equisimilis exhibit?
beta
What in humans is Streptococcus dysgalactia subsp. Equisimilis associated with?
pharyngitis and other infections
What in sows, dogs, and occasionally other animals is Streptococcus dysgalactia associated with?
metritis and cervicitis
What species does Streptococcus dysgalactia cause septicemia and joint infections in?
pigs
Streptococcus dysgalactia is the most common beta-hemolytic strep in what host?
neonatal piglets
What can Streptococcus dysgalactia cause in horses although not common?
strangles
Are there any vaccines for Streptococcus dysgalactia subsp. Equisimilis?
nope
What group of strep is Streptococcus canis?
mostly group G
What type of hemolysis does Streptococcus canis have?
beta
What disease can Streptococcus canis cause in dogs and cats?
tonsillitis, metritis, wound infections, septicemia, and umbilical infections
What can Streptococcus canis cause in humans?
wound infections
What can Streptococcus canis cause in dairy cattle?
mastitis
What strep group is Streptococcus porcinus in?
formally E, now P, U, and V
What main disease process does Streptococcus porcinuscause?
jowl abscesses in swine
What used to be used to treat jowl abscesses in swine?
tetracycline
What infections does Streptococcus porcinus cause in humans?
genitourinary infections
What strep group is Streptococcus suis in?
group D
What hemolytic pattern does Streptococcus suis exhibit?
alpha
What capsular type is the most common in disease for Streptococcus suis?
type 2
How is Streptococcus suis identified best?
carbohydrate fermenration and capsular typing
What virulence factors are associated with Streptococcus suis?
muramidase-released protein, extracellular protein factor, and Suilysin: cholesterol-binding toxin
What does Streptococcus suis causein pigs?
septicemia - meningitis, arthritis, and respiratory infections
When is Streptococcus suis transmitted?
at birth
Does immunization of sows against Streptococcus suis provide protection?
very marginal protection
What does Streptococcus suis cause in humans?
septicemia with meningitis, arthritis, pneumonia, and endocarditis
How does Streptococcus suis infect humans?
it enters through cuts, abrasions, conjunctiva, etc.
What happened in china due to Streptococcus suis?
toxic shock syndrome
What are known as the mastitis streptococci?
S. agalactiae, S. dysgalactia, S. uberis, and entercocci
What type of hemolysis does S. agalactiae exhibit?
narrow-zone beta hemolysis
Is S. agalactiae CAMP positive or negative?
positive
How does S. agalactiae spread?
via milking equipment
What is the pathogenesis of S. agalactiae?
it is acute localized mastitis initially and then becomes chronic and the mammary gland loses much of its functional tissue
How do you control S. agalactiae?
Culture every quarter, treat only the infected cows, re-culture and re-treat, re-culture and cull the non-responders
Is there immunization for S. agalactiae?
nope
What does S. agalactiae cause in fish?
skin lesions
In humans what strep group is S. agalactiae?
B
What does S. agalactiae cause in humans?
middle ear infections, meningitis, and septicemia in infants and prenant women
What strep group is S. dysgalactiae subsp. Dysgalactiae?
C
What hemolytic pattern does S. dysgalactiae subsp. dysgalactiae exhibit?
alpha
Where does S. dysgalactiae subsp. dysgalactiae typically live?
on the skin and in the oral cavity
What does S. dysgalactiae subsp. Dysgalactiae produce?
M-like prortein, an Fc-receptor protein, and a fibronectin receptor
What strep group does S. uberis belong to?
none
What hemolytic pattern does S. uberis exhibit?
no hemolysis but a slight greening of the agar
Where does S. uberis typically live?
GI tract in cattle, skin, and in bedding
What specific cows does S. uberis cause mastitis in?
loose-housed dairy cattle
What hemolytic pattern does Enterococci exhibit?
alpha hemolysis
Where is enterococci common?
in intestinal tract and ‘other sites’
What commonly does enterococci cause?
valvular endocarditis, mastitis, and dental plaque
What does S. pneumoniae cause in humans?
respiratory tract infections (diplococcal pneumonia)
What is capsular type III of S. pneumoniae the cause of and in what species?
respiratory disease in horses
