Streptococcus Flashcards
Streptococcus are Gram (__)
Gram (+)
What are the major characteristics of Streptococci? (5)
- Fastidious bacteria
- hemolysis on blood agar
- facultative anaerobes
- catalase (-)
- susceptible to desiccation
What suppurative conditions (pus) do Streptococcus cause? (5)
- Mastitis
- Metritis
- Polyarthritis
- Meningitis
- Pneumonia
What is the habitat for Streptococcus species?
Usually are commensals - found in the normal flora of the upper respiratory and lower urogenital tract
T/F Most Streptococcal infections are opportunistic
TRUE
What type of Streptococcal specimen are collected?
pus or exudates
T/F Streptococcal specimen require transport medium.
True: highly susceptible to desiccation
How do we culture Streptococci?
Culture on blood agar plates, incubate aerobically at 37°C for 24 to 48 hours
Does Sterptocci grow on MacConkey agar?
no
What media is used for Streptococcus agalactiae and other streptococci associated with mastitis?
Edwards media
Virulence factors of Streptoccus spp. include what five factors?
- Adhesins (lipoteichoic acid) = Protein F
- Anti-phagocytic M protein
- Capsule (antiphagocytic)
- Lytic enzymes (hyaluronidase and proteases)
- Toxins
Pathogensis of Streptococci spp is associated with what type of clinical signs?
pyogenic infections
abscess formation
septicemia
other suppurative conditions
T/F Beta-hemolytic species are generally more pathogenic than those producing alpha-hemolysis
TRUE
Can Streptococcal species survive long outside a host?
NO - they are susceptible to desiccation
Which Streptococcus spp. is non-pyogenic and associated with pigs?
S. suis
Unlike Staphylococcus, Streptococcus is susceptible to what antibiotics?
Usually highly susceptible to penicillin
Streptococcus are naturally resistant to what type of antibiotics?
aminoglycosides
T/F Acquired antimicrobial resistance is not frequent with Streptococcus.
TRUE
Beta-hemolysis produces what type of hemolysis on blood agar?
a complete zone of hemolysis
Alpha-hemolysis produces what type of hemolysis on blood agar?
partial or incomplete hemolysis
Gamma-hemolysis produces what type of hemolysis on blood agar?
no observable hemolysis
S. agalactiae, S. equi, S. zooepidimicus posses what hemolysis classification?
Beta-hemolytic streptococci - complete hemolysis
groups of species of pathogenic streptococci is based on what?
Lancefield grouping
Differentiation of streptococci is done using what molecular tests
Multiplex PCR - pathogens causing bovine mastitis
What are the most important Streptococcal diseases of veterinary importance? (6)
- Bovine mastitis
- Strangles in horses
- Pneumonia
- Septicemia
- Arthritis
- Meningitis
S. suis, S. dysgalactiae, and S. uberis all possess what hemolysis classification?
Alpha-hemolytic streptococci (incomplete - “greenish” discoloration)
What streptococci species cause chronic mastitis of the milk ducts in Cattle, Sheep and Goats?
S. agalactiae
Bovine streptococcal mastitis is caused by what three Streptococci spp?
Streptococcus agalactiae
Streptococcus dysgalactiae
Streptococcus uberis