Strep & Staph Flashcards
Streptococcus is a Gram ___________ cocci
Positive
Streptococcus spp. are usually what type of pathogen?
Facultative anaerobes
Which bacteria forms a ‘twisted chain’?
Streptococcus
Notice how they clump in these long chains.
Which Streptococcus species are non-pyogenic?
Streptococcus suis and Streptococcus pneumoniae (these are the exceptions - the rest are pyogenic)
Which bacteria is an obligate parasite of cow mammary glands?
Streptococcus agalactiae
Which bacteria causes the least severe mastitis and what causes the most severe?
Least severe = Streptococcus agalactiae
Most severe = E. coli
What are the big five pathogens causing disease in vet med?
- Streptococcus
- Staphylococcus
- E. coli
- Salmonella
- Clostridium
How do we grade the quality of milk and rate the level of mastitis?
By counting the number of somatic cells per mL of milk. Normal milk has <200,000 somatic cells/mL but milk from a serious mastitis infection will have >5,000,000
Which four toxins does Streptococcus agalactiae produce?
- Sphingomyelinase (beta toxin)
- Neuraminidase
- Hemolysin
- Lipoteichoic acid
What are five virulence factors held by Streptococcus agalactiae and what do they allow them to do?
- Type 3 capsular polysaccharide (blocks C3 opsonization in complement pathway)
- Pilus (allows bacteria to adhere to cells)
- C/R/X proteins (allows for colonization)
- EspA (blocks phagocytosis)
- CAMP factor (potentiates beta toxin)
True or False: Mastitis caused by Streptococcus agalactiae is not contagious and therefore is not a significant cause of economic loss to dairy farmers
FALSE!!! It is contagious and does cause significant losses
Which bacteria causes environmental mastitis that is not contagious?
Streptococcus uberis
What bacteria causes contagious and environmental mastitis?
Streptococcus dysgalactiae
What does Streptococcus dysgalactiae equisimilis cause in piglets?
- Septicemia
- Arthritis
- Meningitis
- Endocarditis
(SAME)
What does Streptococcus suis cause in pigs?
- Swollen joints
- Meningitis
- Pneumonia
What are two virulence factors held by Streptococcus suis?
- Capsular polysaccharide (blocks opsonization by C3 in complement pathway)
- Suilysin (a cytotoxic exotoxin that creates holes in target cell membranes)
What pathogen causes strangles in horses?
Streptococcus equi equi
Is Streptococcus equi equi zoonotic?
No, but it is very contagious from animal to animal
What are clinical signs of strangles?
- Abscesses form around lymph nodes in the throat which makes it hard to breathe (you need to drain these abscesses)
- Mucopurulent nasal discharge
What are seven virulence factors of Streptococcus equi?
- Hyaluronic acid capsule (prevents phagocytosis)
- Iron acquisition
- Streptolysin S toxin
- Streptokinase
- IgG endopeptidases
- Antiphagocytic M-protein (blocks C3 opsonization)
- Superantigens (stimulates overzealous immune response to draw in neutrophils)
What are four complications of strangles?
- Guttural pouch disease
- Persistent carriers
- Metastatic abscessation (bastard strangles)
- Purpura hemorrhagica
What are three ways you can diagnose strangles?
- Swabs from nasal discharge, nasopharynx, or draining abscess
- Culture
- PCR
What is a common source of spreading strangles?
Shared water troughs (it can live in water for 6 weeks)
Streptococcus equi zooepidemicus is associated with which four diseases in horses?
Shipping fever, endometriosis, infectious abortion, pneumonia
