Streptococci Flashcards
Describe the appearance of streptococci on a microscopic slide
Gram positive - purple
Lancet shaped
How is streptococcus pyogenes spread?
Skin to skin contact
Via the respiratory tract
What does streptococcus pyogenes cause?
Acute pharyngitis
Acute rheumatic fever
Puerperal sepsis
Necrotising fasciitis
What are the virulence factors for streptococcus pyogenes?
Produces pyrogenic exotoxins - causes scarlet fever rash and toxic shock
Produces streptolysin - causes cell lysis and release of lysosomal enzymes
Produces C5a peptidase - inactivates complement protein response
How is streptococcus pyogenes infections treated?
Penicillin
What are the virulence factors for streptococcus pneumoniae?
Bacterial Capsule - makes it difficult to phagocytose
Produces cytolytic toxins - damages cell membranes
How does streptococcus pneumonia cause infection?
Droplet infection from a carrier
Carrier becomes immunodepressed, malnourished/alcoholic
How is streptococcus pneumoniae treated?
Penicillin
What are the potential consequences of a viridans streptococcus infection?
In oral cavity - Dental cavities
In heart valves - Endocarditis
How is viridans streptococcus treated?
Penicillin
