Flashcards in Microbiology Deck (50)
The ability of an organism to cause disease within a host
Name 5 virulence factors
What are adhesins?
Bacterial cell surface components that help the organism stick/adhere to host tissue
What are invasins?
Enable organisms to invade host tissue
What are impedins?
Help the organism avoid the defence/immune response in host tissue
What are aggressins?
Cause direct damage to host tissue + immune cells, affecting the host's ability to cope with disease in the future
What are modulins?
Cause indirect damage to the host by turning the immune system in on itself (host's immune system causes damage to host tissue)
The nasal strain of Staph. aureus can protect the mucosa. True/False?
Staph. epidermidis can occupy up to 100% of our skin. True/False?
Where is the most common entry of Staph. aureus into the body?
Name the 3 particularly important virulence factors of Staph. aureus disease
Fibrinogen-binding protein (adhesin)
Leukocidin (kills leukocytes)
Every strain of Staph. aureus carries every virulence factor. True/False?
Which 2 severe skin diseases is leukocidin associated with?
Leukocidin is more virulent in hospital-acquired MRSA than community-acquired. True/False?
Give an example of a superantigen released by MRSA
TSST-1 (toxic shock)
How exactly do superantigens avoid specific T-cell activation?
Bind to MHC II complex on the outside, i.e. not the conventional binding groove
Name 3 skin infections caused by Strep. pyogenes
How does the Lancefield system classify different subtypes of Step. pyogenes?
(M1 and M3 are predominant; M3 and M18 cause severe, invasive disease)
Which 2 virulence factors are particularly important as adhesins for Strep. pyogenes disease?
Hyaluronic acid (sticky capsule)
CD44 +ve keratinocytes
The bigger the capsule, the less virulent an organism is. True/False?
Where does impetigo usually affect?
Where in the body is Strep. pyogenes normally found?
Which strain of Staph aureus commonly produces abscesses and boils, usually affecting numerous family members at once?
PVL (panton valentine leukocidin)
Which group of Strep causes throat and severe skin infections?
Which bacteria cause impetigo?
Group A Strep
Which bacteria tends to cause nectrotising fasciitis?
Group A Strep (pyogenes)
What is the treatment of choice for Staph aureus?
What is the treatment of choice for Strep pyogenes?
What is necrotising fasciitis?
Bacterial infection spreading under the skin into fascia