W34/Micro Prac Flashcards
Bacteria are cultured from a wound swab. What would make us think it was infection not colonisation?
Presence of polymorphs
Which drug is the useful derivative of methicilin?
Flucoxacilin
sp
To which drug to bugs develop the same resistance mechanism as that to methicillin?
Cefotaxime
Why do we take 3 sets of blood for bacteraemia?
Bacteraemia can be transient (like in the case of shedding from a valve vegetation)
What’s the colony morphology of staph epidermidis on HBA
White growth
What’s the colony morphoology of staph epidermidis on MAC?
Pale pink
What’s the gram morphology of staph epidermidis?
Gram +’ve cocci in clusters
What are some common causes of sub-acute endocarditis?
Viridans streptococci (alpha-greening strep)
Enterococci
Staph epidermidis
Why could staph epidermidis on blood culture be a false positive?
Contamination from skin flora
of the patient or HCW
Viridans strep are normal flora in which body system?
Respiratory
What are the two most common causes of acute endocarditis?
Staph a. Strep pyogenes (GAS)
Which groups of people are susceptible to endocarditis?
Valve disease
Breaches skin barrier - esp indwelling IV catheter
What are the 3 main complications of endocarditis?
Septic emboli (causing ischaemia, or abcess/focal infections)
Valve damage
Type 3 hypersensitivity/immune complex disease
How long is an AB course to treat endocarditis? Why?
Long ~6weeks.
As the endocarditis is a biofilm, which has a slow rate of growth
What infection is staph. epidermidis renowned for?
Infection of prosthetics (valves, pacemakers, joints)
