Cardiovascular infections

Question 1

List three factors which contribute to keeping blood free of microorganisms?

Answer 1

• Mobility of blood stream
• Phagocytes, Aby, complement
• Phagocytic cells in liver and spleen

Question 2

Which genera/organisms are normally considered to be skin contaminants if isolated from blood culture?.

Answer 2

• Strep. epidermidis
• Bacillus except bacillus anthracis (ovrt pathogen)
• Diptheroids (micellaneous GNB)
• Propionibacterium sp.

Question 3

What is the difference between bacteraemia and septicaemia?

Answer 3

• Bacteremia: microbes in the bloodstream

- Septicaemia: Hi # of microbes invading bloodstream quicker than it is removed by body

Question 4

Why do respiratory and genitourinary infections have a high predisposition for septicaemia?

Answer 4

Site where there’s
- mucous membranes (soft tiss) and vascular
=> easy to penetrate & get into blood

Question 5

Why is blood collected into two separate bottles for microbiological blood culture?

Answer 5

• Collecting more = inc chances of having a pathogen in sample
  [- also, 1st bottle usually collects contaminants (NF) ]

Question 6

Irrespective of the culture media type, what three characteristics would suggest positive growth in blood culture?

Answer 6

• Turbidity
• Gas build up
• Growth on slope
• Haemolysis of RBC

Question 7

What feature or occurrence would increase the likelihood of a CoNS being considered as a significant isolate in a blood culture?

Answer 7

• if both bottles in a set came out as positive =significant

- but if 1 bottle pos = likely NF

Question 8

In the coroner’s report, a) what claim was made regarding the blood cultures taken from the patient by PathWest? b) Later on during the afternoon of the 5th April, 2006 the doctors at the hospital were notified of a culture result, what was the culture result? c) What assumption was made by the doctor(s)? d) What did the evidence given to the inquest say about the significance of the culture result? e) Subject to the patient having any allergies to antibiotics, what antibiotic of choice could have been used to treat this infection?

Answer 8

a) Expired blood culture bottles
b) Positive blood culture
c) Dural tap for headache and involution pain for abdominal pain
d) Streptococcus or Enterococcus
e) erythromycin or 1GC