Nov 2011 Benchmark

Question 1

The proposed modified Duke system for evaluation/diagnosis of endocarditis in dogs- list the major and minor criteria.

Answer 1

Major Criteria
1) Positive echocardiogram for the below listed pathologies
a)Vegetative, oscillating lesion
b)Erosive lesion
c)Abscess

2) New valvular insufficiency or greater than trivial valvular insufficiency

3) Mild AI in absence of subaortic stenosis or annuloaortic ectasia

4) Positive blood culture
a)>/=2 positive sequential blood cultures with compatible agent for infective
endocarditis
b)>/=3 with common skin contaminant
c) persistent positive cultures over >/= 12 hours

Minor criteria
1) Predisposing heart condition (SAS)
2) Fever (>/= 39*C)
3) New or worsening heart murmur
4) Evidence of thromboembolic disease
5) Evidence of secondary immune mediated disease
6) Positive blood culture not meeting major criteria (e.g, 1 positive culture)
7) Bartonella serology > 1:1024

Diagnosis:

Definite: Pathology of valve or
2 major criteria or
1 major and 2 (or 3) minor or
5 minor

Possible
1 major and 1 minor or
3 minor

Question 2

What are the four most common infectious isolates noted in canine patients
with endocarditis?

Answer 2

Gram-positive bacterial organisms predominated in this population, as has been reported previously in dogs and people

Streptococcus spp., Staphylococcus spp, Gram negative rods (E.coli) and Bartonella sp.

Question 3

Describe
what is meant when an organism has intermediate sensitivity and give one instance
where a drug with intermediate sensitivity may be efficacious.

Answer 3

Intermediate sensitivity denotes a range of MICs where an organism may be sensitive
under some circumstances such as those drugs with flexible dosing or where drugs are
actively concentrated such as in urine.

Question 4

Imipenem is typically combined with cilastin. What is the purpose of cilastin?

Answer 4

Cilastin inhibits renal excretion of imipenem thus increasing drug levels.

Question 5

Define minimum inhibitory concentration:

Answer 5

The lowest drug concentration at which a microbe’s growth is inhibited.

Question 6

Define breakpoint:

Answer 6

The drug concentration at which a microorganism is no longer considered sensitive
to a given antibiotic, or the concentration at which an antibiotic is considered no
longer effective against a given microorganism.

Question 7

Describe the difference between concentration (dose) dependent and time
dependent antimicrobials and give an example of each:

Answer 7

Efficacy of concentration dependent drugs is determined by the peak drug
concentration in a 24-hour period.

Efficacy of time dependent drugs is determined
by the amount of time the drug concentration is above the MIC in a 24-hour period.

Concentration dependent: fluoroquinolones and aminoglycosides

Time dependent: all other classes

Question 8

List 4 strategies used by organisms to develop antimicrobial resistance:

Answer 8

a. Efflux pump
b. Change binding/action site on membrane
c. Destroy drug – secrete hydrolytic enzymes
d. Change cell wall permeability to drug – making impermeable

Question 9

What are three radiographic findings which could point AWAY from a patient’s respiratory signs being cardiac in origin?

Answer 9

No cardiomegaly
No pulmonary venous distention
No caudal vena cava distention

Question 10

List three pulmonary and three non-pulmonary causes of ARDS

Answer 10

Pulmonary – Pneumonia, pulmonary contusions, noxious gasses, volutrauma,
barotrauma

Non-pulmonary – Sepsis, pancreatitis, SIRS, non-cardiogenic edema (electric cord
shock, asphyxiation), heat stroke, envenomation