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Chapter 74. Infective Endocarditis

Student Questions

Which of the following statements is false regarding IE?

A. Coagulase-negative staphylococci are the predominant organism causing PVE.

B. Patients with HACEK organisms present acutely.

C. IVDUs are at an increased risk of developing IE caused by less common organisms.

D. A patient has an increased risk of culture-negative IE with recent antimicrobial exposure.

Answer: B

Option A: Incorrect. Coagulase-negative staphylococci are the most common causative organism in PVE.

Option B: Correct. Patients with a HACEK organism are most likely going to present as a subacute disease, often taking weeks to progress in severity.

Option C: Incorrect. Use of illicit IV drugs expands the potential causative organisms, particularly to gram-negative bacterial pathogens.

Option D: Incorrect. Prior use of antibiotics interferes with growth of organisms in culture, particularly blood cultures since most drugs achieve serum concentration typically greater than the MIC of the pathogen.

Which of the following signs/symptoms would likely be from a patient presenting with Streptococcus mitis IE?

A. Fevers of 102°F (38.9°C) and chills

B. Patient complaints of recent illness only over the past week

C. A weight loss of 15 pounds (6.8 kg) in past month

D. Patient has small, painless, hemorrhagic lesions on the palm of the hands

Answer: C

Option A: Incorrect. High fevers are more indicative of acute infection such as with staphylococcal IE.

Option B: Incorrect. Typically complaint of illness for such a short period of time is more commonly associated with organisms causing acute disease, not subacute disease which is more typically seen with Streptococcus mitis.

Option C: Correct. Streptococci usually cause subacute disease, progressing over weeks to months before presentation to the hospital.

Option D: Incorrect. The lesions described on the hands are consistent with Janeway lesions, which are more commonly associated with acute S. aureus infections.

Which of the following statements regarding treatment considerations is true?

A. Combination therapy is needed against all gram-positive bacteria.

B. Antimicrobial efficacy is affected by the amount of bacteria within the vegetation.

C. Surgery is only required in patients who have prosthetic valves.

D. Newer agents should ...

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