CASE HISTORY 3

A 39 year old black female was admitted with low grade fevers, weight loss, and malaise which has been ongoing for three weeks. Her past medical history is significant for chronic renal failure secondary to postpartum complications. She has an A-V fistula in her right arm through which she receives her weekly dialysis. Blood cultures were drawn over the first 24 hr of her admission. Her physical exam revealed a grade III/VI diastolic murmur, which was not present on previous exams. Within 36 hr. the aerobic and anaerobic bottles of all three sets of blood cultures turned positive. The Gram stain of the blood culture was read as Gram positive cocci in pairs and short chains. The patient was empirically treated with ampicillin and gentamicin, but she remained culture positive. Vancomycin was added to her regimen, but she did not improve. 

1. What infectious disease does this woman have?   Answer

2. What is the pathogenesis of this disease?  Answer

3. What signs and symptoms would you look for to verify your diagnosis?  Answer

4. How would you confirm the presence of vegetations on heart valves?  Answer

5. The microbiology lab reports that colonies growing on a blood agar plate are catalase negative, nonhemolytic, and stain as Gram positive cocci in chains. The colonies are bile esculin positive and PYR positive. Based on the laboratory data, which microorganism is the most likely pathogen?  Answer

6. Why is this patient failing to improve on her antibiotics?  Answer

7. What predisposed this patient to acquiring an infection with this bacterium?  Answer

8.What other infections are commonly caused by this group of organisms?  Answer

9.What infection control precautions must be taken for this patient?  Answer