Case Study Exercise 4
EXAMPLE: Sarah, a 19-year-old female has a history of a urinary tract infection (UTI) 4 months prior to admission for which she was treated with oral ampicillin without complications. Five days prior to this admission, she began to note nausea without vomiting. One day later she developed left flank pain, fevers and chills, and increased urinary frequency. Sarah noted foul-smelling urine on the day prior to admission. She presents with a temperature of 101.8o F, and physical examination shows left costovertebral angle tenderness. Urinalysis of a clean-catch urine sample is notable for >50 white blood cells per high-power field, 3 to 10 erythrocytes per high-power field, and 3+ bacteria. Urine culture is subsequently positive for >100,000 CFU of a Gram negative, lactose-fermenting rod per ml; this bacterium was indole positive.
E1. What do the urinalysis findings indicate? Explain your answer. The bacterium responsible for the infection is the most common cause of UTI’s: What is the pathogen?
E2. How do the biochemical reactions help in the diagnosis?
E3. Why are urinary tract infections more common in women than in men? Did this woman have cystitis or pyelonephritis? Why is it important to differentiate?
A. 48-year-old Timothy has a long history of alcoholism (including alcoholic hepatitis and hallucinosis) and was admitted to the intensive care unit with profound hypotension and gastrointestinal bleeding. He was intubated and given IV fluids and transfused with packed erythrocytes. He remained intubated and ventilator-dependent for several weeks. He developed fevers and was treated with broad-spectrum antibiotics. Culture of his tracheal aspirate initially showed Staphylococcus aureus. After further antibiotic therapy, Gram stain of Tim's tracheal aspirate showed polymorphonuclear leukocytes and Gram negative rods. His chest radiograph demonstrated an infiltrate and changes consistent with multiple small abscesses. Culture of the tracheal aspirate yielded a heavy growth of an oxidase-positive, beta-hemolytic, lactose nonfermenting rod that produced a greenish hue on the culture plates.
1. What is the likely agent of infection?
2. This organism produces an exotoxin that is similar to the exotoxin of which other bacteria? How do these toxins act on host cells?
3. This organism was isolated after Tim received a prolonged course of broad-spectrum antibiotic. Where is the organism usually found in hospitals? Does it usually cause pulmonary infections in healthy individuals?
4. What is wrong with Harvey? Explain your reasoning.
5. What environmental source is associated with the organism and why?
6. Name two states in the U.S. where it is endemic.
7. What is the etiologic agent causing Cathy's disease?
8. How is this transmitted?
9. How might this be prevented?
10. What is the most likely culprit (genus and species)? Support your answer!
11. If the Sara had “rice water stools,” what species would you suspect? Support your answer.
12. How are these diseases prevented? Be very specific.
13. How would you treat Valerie and why?
14. Is there a current vaccine? Explain the recent history of the vaccine.
15. Compare and contrast incidence statistics of the U. S. and the developing world.
16. What is the disease? Explain your reasoning.
17. What is Edith's prognosis?
18. What causes the symptoms?
19. Are other patients at risk of transmission from Edith? Explain your reasoning.
20. How is this disease prevented? Be very specific about the timing.