You may use your textbook and outside sources. If you refer to outside sources, please provide the source of your information as a citation at the end of your answer. Write out your answers in a Word document in paragraph form, numbering each answer that corresponds to the case, and post your solutions to the discussion board. Remember to include the clues and facts you used to solve the puzzles.
1. In this case history, a 49 year-old man handled a parakeet with a respiratory illness on February 7. On March 9, he experienced intense pain in his legs, followed by severe chills and headaches. On March 16, he had chest pains, cough, and diarrhea, and his temperature was 40°C. Appropriate antibiotics were administered on March 17, and his fever subsided within 12 hours. He continued taking antibiotics for 14 days. Identify each period in the pattern of disease that he experienced. Note: The disease is psittacosis. Can you find the etiology?
2. Mycobacterium avium-intracellulare is prevalent in AIDS patients. In an effort to determine the source of this infection, hospital water systems were sampled. The water contained chlorine. What is the usual method of transmission for Mycobacterium? What is the probable source of infection in hospitals? How can such nosocomial infections be prevented?
Percentage of samples with M. avium
Hot water Cold water
February 88% February 22%
June 50% June 11%
3. Twenty-one percent of the patients in a large hospital acquired Clostridium difficile diarrhea and colitis during their hospital stay. Epidemiological studies provided the following information. What is the most likely mode of transmission of this bacterium in hospitals? How can transmission be prevented?
Rate of infection for patients:
Single room 7%
Double room 17%
Triple room 26%
Rate of environmental isolations of C. difficile:
Bed rail 10%
Commode 1%
Floor 18%
Call button 6%
Toilet 3%
Hands of hospital personnel after contact with patients that were culture-positive for C. difficile:
Used gloves 0%
Did not use gloves 59%
Had C. difficile before patient contact 3%
Washed with nondisinfectant soap 40%
Washed with disinfectant soap 3%
Did not wash hands
