Exam 11: Travelers Diarrhea: Identifying the Causative Agent

What is the defect in a 5-year-old boy with chronic granulomatous disease?

A 17-year-old girl presents to your gynecology clinic with complaints of recurring pelvic pain. A probable diagnosis of pelvic inflammatory disease is made. She is a senior at a suburban high school, is involved in orchestra, and has been on the honor roll most years. She does not do drugs. She has had an equally "squeaky clean" type of boyfriend since last fall, and 6 months ago they had unprotected sex on three occasions. What is the most likely causative agent?

An 80-year-old woman is referred to your cardiac practice with no fever but worsening exertional fatigue. She has had a heart murmur since she was young. It appears to have worsened recently. At her 80th birthday party 4 weeks ago, two of her great nieces were sick, and she thinks she picked up their sore throat. She was sick with fever for about a week 3 weeks ago but did not have enough energy to go to the doctor. If you did standard bacterial blood cultures, what would be the most likely outcome?

What respiratory infection is known to increase susceptibility to pneumonia caused by Streptococcus pneumoniae?

A 30-year-old woman presents with an inflamed, itchy, expanding cutaneous lesion on her side. She suspects she might have picked it up from her dog because it is where the dog sleeps next to her and the dog is losing fur. (The dog also needs to be treated by the vet.) You treat the woman with a topical drug from one of the major drug families commonly used to treat the infection. What is the mechanism of action of that drug class?

Your patient presents with recurring pain suggestive of a duodenal ulcer and is positive for antibodies against Helicobacter pylori. What allowed H. pylori to survive the transit through the gastric lumen to start the infection?

What compound is only found in Gram-positive bacteria?

Two physicians traveling in Central America develop what they self-diagnose as ET Escherichia coli. What is responsible for the fluid and electrolyte disruption?

While playing in the forest, a 13-year-old boy was bitten in the lower left leg by a raccoon. What finding would suggest a serious neurologic disease could result from the bite?

A 63-year-old alcoholic presents complaining of chest pain, fever, shaking chills, cough, and myalgia. She was very cold two nights ago and says she has felt "poorly" ever since. Her cough is producing rust-colored, odorless, mucoid sputum. Her temperature on admission is 40°C. Her white blood cell count is 16,000 cells/mm3 and is predominantly neutrophils with an overall left shift. An $\alpha$ -hemolytic, lancet-shaped, Gram-positive diplococcus is isolated on blood agar. What is the most likely causative agent?

CD8 is a surface membrane protein on T cells, which has the following characteristic.

In a high-frequency recombination (Hfr) cross with an $F^-$ bacterial cell, each having a single DNA molecule, what is the most likely outcome?

An emerging pathogen has been associated with serious lower respiratory tract disease. Both amprenavir and saquinavir have been demonstrated to be effective in treating the infection. What step in the pathogenesis of the infectious agent is affected by these drugs?

A 35-year-old male AIDS patient is hospitalized with a serious pneumonia. His x-ray shows an interstitial pattern of infection, and lab analysis of his sputum indicates the presence of giant cells. Which drug is the best one to be utilized to treat this infection?

Following a 12-year-old girl's birthday party, which took place in her backyard and involved summer sport games and swimming, several parents complained that their children developed red, watery, and slightly itchy eyes; a sore throat; and a slight fever. The children's eyes were examined and no petechial hemorrhages were observed, but preauricular adenopathy was present. What is the most likely causative agent?

What autoimmune disease is characterized by antibodies against intrinsic factor?

In addition to IL-1, which of the following is an inflammation-inducing cytokine?

A sexually transmitted disease with no genital signs or symptoms is

A patient with severe burns that have become infected with Pseudomonas aeruginosa has a circulating exotoxin whose activity is similar to what other organism's exotoxin?

After extensive oral surgery, a 68-year-old patient who had rheumatic fever as a child and who did not take the prescribed perioperative prophylactic antibiotics subsequently developed subacute infective endocarditis. Which of the following is the most likely causative agent?