Case Study 3
Read the following case study and derive what you can to assist the patient. This should involve assessment of the facts, development of a hypothesis, and use of data to resolve the hypothesis. The logic you apply is more important than actually reaching the correct conclusion.
A 19-year-old outpatient male presented in the outpatient medical clinic for evaluation of diarrhea and abdominal discomfort. The patient first noted mild abdominal discomfort and three loose bowel movements per day1 week prior to evaluation. Two days prior to evaluation he noted intermittent, crampy periumbilical abdominal pain. He denied drinking well water, fever, blood in the stool, relation of pain to meals, dysuria, or hematuria.
On examination, the patient was afebrile and had normal vital signs. The abdominal examination was notable for mild lower abdominal tenderness. The fecal exam demonstrated a greenish, watery stool that was negative for occult blood.
Laboratory evaluation included a normal white blood cell count, hematocrit, and platelet count. Examination of the feces microscopically was remarkable for the presence of white blood cells. The organism causing his illness is shown in Figure 1 below (Gram stain) and Figure 2 (growth on chocolate agar). Attempts to grow the culture on Hektoen Enteric Agar and MacConkey Agar did not result in growth of the organism.
⦁ On the basis of the laboratory findings, what is the likely etiology of this patient’s diarrhea? Is the finding of white blood cells in the feces consistent with the recovery of this organism? Explain your answer.
⦁ What special laboratory and/or cultivation conditions are necessary to recover this organism?
⦁ What is the epidemiology of this organisms? What simple precautions can be taken to avoid its spread?
⦁ How have modern means of food production contributed to an increasing incidence of infections with this organism?
⦁ What is the current status of drug resistance in this organism? What factors are believed to play an important role in this status?
⦁ Although the patient has evidence of local invasion in the intestinal tract with this organism, bacteremia due to this organism is unusual. Explain this observation.
