Question

A 4-year-old male was admitted to the hospital with vomiting, prolonged bloody diarrhea, abdominal cramping and recent anuria. The patient appeared pale and his vital signs indicated he was hypertensive. Upon questioning, the boy’s father reported that their family had experienced acute self-limiting diarrhea earlier this week. The physician ordered a stool culture and the following laboratory results were reported three days later:

Direct Stool exam:

Fecal leukocytes: Negative

Stool Culture: Negative for Salmonella, Shigella, and Campylobacter species

The physician ordered a CBC and noticed that the boy was anemic. He also had a low platelet count and his white blood count was increased. The physician diagnosed the boy with Hemolytic Uremic Syndrome.

Question:

a. What enteric pathogen would you suspect to be responsible for this condition? What virulence factors are responsible? (2 points)

Question:

b. What is the most likely source of this pathogen? (2 point)

Question:

Why was the culture negative for this organism? What should be completed to confirm the causative pathogen? (2 points)

Answer 1

Hemolytic uremic syndrome :

Hemolytic uremic syndrome is a clinical syndrome that affects blood and blood vessels.

It is characterized by destruction of red blood cells , low platelet count followed by kidney failure .

a) The enteric pathogen responsible for hemolytic uremic syndrome is shiga toxin producing E.coli.

Among the many serotypes of E.coli , the STEC ( shiga toxin producing E.coli ) 0157 is common cause of Hemolytic uremic syndrome.

b)It is a water borne pathogen .The main sources of this pathogen is

• Contaminated vegetables
• Undercooked ground beef
• Faecally contaminated lakes
• Consumption of contaminated water
• Person to person transmission.