Microbiology Case Study Essay

You are working as an emergency room nurse in Topeka when a mother brings in her 8 year old son because of severe, bloody diarrhea. When questioned, the boy said that it hurts when he goes to the bathroom and his mother said he had vomited in the previous two days. When asked about their previous movements, the mother and son both mentioned a backyard barbeque that had taken place 6 days earlier. The boy complained that his mother made him eat a “pink” hamburger that was not thoroughly cooked.

A physical examination of the boy revealed nothing out of the ordinary except dehydration from the diarrhea. Lab tests showed that he had 13,000 white blood cells/microliter of blood, and a methylene blue stain of his feces showed abundant neutrophils. His stool specimen was plated on MacConkey agar and several colonies on the plate turned bright pink after 24 hours. Based on symptoms and the lab results, he was treated with trimethoprim-sulfamethoxadole and intravenous fluid therapy.

He improved quickly and was released after 24 hours.

1. What microbe is the most likely cause of the infection? Describe the clues you used to figure this out. (3 pts)The microbe most likely causing this infection is the parasite E. Coli. The uncooked hamburger can contain the E. Coli bacteria that comes from cows intestines. We already have E. Coli present in our intestines but large amounts of the bacteria can be toxic. According to the Mayo Clinic staff, symptoms of large amounts of E. Coli in the intestines include bloody diarrhea, abdominal cramping, pain, or tenderness, and nausea and vomiting. The 8 year old little boy showed all of these symptoms.

Sources:-Golder, Kim. Nurse Practitioner. Personal Interview. November 6, 2012.- “E. Coli.” Mayo Clinic. July 28, 2011. November 6, 2012.

2. Identify and describe one of the important virulence factors produced by the causative agent. (Hint: there is more than one right answer here!) How does this virulence factor contribute to the ability of the organism to cause disease? (3 pts)One important virulence factor produced by E. Coli is toxins. Toxins are proteins secreted by the bacteria that are poisonous to the host. In this case the toxins that are produced by E. Coli, damage the lining of the small intestine and that is what causes the bloody diarrhea. Sources:

-Leboffie, Michael J. Microbiology. Burton E. Pierce. Morton. Englewood, Co. 2012

3. Based on what you know about the selective and differential capabilities of MacConkey agar, would it be possible to obtain similar results from a stool sample of a health patient? Why or why not? (3 pts)The MacConkey agar is capable of growing E. Coli because it inhibits the growth of Gram-positive bacteria and E. Coli is a gram-negative bacteria. If we took a stool sample from a healthy patient the selective media would be similar because E. Coli always grows on a MacConkey agar and E. Coli is always present in the human intestines. However the differential media would not be similar because of the amounts of E. Coli in the intestines and also whether it is infectious or not. Different kinds of E. Coli have the ability or inability to ferment lactose which changes the colors of the dyes after the incubation period.

Sources:
-Leboffie, Michael J. Microbiology. Burton E. Pierce. Morton. Englewood, Co. 2012

4. How is this organism spread? How can infection be prevented? (3 pts)

According to the Mayo Clinic Staff, E.Coli is most easily spread through the consumption of food.In this case, the ground beef that the little boy consumed was contaminated with E. Coli. When cattle is slaughtered and processed some of the E. Coli from their intestines can contaminate the meat. Other food that can be contaminated with E. Coli is unpasteurized milk, fruits and other produce, and restaurant meals when servers and cooks do not wash their hands thoroughly after using the restroom. Sources:- “E. Coli.” Mayo Clinic. July 28, 2011. November 6, 2012.

5. Was antibiotic therapy an appropriate choice for this patient? Why or why not?
(3 pts)

Antibiotic therapy probably wasn’t the best choice for the little boy. When discussing the case with nurse practitioner, Kim Golder, she suggested that the best treatment for an E. Coli infection is to drink plenty of fluids so the patient doesn’t get dehydrated. She also suggested to get lots of bed rest and wait for the infection to subside.