Microbiology Fundamentals 2nd Edition by Jennifer Bunn,Marjorie Kelly Cowan

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C A S E F I L E

Leona's Beloved Cheese
While I was in nursing school, I was working as a nurse's aide in a long-term care facility. One of my favorite patients was Leona. She was 88 years old and generally healthy, though frail. She loved to tell stories of her youth in Mexico in the 1930s and 1940s before she immigrated to the United States. She spent the first 3 weeks of August looking forward to a visit from her extended family during their family reunion, which was being held locally.
The family visit came and went, and Leona talked about this cousin or that nephew for days afterward. One day when I checked in on Leona at the beginning of my shift, she was quite ill. As soon as I walked into her room, she leaned over the side of the bed to vomit, and I immediately detected the telltale odor of diarrhea. Then she began to cry. She was a mess. I called for a doctor and cleaned her up. I tried to comfort her, but she was cramping and experiencing severe pain. When the doctor arrived, she ordered rehydration and stool cultures and tried to make Leona comfortable. Then she questioned Leona about possible exposures. Because Leona never leaves the facility, we were worried that she had acquired an infection there. We needed to know how it was transmitted. Different measures would need to be taken if it was from the environment, from a caregiver, or from food, for example. Any of those possibilities suggested that more residents could be affected.
Eventually, the doctor established that her family had brought some of her favorite delicacies to her from their large spread of food at the reunion. One of her favorite foods was queso blanco, a Mexican cheese made from unpasteurized milk. The family had brought her a large plate of it, and she had eaten it 3 days previously. Upon questioning, the family revealed that two other people had reported mild GI tract symptoms as well but that dozens of people at the reunion had eaten the cheese.
Leona's stool cultures came back positive for Campylobacter. The doctor said she was fairly certain that the queso blanco was the culprit and that we should have no further cases of diarrhea at the facility.
• If the source of Campylobacter was, indeed, the cheese, why did only three people (of dozens) become ill?
• Why is most milk in the United States pasteurized?