Listeria Infection in Pregnancy

A Case Study

A pharmacist's wife I had been caring for came in for a routine visit at about 37 weeks. She claimed some vague change in fetal movement had occurred. The ultrasound didn't show anything worrisome, but just to be ridiculously (I thought) overcautious, I had her undergo a fetal non-stress test. The test was somewhat reassuring, but not perfect, so I sent her to the hospital for a contraction stress test. With each contraction induced, there was a deceleration of the fetal heart rate. More alarmingly, it was what is called a late deceleration, indicating that not only did the baby not have a lot of reserve for stress, but also was delayed in reacting to stress, indicating fetal distress and that the baby could not tolerate a labor.

At the mother's C-section, there was a lower than normal Apgar score, but it improved at five minutes and the baby ultimately did fine. I obtained cultures on both sides of the placenta at the time of surgery, and the results grew out listeria. Mom and Dad gave me a ceramic angel to hang up in our non-stress test exam room, where I always think about listeria when things aren't quite right.

Preventing Listeria Infection

By following these food safety guidelines, pregnant women and at-risk people can avoid risk of listeria infection:

• Do not eat hot dogs, deli meats or luncheon meats unless they are heated to steaming.
• Do not eat soft cheese such as feta, Brie, Camembert, blue-veined cheeses, and Mexican-style cheeses such as "queso blanco fresco."
• You can safely eat hard cheeses, semi-soft cheeses such as mozzarella, pasteurized processed cheese slices and spreads, cream cheese, and cottage cheese during pregnancy.
• Do not eat refrigerated smoked seafood (unless it is an ingredient in a cooked dish) including salmon, trout, whitefish, cod, tuna, and mackerel which are most often labeled as nova-style, lox, kippered, smoked, or jerky. This fish is found in the refrigerated section or at the deli.
• You can safely eat canned or shelf-stable pâté and meat spreads. Additionally, canned fish such as salmon and tuna or shelf-stable smoked seafood may be safely eaten.
• Do not drink raw (unpasteurized) milk or eat foods that contain unpasteurized milk.