A 6-day-old female infant is brought to the emergency department because of poor feeding and irritability for two days. She was born at 39 weeks' gestation, and the pregnancy and delivery were uncomplicated. Her temperature is 39.2°C (102.6°F). She appears lethargic and makes occasional twitching movements in both upper extremities. The anterior fontanelle is soft and full. Empiric cefotaxime and vancomycin therapy is initiated. A lumbar puncture is performed and analysis of the cerebrospinal fluid shows increased protein and decreased glucose. Cerebrospinal fluid culture shows an organism that is resistant to cefotaxime. Which of the following organisms is most likely causing this patient's infection?

Question

A 6-day-old female infant is brought to the emergency department because of poor feeding and irritability for two days. She was born at 39 weeks' gestation, and the pregnancy and delivery were uncomplicated. Her temperature is 39.2°C (102.6°F). She appears lethargic and makes occasional twitching movements in both upper extremities. The anterior fontanelle is soft and full. Empiric cefotaxime and vancomycin therapy is initiated.  A lumbar puncture is performed and analysis of the cerebrospinal fluid shows increased protein and decreased glucose. Cerebrospinal fluid culture shows an organism that is resistant to cefotaxime.  Which of the following organisms is most likely causing this patient's infection?

Quizplus · Accepted Answer

Eductional Objective: Ampicillin is the treatment of choice for Listeria, which is not sensitive to cephalosporins.  Listeria most commonly causes disease in those with deficient cell-mediated immunity, such as young infants or immunocompromised patients.

A 6-Day-Old Female Infant Is Brought to the Emergency Department