A 3-week-old baby boy is brought to the emergency department with fever, irritability, and poor feeding. Examination of the cerebrospinal fluid shows a leukocyte count of 600 cells/µL (80% neutrophils), protein of 160 mg/dL, and glucose of 20 mg/dL. Blood cultures grow gram-negative rods that form pink colonies on MacConkey agar. Which of the following is the most important bacterial virulence factor for the development of this patient's condition?

Question

A 3-week-old baby boy is brought to the emergency department with fever, irritability, and poor feeding.  Examination of the cerebrospinal fluid shows a leukocyte count of 600 cells/µL (80% neutrophils), protein of 160 mg/dL, and glucose of 20 mg/dL.  Blood cultures grow gram-negative rods that form pink colonies on MacConkey agar.  Which of the following is the most important bacterial virulence factor for the development of this patient's condition?

Quizplus · Accepted Answer

Eductional Objective: Escherichia coli is a frequent cause of neonatal meningitis, second only to group B streptococci.  E coli strains that cause neonatal meningitis possess the K1 capsular antigen.  The K1 capsule is a virulence factor that allows the bacteria to survive in the bloodstream and establish meningeal infection.

A 3-Week-Old Baby Boy Is Brought to the Emergency Department