A 24-year-old woman is managed in hospital for ruptured appendicitis and sepsis. Blood pressure is stable. Exploratory laparoscopy shows a collection of pus. Gram stain shows neutrophils, gram-positive rods, gram-positive cocci, and gram-negative rods. Aerobic culture on MacConkey agar plates yields Enterococci. Which of the following bacteria is most likely to be among the gram-negative rods?
Bacteroides fragilis
E. coli
Legionella pneumophilia
Moraxella catarrhalis
Proteus mirabilis
