A 38-year-old female is undergoing abdominal surgery. A foul-smelling abscess is encountered and a Gram stain of the abscess material reveals gram-negative rods. No growth is reported from aerobic microbiologic cultures. Which of the following organisms is MOST likely involved?
A) Staphylococcus epidermidis
B) Bacteroides fragilis
C) Escherichia coli
D) Bacillus subtilis