A 35-year-old woman presented to the oral surgeon with an extremely painful molar tooth and a swollen gum. She reports that the area "tastes bad." She has a fever, and the area is tender to the touch.

The surgeon drained the area of several milliliters of foul-smelling pus which was sent to the lab for aerobic and anaerobic culture and Gram stain.

1. Which of the following represents the expected Gram stain report?

A . WBCs and gram-positive cocci
B . WBCs and gram-negative rods
C . WBCs and a mixture of organisms
D . No WBCs seen, no organisms seen

2 . Which of the following represents the expected culture report?

A . Pure culture of Staphylococcus aureus
B . Pure culture of Streptococcus pyogenes
C . Mixed organisms representing normal oral microbiota
D . Mixed aerobic and anaerobic organisms

3. What is the usual treatment for this type of infection?

A . Surgical debridement and broad-spectrum antibiotics
B . Penicillin
C . Amoxicillin
D . None is required for normal organisms

4 . For what organism may the surgeon be particularly concerned if the infection appeared to be spreading through "sinus tracts"?

A . Actinomyces israelii
B . Streptococcus pyogenes
C . Escherichia coli
D . Bacteroides fragilis

5 . Why is this organism (#4) of concern?

A . It is notoriously resistant to antibiotics
B . It requires prolonged antibiotic therapy
C . It is highly contagious
D . It is pigmented