A 37 year old man develops a recurrent episode of pseudomembranous colitis shortly after completing an initial course of oral metronidazole therapy. Which of the following best explains the recurrence? The bacterial strain can form spores that persist in the gastrointestinal tract Other gastrointestinal flora have degraded the metronidazole The patient has an underlying gastrointestinal tract disorder Systemic therapy is necessary to eradicate this infection

A 37 year old man develops a recurrent episode of pseudomembranous colitis shortly after completing an initial course of oral metronidazole therapy. Which of the following best explains the recurrence? The bacterial strain can form spores that persist in the gastrointestinal tract Other gastrointestinal flora have degraded the metronidazole The patient has an underlying gastrointestinal tract disorder Systemic therapy is necessary to eradicate this infection