My wife is 3 days in to a 7 day, twice daily dose of Bactrim for a Staph infection. Her doctor sent a biopsy sample from her open, oozing sore, but started her on this, for now, until he learns if a more specific antibiotic is preferred for her type of Staph. My wife is experiencing constipation rather than any diarreah, is that also an occasional, if less common side effect??