Nothing grew in my sputum samples. Bactrim is a broad spectrum antibiotic to treat the sinus infection. Unfortunately, I’m allergic to penicillin. So far I’ve been on it for 3 weeks with absolutely no problems. I take it twice a day with a meal and a probiotic in between doses. My gastroenterologist recommended Endomune Probiotic and told me to take it for two months following treatment. I also have been told by two of my doctors to drink a lot water while on this medication.