Trimethoprim alone for treatment of urinary tract infection.

Studies of the use of trimethoprim (TMP) alone compared with the use of trimethoprim and sulfamethoxazole in combination (TMP-SMZ) have shown that TMP alone is as effective as TMP-SMZ in the treatment of urinary tract infections. With the exception of one study in which use of TMP singly for 28 days for treatment of recurrent urinary tract infections selected resistant nonfermenting bacteria, the use of TMP singly for treatment of urinary tract infections has not resulted in selection of resistant Enterobacteriaceae. However, use of both TMP and TMP-SMZ for prevention of traveler's diarrhea has resulted in plasmid mediated resistance in Escherichia coli.