A 28-year-old woman patient who is 13 weeks pregnant presents for an antenatal clinic appointment. The patient feels embarrassed when asked to provide a urine sample and produces enough for a urine dipstick test only which is positive for leukocytes and nitrites. The patient denies any symptoms. The most appropriate treatment is:

The treatment of symptomatic and asymptomatic bacteriuria is impoant to prevent complications in pregnancy. Empiric treatment for common organisms such as Escherichia coli and Proteus should be administered while maintaining safety. Penicillins and cephalosporins, such as cephalexin (D), are safe for use during pregnancy. Nitrofurantoins are also effective. Trimethoprim (A) is a folic acid antagonist and therefore should be avoided in pregnancy, especially in the first trimester of pregnancy as in this patient. Fluoroquinolones (B) and tetracyclines (C) are also known teogens and must also be avoided in pregnancy.