A 24-year-old Woman complains of dysuria, hesitancy in urination, and frequent urination for the past 2 days. She has no costovertebral tenderness, fever, or history of UTls. Urinalysis data are:
* pH: 5.5
* WBCS: 15 cells/ul
* RBCS:5 Cells/uL
* Bacteria: Numerous Gram-negative rods
* Negative for protein, glucose, and WBC casts
For this patient, assuming that local resistance rates are low, which of the following would be an empiric cost-effective regimen?