Two consecutive urine cultures have reported staph epi 100,000. The sensitivities included Bactrim (sulfa allergy), erythomycin, and the remaining drugs were IV cephlosporins, and vancomycin. Two different docs (one urologist and one nephrologist) ordered po Keflex and one added Flagyl due to recent history o C. diff. Their reasoning was that Keflex is a cephlosporin so it should work. The PCP claimed it was a contaminant even with 100,000 colonies. Will the Keflex be effective?