Mrsa test came back negative, but may be false neg. how soon can someone retest if they were on bactrim (sulfamethoxazole and trimethoprim) and topical antibiotics prior to test/culture?

Negative MRSA: We usually hope after treatment with Bactrim (sulfamethoxazole and trimethoprim) / topical antibiotics that we have eliminated MRSA, so retesting 3-5 days after stopping antibiotics should yield a negative result. If one is a carrier you test the nasal swabbings for MRSA. That requires longer term -6 weeks for intranasal mupirocin as treatment . Also sometimes house pets can be carriers and repeatedly infect their owners.