The STAR-too study is a randomized, open label, multi-center study in CF patients with new MRSA isolated from the respiratory tract (sputum or oropharyngeal (OP) swab). The purpose of the study is to compare use of a two week eradication treatment protocol to an observational group treated for MRSA only when respiratory symptoms meet the criteria for a protocol defined pulmonary exacerbation during the first 28 days of the study. A total of 90 participants, four years of age or older, with new MRSA infection are planned to be randomized in a 1:1 fashion to either the treatment arm or to the observational control arm. Randomization is stratified by age, P. aeruginosa status at screening and site. Each participant randomized to the treatment arm receives two oral antibiotics for 14 days, topical antibacterial treatment of skin and nares, and a three week environmental decontamination for high risk areas and equipment. Each participant randomized to the observational control arm is followed clinically with usual care except to treat new or worsening pulmonary symptoms with antibiotics between screening and Day 28 only when participant meets criteria for a protocol defined exacerbation. Participants continue in the study for 6 months with study visits at Day 84 and Day 168 corresponding with their normal quarterly visits, this extension of observation provides additional data regarding natural history of MRSA infection and durability of the eradication protocol. The primary outcome is the proportion of participants with MRSA eradicated from respiratory tract cultures at Day 28. The secondary outcomes number of, and time to, pulmonary exacerbations, and use of antibiotics.