Merck ($MRK) is launching Sivextro, the newly approved antibiotic it picked up in its $9.5 billion buyout of Cubist, in the U.K. Pharmafile reports it is the first oral treatment to be released in the oxazolidinone class of antibiotics in more than a decade. It is approved to treat acute bacterial skin and skin structure infections (ABSSSI), which are often caused by the MRSA superbug. Story