Today, "S. aureus" has become resistant to many commonly used antibiotics. In the UK, only 2% of all "S. aureus" isolates are sensitive to penicillin, with a similar picture in the rest of the world. The β-lactamase-resistant penicillins (methicillin, oxacillin, cloxacillin, and flucloxacillin) were developed to treat penicillin-resistant "S. aureus", and are still used as first-line treatment. Methicillin was the first antibiotic in this class to be used (it was introduced in 1959), but, only two years later, the first case of methicillin-resistant "Staphylococcus aureus" (MRSA) was reported in England.