4/4 Professor Hugh Pennington at Aberdeen University has studied the bacteria Staphylococcus aureus since the 1960s, and was himself infected with it in his nose during an outbreak that swept through British hospitals at that time. it's now better known as MRSA, the superbug that has evolved resistance to most antibiotics. Pennington tells Jolyon Jenkins about the series of mistakes that turned a common or garden bug into a major health threat. Forfurtherdetailssee Tuesday