A genetic analysis of about 300 samples of Clostridium difficile bacteria collected from around the world found that the global outbreaks were in fact caused by two different strains that had independently acquired resistance to an antibiotic widely used in hospitals.
Scientists traced the evolutionary trees of each strain of C. diff and found that both originated within a couple of years of each other, one in a hospital in Pittsburg, Pennsylvania, and the other in Montreal, Canada.
International travellers carried the Canadian strain to Britain and the rest of Europe, where it caused a notorious series of outbreaks in UK hospitals between 2003 and 2006, leading to hundreds of patients dying from bowel complications.
