Scientists have identified an emerging “superbug” strain of salmonella that is highly resistant to the antibiotic Ciprofloxacin, or Cipro, often used for severe salmonella infections, and say they fear it may spread around the world. The strain, known as S. Kentucky, has spread internationally with almost 500 cases found in France, Denmark, England and Wales in the period between 2002 and 2008, according a study in the Journal of Infectious Diseases. French researchers who led the study also looked at data from North America and said reports of infection in Canada and contamination of imported foods in the United States suggest the strain has also reached there.