A new superbug that is resistant to even the most powerful antibiotics has entered UK hospitals, experts warn.

They say bacteria that make an enzyme called NDM-1 have travelled back with NHS patients who went abroad to countries like India and Pakistan for treatments such as cosmetic surgery. Although there have only been about 50 cases identified in the UK so far, scientists fear it will go global. Tight surveillance and new drugs are needed says Lancet Infectious Diseases.

NDM-1 can exist inside different bacteria, like E.coli, and it makes them resistant to one of the most powerful groups of antibiotics - carbapenems. And experts fear NDM-1 could now jump to other strains of bacteria that are already resistant to many other antibiotics.

Ultimately, this could produce dangerous infections that would spread rapidly from person to person and be almost impossible to treat.

Similar infections have been seen in the US, Canada, Australia and the Netherlands and international researchers say that NDM-1 could become a major global health problem.

The way to stop NDM-1, say researchers, is to rapidly identify and isolate any hospital patients who are infected.

He said the threat was a serious global public health problem as there are few suitable new antibiotics in development and none that are effective against NDM-1.