A deadly, drug-resistant bacteria linked to contaminated tools used by doctors has infected scores of people in the USA.

The nation’s Food and Drug Administration has warned that a total of 179 patients may have been exposed to a ‘super bug’ called CRE through scopes used in many hospital procedures.

Seven patients of the Ronald Reagan Medical Centre in California have been confirmed infected, and two have died.

• Kids shorter, fatter because of junk food diets
• Government to you: start lifting your weight!
• Hep A scare: buy local to avoid virus-laced berries

An additional 135 people were infected at other US hospitals in 2013 and 2014, the FDA said, in cases that may also be linked to contaminated scopes.

CRE is short for carbapenem-resistant Enterobacteriaceae, which the US Centre for Disease Control calls a “nightmare bacteria”.

Doctors can do little to help patients infected by super bugs, as most antibiotics do not work. Photo: Getty

Related to the better-known E coli, it kills up to half of infected patients because it is resistant to last-resort carbapenem antibiotics and can spread unchecked.

The bacteria spreads through direct contact, such as that between an improperly disinfected medical instrument and bodily tissue.

The bug was discovered in one US hospital in 2001, and by 2013 had spread to hospitals in 46 of 50 US states.

The scope in question is inserted down the gastrointestinal tract in a procedure to examine and treat pancreatic disease.

About half a million Americans undergo the procedure each year, according to the FDA.

In a statement, the hospital said it had disinfected the scopes according to manufacturer instructions, but since the infections were discovered had instituted new, more stringent procedures.

Bacteria develop resistance to antibiotics through continued exposure, a phenomenon public health experts blame on misuse of the drugs, including doctors who prescribe unnecessary antibiotics and patients who take them improperly.

In a 2014 report on antimicrobial resistance, the World Health Organisation (WHO) said carbapenem antibiotic resistance has spread to all areas of the world.

The WHO warned that without immediate coordinated action, “the world is heading toward a post-antibiotic era, in which common infections and minor injuries which have been treatable for decades, can once again kill”.

University of Adelaide Professor John Turnidge previously told The New Daily that “our backs are against the wall” if superbugs multiply.

“We’ll have to use our last line antibiotics or even go further and dig up some ones that we discarded 30 or 40 years ago because we thought they were too toxic,” Professor Turnidge says.

—with AAP.