Unclean and uncaring nurses in the U.K. are blamed may have spread superbugs that led the deaths of the patients they were charged with caring for.

The nurses are accused of not washing their hands and of leaving patients lying in soiled beds. They were cited in an official report blaming mismanagement for the deaths of 90 people who contracted a bacterial infection in hospitals in southern England.

"Significant failings" at all levels contributed to infections of more than 1,000 patients at three hospitals, the Healthcare Commission said Thursday.

The patients were infected with Clostridium difficile, or C. diff, which can cause diarrhea, colitis and other intestinal problems, officials said.

"The Healthcare Commission has passed the copy of the report to us and that is being reviewed," said a spokesman for Kent Police, speaking on condition of anonymity in line with force policy.

The report into the spread of the highly contagious bacterium said nurses at three hospitals run by the Maidstone and Tunbridge Wells NHS trust were often too busy to wash their hands and left patients in their own excrement.

Maidstone and Tunbridge Wells NHS trust acknowledged that it had not been prepared for "an outbreak of that size and complexity" but had learned from the mistakes.

The trust's Chief Executive Rose Gibb resigned last week.

Health Minister Ann Keen said the failures, which led to the deaths of patients over a 2 1/2-year period, must not be repeated.

"Trusts must deliver clean, safe treatment to every patient, every time and where senior management and trust boards fail to act, they must be held accountable," Keen said.

Investigations began after a series of complaints about cleanliness, and when the trust claimed there had been no deaths from the bug despite admitting there had been hundreds of cases.

The trust has also introduced extra cleaners and nurses on affected wards and asked family doctors not to send patients with diarrhea to hospital, measures that will continue until the outbreak ends.

In recent years, Britain's superbug infection rates of bacteria like Clostridium difficile and MRSA have skyrocketed. In the 1990s, only 5 percent of in-hospital blood infections were from MRSA, the deadly bacteria resistant to nearly every available antibiotic. In past years, that figure has jumped to more than 40 percent. Critics blame the rise on overstretched hospitals that do not have enough money or capacity to catch superbug infections early.

The Associated Press contributed to this story