By Michelle Fay Cortez - 2012-08-23T04:01:00Z

Scientists using rapid genetic testing to track the path of a deadly bacterium in a Maryland medical center discovered unsuspected ways pathogens can spread and learned a new tool to combat hospital-acquired infections.

The DNA screening allowed staff at the National Institutes of Healths research hospital in Bethesda, Maryland, to link infections with a multidrug resistant strain of Klebsiella pneumoniae weeks after the first case was found, even though there were no obvious ties among the patients. Uncovering the way the bacteria moved silently though the hospital for weeks confirmed an outbreak was under way and prompted aggressive measures to control the pathogen that infected 18 people.

This has changed the practice of medicine in our hospital and we hope it will change the way other hospitals would control a similar outbreak, said Julie Segre, a senior investigator at the National Human Genome Research Institute.

Advances in genetic sequencing allowed researchers to map minute differences in the DNA of the bacterium in less than a week, proving all 18 cases began with a single patient in June 2011.

The first patient, a 43-year-old New York woman, was isolated as soon as she arrived at NIHs 243-bed hospital in Bethesda. Infection-control procedures, such as gloves and gowns for all staff and visitors, were used to contain the dangerous bacteria.

The effort was unsuccessful. Seventeen other patients subsequently fell ill, at an alarming rate of one a week. Eleven people died, six from K. pneumoniae and five from underlying diseases that were exacerbated by the bacteria, which evaded all commonly used antibiotics, including carbapenem, one of the most potent germ-killers.

Its an emerging pathogen, but weve never had a patient with it in our hospital or in this area that we were aware of, Segre said.

Hospital-acquired infections arent new, occurring in more than 1 million patients each year in the U.S. The mystery of the K. pneumoniae case, detailed yesterday in the journal Science Translational Medicine, arose because the second case of infection didnt emerge until three weeks after the first patient was treated and discharged. The bacteria turned up in a trachea of an immune-compromised patient, who had never been in the same hospital ward as the woman from New York.

After the first patient was released, we did routine surveillance to see if anyone in the hospital was exposed and the tests came back negative for weeks, Segre said. On August 5, we got our second patient with a Klebsiella infection. We were stunned.

Originally posted here:
Gene Detectives Find New Tool to Contain Deadly Bacteria

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