Microbiology and Genome Experts Quell Deadly Bacteria Outbreak

Collaboration helped control multi-drug resistant bacterial infection at research hospital

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WEDNESDAY, Aug. 22 (HealthDay News) -- A deadly outbreak of antibiotic-resistant bacteria at a U.S. research hospital lasted six months and was finally brought under control through the combined efforts of genomics and microbiology experts, government researchers report.

The outbreak began when a 43-year-old New York City patient carrying a multi-drug resistant strain of Klebsiella pneumoniae introduced the dangerous bacteria into the 243-bed U.S. National Institutes of Health's Clinical Center in Bethesda, Md., in June 2011. The microbe is a common cause of hospital-borne infections.

Even with enhanced infection-control procedures, including patient isolation, the bacteria began to spread to other patients in the facility at the rate of one a week. The bacteria eventually affected 17 patients. Ten of these patients died; six from infection and four from underlying diseases while infected.

Clinical Center staff worked with investigators at the U.S. National Human Genome Research Institute (NHGRI) to use genome sequencing to learn how the microbe spread. That collaboration helped bring the outbreak under control by the end of the year. Since then, there have been no new cases associated with the outbreak.

"Infectious outbreaks happen in every hospital in the world, afflicting millions of patients each year in the United States alone," NHGRI director Dr. Eric Green, said in an NIH/NHGRI news release.

"By marshaling the ability to sequence bacterial genomes in real time to accurately trace the bacteria as it spread among our Clinical Center patients, our researchers successfully elucidated what happened, which in turn has taught us some important lessons," he explained. "This study gives us a glimpse of how genomic technologies will alter our approach to microbial epidemics in the future."

A case history of the outbreak was published online Aug. 22 in the journal Science Translational Medicine.

"Genome sequencing and analysis is our best hope for anticipating and outpacing the pathogenic evolution of infectious agents," Julie Segre, an NHGRI senior investigator involved in the outbreak, said in the news release. "Though our practice of genomics did not change the way patients were treated in this outbreak, it did change the way the hospital practiced infection control."

About 1.7 million hospital-associated infections, and 99,000 related deaths, occur each year in the United States, according to the U.S. Centers for Disease Control and Prevention. Multi-drug resistant K. pneumoniae is among the more dangerous infections because there are few effective treatments and the death rate can be as high as 50 percent, the researchers pointed out in the news release.

They also noted that multi-drug resistant K. pneumoniae -- which is an increasing problem in health-care facilities -- is most dangerous for patients with immune systems weakened by medical procedures or by conditions such as advanced age and illness.

In another case, which was described in a report in the June 21 issue of the Morbidity and Mortality Weekly Report, published by the CDC, swift treatment and infection control measures prevented the spread of rare but deadly New Delhi metallo-beta-lactamase-producing K. pneumoniae that was found in two patients in a Rhode Island hospital in 2011.

Commenting on that report, lead researcher Dr. Leonard Mermel, medical director of the department of epidemiology and infection control at Rhode Island Hospital in Providence, said: "These people had the bacteria in their body, but fortunately it was not causing an infection anywhere."

More information

The U.S. Centers for Disease Control and Prevention has more about health care-associated infections.

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