Incidence of KPC-producing bacteria is rising in Chicago

Rush University Medical CenterOct 25 2010

In a survey of Chicago-area healthcare facilities, researchers at Rush University Medical Center and the Cook County Department of Public Health have found that the incidence of KPC-producing bacteria is rising. These bugs cause infections with high mortality rates and are resistant to the most commonly used antibiotics.

KPC, or Klebsiella pneumoniae carbapenemase, is a type of antibiotic resistance most often found in variants of Klebsiella pneumoniae, common bacteria that naturally live on the skin and in the mouth and intestines and can cause pneumonia and urinary tract infections. The bacteria were first identified in the U.S. on the East Coast in 1999 and have been gradually spreading across the country. The first report of the bacteria in Chicago was in 2007.

The survey found that between 2009 and 2010, the number of healthcare facilities in Chicago that reported infections with the bacteria increased by 30 percent, and the number of patients who tested positive for the bacteria nearly tripled.

Specifically, in 2009, 26 of 54 health facilities reported identification of KPC-producing bacteria. A year later, that number increased to 37 of 57 facilities. The mean number of patients who tested positive for the bacteria at each facility increased from 3.8 to 10.2.

The results of the survey are being presented Friday, October 22, at the 48th annual meeting of the Infectious Diseases Society of America in Vancouver.

"KPC-producing bacteria are a common type of bacterium that has evolved into a dangerous source of infection and a major challenge for infection control," said Dr. Mary Hayden, director of clinical microbiology and associate professor of infectious diseases and pathology at Rush University Medical Center. "Infections due to these bacteria are difficult to treat because most strains are resistant to the majority of our usual antibiotics. Some strains are resistant to all drugs."

Hayden and her colleagues found that 75 percent or more of the patients who tested positive for the bacterium had been in a long-term care facility, such as a nursing home.

"Since antibiotics are virtually ineffective against these bacteria, prevention is key," Hayden said.

One important measure, she said, is coordination between long-term care facilities and acute-care hospitals, since patients who are infected with KPC-colonizing bacteria are often transferred between facilities for treatment. Contact isolation is crucial to control spread of the bacteria.

According to Hayden, infection with KPC-positive bacteria is associated with high mortality. In one study, she said, researchers had found that patients infected with these bacteria were three times as likely to die as were patients infected with similar, but KPC-negative bacteria.

KPC-producing bacteria can spread rapidly throughout a geographic region. Israel had a major outbreak of the bacteria only a few years after the first case was identified.