Young children are acquiring with the highly fatal antibiotic-resistant infection known as the “Superbug” at a much higher rate than in the recent past, a new report shows.

The bacterium, known as Carbapenem-resistant Enterobacteriaceae, or CRE, is most often found in inpatient care settings (i.e., hospitals and long term care facilities) and is resistant against many types of antibiotics. As a result, about half of the patients who become infected with CRE die from it, the U.S. Centers for Disease Control and Prevention says.

Although there is a growing amount of information on CRE in adults, little was known about its prevalence in children.

Drawing on a nationwide data base of reports from 300 microbiology laboratories, the study assessed the presence of CRE bacteria in 316,253 cultures obtained from children in the U.S. from 1999 to 2012.

The study found that CRE in children is still relatively uncommon, but that the rate of infection had increased significantly among children of all ages and settings, from zero percent in 1999-2000 to .47 percent in 2011-2012.

The greatest increase, from zero to 4.5 percent, was found in cultures from children between ages one through five cared for in intensive care units. In addition, CRE isolates found in the bloodstream increased from zero to 3.2 percent during the study period. This is important because up to half of those who develop CRE bloodstream infection die from the infection, the CDC said.

The study appears in the journal Emerging Infectious Diseases.