With every new infection and every new death, a few more pieces of the puzzle that is CRE, a highly antibiotic-resistant family of bacteria known as carbapenem-resistant Enterobacteriaceae, are supposed to fall into place. But even though federal health officials have known about CRE since the year 2001, connecting the dots among cases since then has been a struggle for federal agencies and health care providers alike. Four deaths last month – two in California and two in North Carolina -- caused by the bacteria prompted a whirl of questioning about whether public health agencies and departments could have acted more quickly to curb the estimated 9,000 infections and 600 deaths from CRE each year.

Continued piecemeal surveillance and data collection efforts on CRE infections at both the federal and state levels have failed to build -- and are still delaying -- a comprehensive national understanding of how grave a threat CRE poses, health experts suggested. CRE have been found in 48 states, according to the Centers for Disease Control and Protection, yet just 19 officially require certain medical facilities to report cases to public health departments, online registries or other hubs, and only three are close to adding regulations requiring the same. Even more, no federal requirements mandate that states or health care facilities report CRE cases to either state or federal agencies.

“We get no national picture [of CRE infections]. It’s very hard to work with that information,” said Nancy Hailpern, director of regulatory affairs at the Association for Professionals in Infection Control and Epidemiology.

On a national level, hospitals send details and numbers of certain infections to the CDC, but that information is tied to sources of infections, such as medical devices, not the infection-causing pathogen itself (with the exception of two highly resistant bacteria that are not CRE). And of the 19 states that do require intra-state reporting, approaches vary widely from state-to-state.

'States classify CRE differently'

Since Nov. 1, 2013, Illinois has kept a budding registry of extensively drug resistant organisms and detailed guidelines about how to use it. At hospitals, laboratories and some other health care facilities (outpatient clinics and assisted-living centers excluded), the first CRE-positive test in any patient’s stay must be reported by entering cases into the registry’s website. The state also explicitly defines which bacteria and which test results indicate CRE infections. The results have been positive for the state’s  registry, which has "started to build a foundation for statewide CRE control," Melaney Arnold, a spokeswoman for the Illinois Department of Health, said by email. Although it was too soon to determine its impact on the number of infections and deaths, she said health care providers had raised their awareness and knowledge of CRE infections and improved infection control efforts. More significantly, Illinois has begun to use the information compiled in its CRE registry.

In January, Illinois launched a pilot project to automatically alert hospital officials each time a patient with a history of CRE infection checked into a hospital. The alert system proved useful almost immediately: On the first day of the project, a new patient was identified as having a previous CRE infection, Arnold said. "Further development of this automatic alert process at additional hospitals will facilitate ... communication and more rapid infection control response," she added.

Delaware has taken a different approach, at least as shown in requirements made available online. The state includes CRE on its list of notifiable diseases and conditions that must be reported to the Department of Public Health, but does not appear to have a registry. Yet another approach can be found in Montana, which requires both suspected and identified CRE isolates to be sent to the Montana Public Health Laboratory for sample analysis.

“States classify CRE differently,” Laura Evans, legislative affairs representative for the Association for Professionals in Infection Control (APIC), said of these differing approaches. Even the laboratory tests for determining CRE vary among states. “You don’t have an accurate picture of what the extent of the CRE problem is if there isn’t a standard way to define CRE.”

No national requirement to report CRE

Only a few new states seem poised to add their own regulations soon; according to APIC, only Vermont, Kentucky and Indiana are close to adopting CRE reporting requirements. Vermont has been tracking CRE since 2011 but will make regulations official "in the next couple of weeks," according to Dr. Patsy Kelso, a state epidemiologist in the Vermont Department of Health. Kentucky is expected to approve regulations in April, and the Indiana Department of Health is considering adding regulations, Evans said.

“Because there’s no requirement for CRE, the information that the CDC gets is piecemeal,” Hailpern saidl which leaves a dearth of and inconsistency among states reporting CRE infections and don't contribute to a robust national picture of the extent of CRE infections.

The CDC does have some CRE surveillance and testing on its own, said Dr. Jean Patel, deputy director of the CDC’s office of antimicrobial resistance, but it's not comprehensive. Under one program, hospitals in just five states submit possible CRE infections, which the CDC then analyzes. “You can imagine that … we are not catching every single CRE case that happens in the U.S.,” Patel said wryly. Still, she spoke in hopeful terms, adding, “I think tracking of CRE is possible everywhere.”

One reason there are such wide-ranging methods to catch and report CRE cases is because testing for it is challenging, said Patel. CRE actually refers to a whole family of bacteria, meaning that “there are several different genera and species of bacteria,” Patel explained. Although testing has improved since CRE infections first began appearing, it's not perfect. “There are laboratory tests that detect most, if not all, of the types of carbapenem-resistant enterobacteriaceae, and then there are some tests that are very sensitive but they produce a lot of false positive results,” Patel explained. The Food and Drug Administration has yet to approve tests specifically for detecting CRE.

In September 2013, twelve years after it first published a study on CRE infections, the CDC released a report on how antibiotic resistance was a national threat. One year later, the Obama administration unveiled a national strategy revamping an interagency task force on antibiotic resistance that dated back to 1999. At the same time, the president also signed an executive order requiring federal agencies to implement the new national strategy, which included increased surveillance. Obama’s budget for 2016 also set aside $1.2 billion to monitor and curb antibiotic-resistant bacteria and to develop new antibiotics.

Still a work in progress

These new initiatives, however welcome, don’t solve all of the underlying problems in CRE reporting. “We have less information than we should have to enable us to tackle antibiotic resistance,” Allan Coukell, senior director for health programs at the Pew Charitable Trusts, said. He suggested that federal agencies that have existing reporting mechanisms for other infections could add CRE to the list in order to improve national tracking of those infections.

“The main reason reporting started was...just for public health purposes,” said Hailpern of the Association for Professionals in Infection Control. “That’s how you increase patient safety: knowing what the problems are. Otherwise you can’t solve them.” Until the CRE problem is fully understood, solutions that are tailored to address it may just have to wait.