CDC spells out ways to stop spread of “nightmare bacteria”

It's not often that researchers approach Centers for Disease Control and Prevention Director Tom Frieden, MD, MPH, with a serious problem and ask him to sound an alarm.

But that's what happened when scientists discovered that a family of bacteria is becoming increasingly resistant to a powerful class of antibiotics, which often are used as a last resort when other drugs don't work.

The proportion of Enterobacteriaceae that were carbapenem-resistant (CRE) increased from 1.2% in 2001 to 4.2% in 2011, the CDC said. Cases of the bacteria have been reported by health care facilities in 42 states. The findings were published online March 5 in the CDC's Morbidity and Mortality Weekly Report.

If action isn't taken now to halt the spread of the bacteria, CRE eventually could begin appearing in healthy people in the community, the CDC said.

“CRE are nightmare bacteria,” Dr. Frieden said. “Doctors, hospital leaders and public health must work together now to … stop these infections from spreading.”

The CDC is urging the health community to focus on detecting patients with CRE so they can receive appropriate care and preventing people from developing the bacteria.

To help identify CRE, the CDC encourages physicians to request that their laboratories issue an immediate alert when they identify a patient with the bacteria. Doctors also should inquire about CRE when receiving patients who are transferred to their facility, the CDC said.

To protect patients from developing infections from CRE, individuals with CRE should be grouped together, and health staff need to wash their hands thoroughly before and after providing care to patients, the CDC said. It's also important to remove medical devices, such as catheters, as soon as possible, because they increase the risk of infection by allowing new bacteria to get deep into a patient's body.

The CDC encourages medical facilities and nursing homes to have specific rooms, equipment and staff for patients with the bacteria. To successfully stop the spread of CRE, health care facilities must work together with local public health departments, which can monitor the bacteria's presence throughout the region, said Arjun Srinivasan, MD. He is the CDC's associate director for Healthcare Associated Infection Prevention Programs in the Division of Healthcare Quality Promotion.

This is “not something that one hospital or one long-term, acute-care hospital can do on its own,” Dr. Srinivasan said.

The CDC encourages states to implement mandatory CRE monitoring. The agency also is pushing for the development of new antibiotics and more research on effective ways to prevent CRE infection and more quickly identify it.

Risk of CRE infection is highest among patients who are getting complex or long-term medical care, including people in nursing homes, the CDC said. Beyond being resistant to nearly all antibiotics, CRE can spread resistance to other bacteria, such as Escherichia coli, and has high mortality rates, the CDC said. Invasive CRE infections, such as those in the bloodstream, are associated with mortality rates exceeding 40%.

Overdone prescriptions a factor

Proper antibiotic prescribing is a key factor in preventing the development of infections from the bacteria, said infectious diseases specialist William Schaffner, MD.

“We ought to think twice and perhaps even three times before we write a prescription for antibiotics,” said Dr. Schaffner, chair of the Dept. of Preventive Medicine at Vanderbilt University School of Medicine in Tennessee.

A third of antibiotics prescribed to patients in hospitals are unnecessary, according to the Society for Healthcare Epidemiology of America.

Hospital-acquired infections kill about 90,000 people in the U.S. each year, according to the CDC. That figure is up from about 13,300 deaths in 1992. More than 70% of the bacteria that cause these infections are resistant to at least one of the antibiotics typically used to treat them.

One of the more common bacterium is methicillin-resistant Staphylococcus aureus, which has spread from the health care setting and increasingly is being diagnosed in otherwise healthy children in the community, medical experts say.

But carbapenem resistance is more complex than MRSA, Dr. Frieden said. For instance, while there are treatment options for MRSA, there are limited or no treatment options for CRE, he said.

To assess the extent of CRE in the U.S. and the proportion of clinical isolates of Enterobacteriaceae that are resistant to carbapenem, researchers examined data from two sources: the CDC's National Healthcare Safety Network and the National Nosocomial Infections Surveillance System. Researchers also examined characteristics of cultures that were positive for CRE by examining data from a surveillance project conducted through the CDC's Emerging Infections Program. Data were collected for that project in Atlanta; Minneapolis-St. Paul, Minn.; and Portland, Ore.

They found that 181 U.S. hospitals reported treating at least one person infected with CRE during the first six months of 2012. Of those infections, 3.9% were reported in short-stay hospitals and 17.8% in long-term, acute-care hospitals.

Most CRE were Klebsiella species, followed by Enterobacter species and E. coli, data show. The bacteria were most frequently reported in the Northeast. The most common source of CRE was urine (89%), followed by blood (10%), the study said.

“Although CRE remain relatively uncommon in most acute-care hospitals in the United States, they have become an increasingly recognized cause of infection during the past decade,” the report said.

Several members of the House Committee on Energy and Commerce sent a letter on March 7 to heads of the panel and its subcommittees. The letter, which was issued in response to the CDC report, requested a hearing on the public health risks of increasingly prevalent and dangerous antibiotic-resistant bacteria.

The committee members recommended hearing from the CDC, the National Institutes of Health and other physicians and researchers to examine the causes of the growing prevalence of antibiotic-resistant bacteria and strategies to control their spread.

“These hearings should be held as quickly as possible to examine the appropriate federal response to this serious threat,” the letter said.