The largest outbreak of a very specific and very dangerous bacteria in the U.S. has been linked to procedures performed at a north suburban hospital last year.
The Centers for Disease Control and Prevention has discovered 44 cases of a strain of bacteria called carbapenem-resistant enterobacteriaceae, or CRE, in northeast Illinois, including 38 confirmed cases involving patients at Advocate Lutheran General Hospital in Park Ridge who underwent an endoscopic procedure of the pancreas or bile ducts between January and September 2013.
There have only been 96 cases reported in the U.S. since the bacteria was first reported in 2009. The outbreak is a form of CRE called NDM-1, or an enzyme that makes bacteria resistant to antibiotics. And prior to last year, the largest outbreak the CDC had seen was 10 cases found in Denver.
“A large number of patients have been identified, a large number of transmissions — total of 44 — and 39 of those were found in the Chicago area. It’s the largest outbreak that we’ve seen in the U.S. of this bacteria ever,” said Alex Kallen, an infectious diseases doctor who served as the supervisor of the CDC investigation.
The bacteria is highly resistant and is mainly found in people in healthcare settings, like nursing homes. The most common infection the bacteria causes is a urinary tract infection, but if that infection goes to the bloodstream, the patient has a 40 to 50 percent chance of dying.
The bacteria is in a family of more than 70 bacteria including E. coli that normally live in the digestive system, according to the Illinois Department of Public Health. But some of those bacteria have become resistant to antibiotics, including a group of antibiotics known as carbapenems, often referred to as “last-resort” antibiotics.
Kallen said most of the 243 patients screened at Advocate Lutheran General found to have had exposure to the bacteria were “colonized,” not infected, meaning the bacteria lived in their digestive track but did not cause a disease.
According to the hospital, 28 patients screened positive for the organism but didn’t have an infection. Ten others showed signs and symptoms. They declined to provide further information on the condition of the patients, but said a small percentage of patients were treated for the infection with antibiotics.
A history of undergoing the endoscopic retrograde cholangiopancreatography (ERCP) was strongly associated with the bacteria, according to the CDC’s Morbidity and Mortality Weekly Report issued Jan. 3. Even after manual cleaning and “high-level disinfection,” cultures from the device recovered E. coli and other bacteria.
The study however finds there were no flaws in protocol.
“The design of the ERCP endoscopes might pose a particular challenge for cleaning and disinfection,” the CDC report said.
The procedure is used to view the stomach and intestines and is used to diagnose conditions related to the bile duct, pancreatic cancer and gallstones. It is not the same scope procedure used for common stomach ulcers, Kallen said.
The hospital reached out to all who underwent the procedure. Each received a registered letter explaining the situation and asked that they return to the hospital for a screening test to confirm whether they were exposed to the bacteria, according to Leo Kelly, Vice President of Medical Management at Advocate Lutheran General Hospital.
Of that number, 109 have been tested, while additional screenings are scheduled.
“We encourage those who may not have yet come in for the screening to do so,” Kelly said in an email.
The hospital first discovered the problem six months ago when seven patients returned to the hospital with a CRE infection. An investigation was conducted which showed the link between the procedure and the CRE infections, the hospital said.
Although the investigation is ongoing, the hospital has changed the way it sterilizes the scopes — even though the CDC and the Illinois Department of Public Health did not find any problem with the way they were disinfected.
“To ensure no other patients are at risk, we have moved to gas sterilization for these particular scopes, which exceeds the manufacturer’s recommended cleaning and disinfectant guidelines,” Kelly said. Gas sterilization is the cleaning method used in operating rooms.
Whether the bacteria spread from the scope is still unclear, and the CDC, the IDPH, the Cook County Dept. of Public Health and the Federal Drug Administration are investigating.