LOS ANGELES — A "superbug" outbreak suspected in the deaths of two patients at a Los Angeles hospital has raised questions about the adequacy of the procedures for disinfecting a medical instrument used on more than a half-million people in the U.S. every year.
At least seven people — two of whom died — have been infected by a potentially lethal, antibiotic-resistant strain of bacteria after undergoing endoscopic procedures at Ronald Reagan UCLA Medical Center between October and January, and more than 170 other patients may have been exposed as well, UCLA said.
UCLA said Wednesday that the infections may have been transmitted through at least two contaminated endoscopes that were used to diagnose and treat pancreatic and bile-duct problems.
An endoscope — or more specifically in this case, a duodenoscope — is a thin, flexible fiber-optic tube that is inserted down the throat to enable a doctor to examine an organ. The device typically has a light and a miniature camera.
"We notified all patients who had this type of procedure, and we were using seven different scopes. Only two of them were found to be infected. In an abundance of caution, we notified everybody," UCLA spokeswoman Dale Tate said.
The two medical devices carried the bacteria even though they had been sterilized according to the manufacturer's specifications, UCLA said.
"We removed the infected instruments, and we have heightened the sterilization process," Tate said.
On Thursday, the U.S. Food and Drug Administration issued an advisory warning doctors that even when a manufacturer's cleaning instructions are followed, infectious germs may linger in the devices. Their complex design and tiny parts make complete disinfection extremely difficult, the advisory said.
More than 500,000 patients undergo procedures using duodenoscopes in the U.S. every year, according to the FDA.
The germ is known as Carbapenem-resistant Enterobacteriaceae, or CRE, and similar outbreaks have been reported around the nation. They are difficult to treat because some varieties are resistant to most known antibiotics.
By one estimate, CRE can contribute to death in up to half of seriously infected patients, according to the U.S. Centers for Disease Control and Prevention.
CRE can cause infections of the bladder or lungs. Symptoms can include coughing, fever and chills.
The bacteria may have been a "contributing factor" in the deaths of two UCLA patients, the university said in a statement. Those who may have been exposed are being sent free home-testing kits that the university will analyze.
National figures on the bacteria are not kept, but 47 states have seen cases, the CDC said.
One outbreak occurred in Illinois in 2013. Dozens of patients were exposed to CRE, with some cases apparently linked to a tainted endoscope used at a hospital.
A Seattle hospital, Virginia Mason Medical Center, reported in January that CRE linked to an endoscope sickened at least 35 patients, and 11 died, though it was unclear whether the infection played a role in those deaths.
AP Medical Writer Mike Stobbe in New York contributed to this report.