A Los Angeles-area hospital said Wednesday that some of its patients contracted an antibiotic-resistant "superbug" that has been linked to a type of medical scope and infected dozens of people around the country.

Huntington Memorial Hospital said in a statement that it notified public health authorities after several patients who had procedures using Olympus Corp. duodenoscopes were found to have the resistant pseudomonas bacteria.

The hospital said it has quarantined the scopes while it investigates whether they may be linked to the infections.

The statement made no mention of the total number of infected patients or their conditions.

However, the Los Angeles Times said the problem was discovered in June and three patient infections have been reported to health officials.

Drug-resistant bacterial infections around the country have been linked to contamination of the reusable scopes, which are used for a procedure known as endoscopic retrograde cholangiopancreatography. The fiber-optic scopes are placed down a patient's throat and used to diagnose and treat gallstones, blockages and cancers of the digestive tract.

"The patients who experienced the bacterial growth were very ill before they underwent the scope procedure, and the risk of the procedure was explained to each patient and family," Huntington Memorial's statement said.

A dozen infections were reported earlier this year at Cedars-Sinai and UCLA's Ronald Reagan medical centers in Los Angeles. Three patients died.

The hospitals said the infections occurred even though the devices had been cleaned to the manufacturer's standards. They have since implemented more stringent disinfection procedures.

Olympus is the market leader for duodenoscopes in the U.S., accounting for about 85 percent of sales, according to the U.S. Food and Drug Administration.

On Monday, the FDA posted a warning letter online that said Olympus waited three years to alert regulators to a cluster of 16 infections in patients who underwent procedures using the scope in 2012.

Additionally, FDA inspectors found that the company has no standard procedure for promptly reporting serious problems with its devices, a requirement for medical device companies.

The company said it was reviewing the FDA's warning.

The FDA also posted warning letters Monday to two other scope manufacturers citing problems with the testing, design, reporting and quality control of their devices.