The maker of medical scopes that have been linked to two recent "superbug" outbreaks at California hospitals has issued new cleaning instructions for the devices amid scrutiny from regulators, lawmakers and medical professionals.

Olympus America sent the new guidelines to U.S. hospitals on Thursday, recommending that its customers begin using them as soon as possible. The updated guidelines call for using a smaller cleaning brush and additional flushing steps to remove debris and disinfect the scope's crevices and hinges. Olympus plans to send the new brush to hospital customers by May 8.

The company's scopes were linked to infections of antibiotic-resistant bacteria in 11 patients at two separate Los Angeles hospitals last month, contributing to the deaths of two of those patients. Hospital staff said the infections occurred despite following Olympus' instructions for cleaning the devices, known as duodenoscopes.

The scopes consist of a flexible fiber-optic tube that is threaded down the throat, through the stomach and small intestine to diagnose and treat conditions in the pancreas and bile ducts. The tip of the scope includes moveable parts for instruments to help remove tumors, gallstones and other blockages. But this complex design also makes the instruments difficult to clean. Bodily fluids and other debris can stay in the device's joints and crevices even after cleaning and disinfection.

The FDA said in a statement it is reviewing the new cleaning instructions from Olympus as part of a broader evaluation of the company's device.

The agency previously disclosed that Olympus did not seek federal clearance for the latest version of its duodenoscope, which it began selling in 2010. FDA clearance is required for all substantive updates to medical devices sold in the U.S. The company's Olympus TJF-Q180V duodenoscope is currently under FDA review.

Despite the lack of clearance, the FDA said doctors should not stop using the device because it's not clear that a federal review would have prevented the recent contamination problems reported at hospitals.

Congressman Ted Lieu, D-Calif., said the Olympus update was an important "first step," but pointed out that the FDA has not yet confirmed its effectiveness for disinfecting the scopes.

"Hopefully this will work, but we won't know for some time," Lieu said in an interview with The Associated Press. "But I do commend them for taking action." On Tuesday Lieu sent a letter to Olympus requesting details about its handling of the duodenoscope issue.

Seven lawsuits have been filed against Olympus in Los Angeles County Superior Court on behalf of patients, alleging negligence and fraud by the company.