(CNN) Three people died and 45 people developed infections from contaminated endoscopes, the US Food and Drug Administration said Friday.

The reports of contamination are with a side-viewing duodenoscope used for a medical procedure called endoscopic retrograde cholangiopancreatography or ERCP. "These flexible lighted scopes are vital for minimally invasive procedures to diagnose and treat conditions of the pancreas and bile duct," said Dr. Jeff Shuren, director of the FDA's Center for Devices and Radiological Health.

The reusable scopes, which are made by three manufacturers -- Fujifilm Medical Systems USA Inc., Olympus Medical Systems Corporation and Pentax of America -- are known to be difficult to decontaminate. They have been linked to deadly outbreaks of the superbug carbapenem-resistant Enterobacteriaceae, or CRE. The contamination issues result from damaged scopes and improper decontamination.

In 2015, the FDA required the manufacturers to conduct post-market surveillance studies to fix the problem.

The agency said Friday, "The preliminary results as of March 2019 indicate higher than expected levels of contamination."

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