The U.S. Food and Drug Administration said the gel posed "serious health risks" after finding samples of the product were contaminated with two different strains of bacteria.

The gel, called Other-Sonic Generic Ultrasound Transmission Gel, is made by privately held Pharmaceutical Innovations Inc in Newark, New Jersey. It helps improve the transmission of ultrasound waves, high-frequency sound waves that produce images of structures within the body.

The company had no comment.

The FDA said it received a report that 16 people were infected with a type of bacteria called pseudomonas aeruginosa after using the gel for ultrasound during heart valve replacement. This type of bacteria can be fatal if it infects internal organs.

The seized lots of the gel were made between June and December 2011, the FDA said.

The FDA also issued the company a warning letter in July 2011 about manufacturing problems at its facility in Newark, which included not properly documenting that products were sterilized.

(Reporting by Anna Yukhananov)

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