SAN DIEGO (AP) – State health officials are investigating a mishap at Scripps Memorial Hospital that may have exposed nearly 300 obese patients who underwent stomach-reduction surgery to hepatitis or HIV.

Scripps officials said the patients had a “very low” risk of infection because a registered nurse had knowingly violated operating room procedures. The female nurse, whose name was not released, failed to fully clean several gastroscopes, which are used to retrieve other surgical instruments from the stomach.

The nurse worked at the hospital from September 2004 until last month when she resigned after hospital officials confronted her about the issue.

“This employee was aware of the procedures and chose not to follow them, which is something we do not tolerate,” said Scripps spokesperson Don Stanziano

The hospital has contacted 250 of the 299 patients at risk, many of whom reside outside Southern California.

Lea Brooks, a spokesperson for Department of Health Services, said investigators would examine what happened and what Scripps is doing to ensure problems are fixed. The hospital will have to prepare a plan of corrective action, Brooks said.

The state Department of Consumer Affairs will decide whether to initiate disciplinary action against the nurse.

Stanziano said the chances of infection were remote because the gastroscopes had undergone preliminary washes and rinses, although they were not sterilized with chemicals.

“We have been assured by both local and national experts the risk of infection is very low,” said Stanziano. “HIV is a fragile virus so it is unlikely to have survived the process.”

Brooks added that hepatitis B and C viruses pose a slightly higher risk of transmission, but the risk remains low.

Patients undergoing stomach-reduction or bariatric surgery are considered morbidly obese – more than 100 pounds overweight. The procedure is also known as stomach stapling.