A fourth person has died from an outbreaking linked to a drug-resistant bacteria tied to recalled eye drops, U.S. health officials said.

According to the Centers for Disease Control and Prevention, as of May 15, 81 patients from 18 states have become infected with Pseudomonas aeruginosa, a bacteria strain that has never been reported in the U.S. prior to this outbreak. Cases have been reported in California, Colorado, Connecticut, Delaware, Florida, Illinois, North Carolina, New Jersey, New Mexico, Nevada, New York, Ohio, Pennsylvania, South Dakota, Texas, Utah, Washington, and Wisconsin.

There have been four deaths linked to the infections, along with 14 patients with vision loss, and four cases involving the surgical removal of an eyeball. In March, the CDC reported three deaths and eight cases of vision loss.

Three eye products, all imported from Indian make Global Pharma Healthcare Private Ltd. – EzriCare Artificial Tears, Delsam Pharma’s Artificial Tears and Delsam Pharma’s Artificial Eye Ointment – have been recalled.

Seven infected patients had specimens collected after the recall’s announcement, the CDC said. Of those, most either resided in long-term care facilities with other known cases or reported use of a recalled brand of artificial tears.

“These cases were confirmed after the recall date due to the time it takes for testing to confirm the outbreak strain and because of retrospective reporting of infections,” the CDC said in an update.

Most of the patients who were infected with the bacteria reported using artificial tears with EzriCare, a preservative-free, over-the-counter product packaged in multidose bottles.

People are advised to stop using the products and seek immediate medical attention if they have symptoms of an eye infection:

Symptoms of an eye infection include:

• Yellow, green, or clear discharge from the eye
• Eye pain or discomfort
• Redness of the eye or eyelid
• Feeling of something in your eye (foreign body sensation)
• Increased sensitivity to light
• Blurry vision