The Centers for Disease Control and Prevention reported on Tuesday that two more Pseudomonas aeruginosa-related deaths have been added to the outbreak of highly drug-resistant bacteria linked to recalled eye drops.

According to the CDC’s most recent update, out of 68 patients with the bacteria identified across 16 states, eight people have lost their vision, and four have had their eyeballs removed. A man from Washington state had previously been reported as having died.

As health authorities scrambled to look into the outbreak suspected to be connected to opened eye drops purchased online, in stores, and through ophthalmologist offices, a total of three eye products — all imported from Indian company Global Pharma Healthcare Private Limited — were recalled.

In recent weeks, two eye products made by different manufacturers have also been recalled due to unrelated contamination concerns.

The outbreak’s Pseudomonas aeruginosa strain is extremely uncommon and has never been observed in the United States before. Since it has become resistant to a dozen different antibiotics, treating it is particularly difficult for doctors.

The CDC reports that researchers at the University of California, San Diego, have found a bacteriophage that may be able to treat the highly drug-resistant bacteria, which coincides with news of the outbreak’s rising death toll.

The university’s Center for Innovative Phage Applications and Therapeutics has previously praised the “phage” treatments it created to treat patients with infections brought on by bacteria with drug resistance.

These treatments work by deploying viruses that target bacteria to combat infections that conventional antibiotics cannot eradicate.

The number of patients who have been treated with the bacteriophage discovered for the current outbreak, if any, is unknown. When contacted for comment, the center did not respond right away.