Another person has died in an outbreak of highly drug-resistant bacteria linked to contaminated eye drops, the Centers for Disease Control and Prevention reported in an update Thursday.
The outbreak now has 81 cases in 18 states. In addition to the four deaths, health officials have collected reports of 14 people with vision loss and another four people who had their eyeballs surgically removed (enucleated) due to infection.
The bacteria behind the outbreak is a strain of Pseudomonas aeruginosa called VIM-GES-CRPA. This cumbersome acronym stands for a carbapenem-resistant P. aeruginosa (CRPA) with Verona integron-mediated metallo-β-lactamase (VIM) and Guiana extended-spectrum β-lactamase (GES). It is a highly resistant strain of bacteria that had never been seen in the US before this outbreak.
US health officials have traced the origin of the bacteria to contaminated eye drops, with EzriCare artificial tears being the most common product used by people infected during the outbreak. The Food and Drug Administration reported a recall of these drops in February after the CDC issued a health alert about 55 cases and the link to the eye drops. The manufacturer of EzriCare eye drops, India-based Global Pharma, also recalled two other products it makes: Delsam Pharma’s Artificial Tears and Delsam Pharma’s Artificial Ointment. The CDC and FDA advise people to stop using these products immediately if they haven’t already.
Before the recalls, the eye drops were available nationwide and sold through Amazon, Walmart, eBay, and other retailers. Clinical samples indicate contamination periods from at least May 2022 to April 2023, although the CDC has advised healthcare professionals to report suspected clinical samples dating back to January 2022.
This week’s outbreak update includes 13 new cases since the last outbreak update in March, six of which had samples taken prior to the recall and have now been confirmed and added to the tally. Of the seven other newly added cases, most either lived in long-term care facilities with other known cases or reported continuing to use one of the recalled artificial tears, the CDC reported.
Threat to public health
CDC officials previously told Ars that the outbreak strain is of particular concern because it can spread quietly from person to person and share drug resistance genes with other pathogens.
“To date, extremely resistant Pseudomonas with genes that rapidly spread resistance, such as VIM and GES, are rare in this country,” Marissa Grossman, a CDC epidemic intelligence officer, told Ars. “The widespread introduction of the outbreak strain … threatens to undermine efforts to prevent the emergence of these highly resistant organisms.”
Based on bacterial isolates collected during the outbreak, the strain of P.aeruginosa is resistant to antibiotics: cefepime, ceftazidime, piperacillin-tazobactam, aztreonam, carbapenems, ceftazidime-avibactam and ceftolozane-tazobactam, fluoroquinolones, polymyxins, amikacin, gentamicin and tobramycin, the CDC reported. Based on three isolates that have undergone antimicrobial susceptibility testing, the strain still appears to be susceptible to the drug cefiderocol. But the CDC advised doctors to work with specialists to determine treatment plans for the highly resistant pathogen.
The agency also highlighted that researchers from the University of California San Diego’s Center for Innovative Phage Applications and Therapeutics (IPATH) and the Yale Center for Phage Biology and Therapy have identified bacteriophage with activity against the outbreak strain. Bacteriophage (or simply phage) are viruses that selectively infect and destroy bacteria, and researchers have spent decades exploring ways to use them to treat bacterial infections. Interest in the therapy has increased as pathogenic bacteria have become increasingly resistant to our largely stagnant pool of antibiotics.
As doctors and researchers work to treat the persistent infections, some patients have already filed lawsuits against EzriCare, Global Pharma and retailers. The FDA posted an inspection report of Global Parma’s facility, which found a slew of manufacturing violations, slime on equipment, and a lack of measures to ensure sterility.
