By Stan Deresinski, MD, FACP, FIDSA
Clinical Professor of Medicine, Stanford University
SYNOPSIS: An outbreak of extensively drug-resistant Pseudomonas aeruginosa infection has been traced to use of contaminated artificial tears.
SOURCE: Centers for Disease Control and Prevention. Outbreak of extensively drug-resistant Pseudomonas aeruginosa associated with artificial tears. Updated Feb. 3, 2023. https://www.cdc.gov/hai/outbreaks/CRPA-artificial-tears.html
The Centers for Disease Control and Prevention (CDC), working with state and local health departments, identified an unusual outbreak of extensively drug-resistant Pseudomonas aeruginosa infections that were associated with the use of contaminated artificial tears. A total of 55 affected patients in 12 states were identified, with cultures having been obtained from May 2022 to January 2023. The organism was recovered from sputum or bronchial lavage specimens in 13 patients, from the cornea in 11 patients, from urine in seven patients, from blood in two patients, and from other nonsterile sources in four patients. It also was recovered from rectal swabs obtained for surveillance purposes in 25 patients. As of Jan. 31, one patient had died and five had experienced vision loss. Of the 55 patients, 35 were linked to one of four healthcare facility case clusters.
It was determined that most of the patients reported that they had used one or more of 10 different brands of artificial tears. One brand, EzriCare Artificial Tears, was the most frequently used and was the only product common to all four clusters. EzriCare, which is preservative-free, is sold over the counter in multidose vials. Testing identified the outbreak strain Verona integron-mediated metallo-β-lactamase and Guiana extended-spectrum-β-lactamase carbapenem-resistant Pseudomonas aeruginosa (VIM-GES-CRPA) in open bottles from multiple lots of EzriCare that were collected in two states from patients with and without eye infections. Furthermore, VIM-GES-CRPA recovered from these bottles genetically matched the outbreak strain. The CDC recommends that the use of EzriCare immediately be stopped while further investigations continue.
COMMENTARY
The strain of P. aeruginosa causing these infections produces both VIM (Verona integron-mediated metallo-β-lactamase) and GES (the Guiana-extended-spectrum-β-lactamase), hence its designation as VIM-GES-CRPA. They are all of sequence type 1203 and carry an unusual combination of VIM and GES variants. Testing in public health laboratories identified non-susceptibility to cefepime, ceftazidime, piperacillin-tazobactam, aztreonam, carbapenems, ceftazidime-avibactam, ceftolozane-tazobactam, fluoroquinolones, polymyxins, amikacin, gentamicin, and tobramycin. However, all three isolates tested against cefiderocol were susceptible to this siderophore cephalosporin. No data in the activity of the combination of ceftazidime/avibactam and aztreonam were reported.
The CDC recommends that CRPA isolated from an ocular source or VIM-CRPA from any source (blaGES is not included in commercially available carbapenemase gene testing systems) be reported to the public health department and that the isolates be saved for possible further testing and submission to the CDC Antimicrobial Resistance Laboratory Network. If VIM-CRPA is recovered from an inpatient, healthcare contacts should be screened for colonization and laboratory look-back should be performed, along with prospective surveillance with submission of isolates to a public health laboratory. Infected or colonized patients should be managed with contact precautions. The limited in vitro susceptibility test data suggest that cefiderocol may be a reasonable choice for systemic therapy of infection with this organism.
