Lab Matters Summer 2023 | Page 24


Blurred Vision , Clear Danger : Multistate Outbreak Response Launched over Contaminated Artificial Tears

By Nikki Marchan , senior specialist , Antimicrobial Resistance of the VIM-GES-CRPA infection . Records and interviews identified a common product as EzriCare Artificial Tears , an over-the-counter preservative-free product manufactured by Global Pharma in India , as the only common artificial tears product identified across the four healthcare facility clusters .
The investigation started in Los Angeles County , California , where a doctor called one case the worst eye infection he ’ d ever seen . 1 Soon , there would be more .
The US Centers for Disease Control and Prevention ( CDC ), in collaboration with state and local health departments and the US Food and Drug Administration ( FDA ), is actively engaged in the surveillance and identification of cases in a multi-state outbreak investigation to identify patients with an extensively drug resistant bacterial infection . The infections are being caused by a strain of carbapenem-resistant Pseudomonas aeruginosa ( CRPA ) that produces the Verona integron-encoded metallo-βlactamase ( VIM ) and the Guiana-Extended Spectrum-β-Lactamase ( GES ). Sequenced isolates were identified as P . aeruginosa sequence type ( ST ) 1203 harboring the
bla VIM-80 and bla GES-9 genes , a combination never observed in the United States . With less than one-third of US hospitals able to test for CRPA , public health laboratories are critical partners in identifying and responding to cases . As of May 15 , 2023 , 81 cases of the strain have been identified in 18 states . These cases came from specimens collected between May 2022 and April 2023 from both outpatient and inpatient healthcare settings .
A Difficult Proposition
The investigation to identify the source of the outbreak was complicated by differences between cases , the fact that the healthcare facility clusters were in different geographical locations , and patients were identified over a span of months . Isolates were obtained from a variety of specimen types , such as sputum , eye wash , urine , blood and rectal swabs . Patient ages ranged from less than one year to over 100 , and the observed symptoms included keratitis , respiratory infection , urinary tract infection and sepsis — with severe cases leading to permanent vision loss , hospitalization and death .
One identified cluster was in an ophthalmologist ’ s office , which allowed for the hypothesis that a single eye care product was the cause . Though the other identified infections were found in the lungs of patients in long-term care facilities , the anatomical structure of tear ducts allows for drainage into nasal cavities . This would allow for an infection to spread to the lungs and other parts of the body .
Epidemiological investigation found that most patients — including those with ocular infections — had previously used artificial tears prior to the identification
Laboratory testing confirmed the presence of VIM-GES-CRPA in opened EzriCare Artificial Tears bottles from multiple lots . Testing of unopened bottles of EzriCare Artificial Tears is ongoing to determine whether contamination occurred during manufacturing .
The Importance of Collaboration
Isolates associated with this outbreak are extensively drug resistant and research is ongoing to determine potential treatment options . The AR Lab Network offers carbapenem resistance mechanism testing and expanded antimicrobial susceptibility testing to aid in clinical decision making and can be utilized as a resource for clinicians looking to inform drug treatment options . Additionally , a bacteriophage with activity against the outbreak strain has been identified and is available as a potential treatment option through the University of California at San Diego ’ s Center for Innovative Phage Applications and Therapeutics ( IPATH ).
The investigation is still ongoing to identify current and past cases . However , the work during this complex response highlights the impressive investigation skills and coordinated efforts at work when clinical , public health laboratory and epidemiology partners engage in collaboration . The work done by each party — laboratories to detect , epidemiologists to respond and infection control experts to prevent further spread — likely kept this outbreak from becoming much larger . g
References :
1 . How US officials cracked mystery of eyedrops that blinded people across the country . PBS New Hour ( website ). Available from https :// www . pbs . org / newshour / health / how-u-s-officials-cracked-mystery-of-eyedrops-that-blinded-people-across-country
22 LAB MATTERS Summer 2023
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