Amesh A. Adalja, MD, FACP, FACEP, FIDSA, April 29, 2016
Several Midwestern states are in the midst of a mysterious outbreak of bacteremia (and other infections) caused by Elizabethkingia—an environmentally ubiquitous bacterium that is, in rare cases, capable of causing infections in compromised hosts.
In late 2015, Wisconsin’s Department of Health was notified of clusters of infections with Elizabethkingia anopheles. The identification of this cluster of infections triggered epidemic alerts to neighboring states, ultimately resulting in the identification of similar cases in Illinois and Michigan. Total cases now number more than 60 with at least 20 deaths.
Investigation of the source of this outbreak is ongoing, and no common link has been found to date. However, the majority of cases exhibit bacteremia and are above 65 years of age with major underlying health conditions.
The most well known of the Elizabethkingia genus is E. meningosepticum, an established cause of neonatal meningitis linked to contamination of saline eye flushes, sinks, and ventilator tubing. In rare circumstances, immunocompromised adults can be infected, usually via the respiratory tract through contaminated ventilator tubing. Bloodstream infections, arthritis, and keratitis have also been noted.
Often Elizabethkingia can be resistant to multiple antimicrobial agents with chromosomally encoded metallo-β-lactamases rendering them intrinsically resistant to carbapenems. In the current outbreak, fluoroquinolones, rifampin, and trimethoprim-sulfamethaxazole are likely to be effective based on antimicrobial susceptibility testing. Combination therapy is advised, and contact precautions are being used for hospitalized patients.
This outbreak illustrates how, in the right circumstances, a rare pathogen can cause a deadly multistate chain of infections. Astute clinicians and microbiologists who detected aberrancy in the expected rate of Elizabethkingia infections in Wisconsin were an essential component in bringing this outbreak to light and identifying its full extent. The unfolding of this outbreak highlights the absolute importance of having situational awareness of outbreaks in a community, a state, and a region. The most pressing need to control this outbreak is to determine the source of exposure and, once identified, to attempt to minimize this risk in the future.
Elizabethkingia. Wisconsin Department of Health Services website. Updated April 27, 2016. https://www.dhs.wisconsin.gov/disease/elizabethkingia.htm. Accessed April 27, 2016.
Elizabethkingia. Centers for Disease Control and Prevention website. Updated April 20, 2016. http://www.cdc.gov/elizabethkingia/index.html. Accessed April 27, 2016.