The largest known outbreak of the bacterium, Elizabethkingia anophelis, has grown by one in Wisconsin reported an additional confirmed case this week, bringing the total confirmed cases to 61 since last Nov. 1.

Single colonies of Elizabethkingia anophelis growing on blood agar/CDC
Single colonies of Elizabethkingia anophelis growing on blood agar/CDC

In addition, the Wisconsin Department of Health Services (DHS) have reported four “possible” cases.

Counties with confirmed cases include Columbia, Dane, Dodge, Fond du Lac, Jefferson, Milwaukee, Ozaukee, Racine, Sheboygan, Washington, Waukesha and Winnebago.

There have been 18 deaths among individuals with confirmed Elizabethkingia anophelis infections and an additional 1 death among possible cases for a total of 19 deaths. It has not been determined if these deaths were caused by the infection or other serious pre-existing health problems. Counties where these deaths occurred are: Columbia, Dodge, Fond du lac, Milwaukee, Ozaukee, Racine, Sheboygan, Washington and Waukesha.

The majority of the infections identified to date have been bloodstream infections, but some patients have had Elizabethkingia isolated from other sites, such as their respiratory systems or joints.

The majority of the patients who have had Elizabethkingia infections as part of this outbreak are over the age of 65 years, and all have had serious underlying health conditions. It has not been determined whether the deaths associated with this outbreak were caused by the bacterial infection, the patients’ underlying health conditions, or both.

According to the Centers for Disease Control and Prevention (CDC), Elizabethkingia is a genus of bacteria commonly found in the environment worldwide and has been detected in soil, river water and reservoirs. However, it rarely makes people sick.

Cases are diagnosed through culture of body fluids, most often blood testing. Elizabethkingia has mostly caused meningitis in newborn babies and meningitis or bloodstream and respiratory infections in people with weakened immune systems.

About 5-10 cases per state per year are reported in the United States, with a few small, localized outbreaks reported in both the United States and other countries, usually in healthcare settings.

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