The very unusual Elizabethkingia anophelis outbreak reported in a dozen Wisconsin counties since Nov. 2015 has infected 48 people, most elderly and all with an underlying health issue, resulting in 15 deaths, although it has not been determined if the cause is the bacterial infection, or the patients’ other serious health conditions, or both.

Elizabethkingia anophelis growing on a blood agar plate. Image/CDC's Special Bacteriology Reference Lab
Elizabethkingia anophelis growing on a blood agar plate.
Image/CDC’s Special Bacteriology Reference Lab

According to Dr. Nasia Safdar, director of infection control at UW Hospital and Clinics and faculty at the University of Wisconsin School of Medicine and Public Health, “Most of the time we’ll see very sporadic cases, maybe one or two a year if that. And most of them are in the context of some association of the health care facility.”

Elizabethkingia are opportunistic pathogens preferentially causing illness among immune compromised individuals or patients with underlying medical conditions (malignancy, diabetes mellitus, chronic renal disease or end-stage renal disease on dialysis, alcohol dependence, alcoholic cirrhosis, immune-compromising conditions or immunosuppressive treatment), and are associated with high mortality.

Wisconsin health officials say that all Elizabethkingia strains identified as E. meningoseptica isolated at local clinical labs are tested at the Wisconsin state lab and if the result is determined to be indistinguishable, the strain gets sent to the the Centers for Disease Control and Prevention (CDC).

The CDC laboratory is the only laboratory in the United States that can distinguish E. anophelis from E. meningoseptica.

Concerning treatment, Elizabethkingia is generally multi drug resistant; however, Wisconsin health officials say most of the isolates tested are susceptible to fluoroquinolones, rifampin and trimethoprim/sulfamethoxazole.

The investigation into the source of the outbreak continues. “Determining the source of the bacteria affecting patients in Wisconsin is a complex process,” Karen McKeown, the Wisconsin state health officer, said in a statement. The water supply has tested negative and no obvious pattern of medical procedures or common medical devices has emerged.

Other risk factors are being examined.

Although unusually large, the outbreak of Elizabethkingia should not concern the public. Dr. Safdar says, “I think the general public need not worry about it because even though it’s everywhere in the environment, it infects a very small proportion of people. I think the action really needs to be on the side of healthcare providers and facilities to immediately detect and identify it, and then report it to the division of public health to aid them in their investigation.”