Multnomah County and Oregon State Public Health are investigating multiple cases of diarrheal illness caused by Shiga toxin-producing E. coli (STEC) from a single childcare center in Portland with onsets of illness ranging from March 2-6th. Sub-typing from these cases is pending and the cause, or causes, of this local outbreak have not yet been determined. However, one of the STEC cases in this cluster consumed I.M. Healthy Soy Nut Butter, a product linked to a national outbreak of STEC O157:H7. This product was recalled on March 7, 2017 (see here for more information).
Most persons with STEC report bloody stools, however, mild, non-bloody diarrheal illness and asymptomatic infections can occur. Symptoms usually begin 3-4 days after exposure (range 1 to 10 days) and include abdominal pain and cramping. Nausea and vomiting are also common but fever is generally low grade or absent.
Treatment for STEC is supportive; neither antibiotics nor anti-diarrheal agents should be used since they may worsen illness. Most people recover within 5–10 days but 10-20% can develop hemolytic uremic syndrome (HUS) characterized by microangiopathic hemolytic anemia, renal injury, and low platelet count. Emerging evidence suggests that dehydration is an independent risk factor for mortality and renal failure. Volume expansion with isotonic fluids during the diarrheal phase may limit renal failure and should be considered.
Action for Clinicians
Public health officials urge you to consider STEC in your differential diagnosis for all persons with compatible symptoms especially when there is a history of consumption of I.M. Healthy SoyNut Butter, I.M. Healthy Granola products, or childcare exposure.
- In patients with symptoms compatible with STEC infection, collect a stool specimen for pathogen testing that at minimum will detect STEC or E. coli O157:H7 (various methods are currently used by different laboratories).
- If STEC is detected then also obtain a complete blood count, serum electrolytes, BUN, and creatinine as a screen for hemolytic uremic syndrome (HUS) and consider consultation with a nephrologist.
Secondary spread is a serious concern with STEC infections as bacteria can be shed for weeks. Because lab confirmation can be delayed, please educate suspected as well as confirmed cases of STEC to stay home while sick, to wash hands after toileting or handling diapers, and to not handle food for others. Suspected cases should be restricted from attendance at school or childcare and from food handling jobs until asymptomatic.
For more information about STEC, see http://www.cdc.gov/ecoli/index.html. Please report suspected cases of STEC or HUS immediately to the county public health department of the patient’s residence.
Clackamas County Public Health: 503-655-8411
Multnomah County Public Health: 503-988-3406
Washington County Public Health: 503-846-3594