In the Minnesota E. coli O157:H7 outbreak linked to raw milk from the Hartman Dairy Farm, state health officials have identified four outbreak cases, all of whom were hospitalized for treatment of their injuries. Sadly, as Mike Hughlett reported in the Minnesota Star Tribune today, an area toddler, one of the victims, remains hospitalized, having developed hemolytic uremic syndrome (HUS).
Hemolytic uremic syndrome:
The chain of events leading to HUS begins with ingestion of Stx-producing E. coli (e.g., E. coli O157: H7) in contaminated food, beverages, animal to person, or person-to-person transmission. These E. coli rapidly multiply in the intestine causing colitis (diarrhea), and tightly bind to cells that line the large intestine. This snug attachment facilitates absorption of the toxin into the intestinal capillaries and into the systemic circulation where it becomes attached to weak receptors on white blood cells (WBC) thus allowing the toxin to “ride piggyback” to the kidneys where it is transferred to numerous avid (strong) Gb3 receptors that grasp and hold on to the toxin.
Organ injury is primarily a function of Gb3 receptor location and density. Receptors are probably heterogeneously distributed in the major body organs, and this may explain why some patients develop injury in other organs (e.g., brain, pancreas).
Once Stx attaches to receptors, it moves into the cell’s cytoplasm where it shuts down the cells’ protein machinery resulting in cellular injury and/or death. This cellular injury activates blood platelets and the coagulation cascade, which results in the formation of clots in the very small vessels of the kidney, resulting in acute kidney injury and failure.
The red blood cells undergo hemolytic destruction by Stx and/or damage as they attempt to pass through partially obstructed microvessels. Blood platelets (required for normal blood clotting), are trapped in the tiny blood clots or are damaged and destroyed by the spleen.
Minnesota law on the sale of raw milk:
Minnesota law prohibits most raw milk sales, except for occasional purchases directly at the farm where the milk is produced. The Minnesota Department of Agriculture investigates complaints and cases of food-borne illness associated with the sale of raw milk. Enforcement actions can be taken in cases when sales of raw milk are identified and people become ill from consuming the raw milk.