We have recently been reporting on the rare E. coli strain O111 that was responsible for an Oklahoma outbreak that sickened 313 and killed one in the largest O111 outbreak in American history. Seventeen people required dialysis.
The Centers for Disease Control and Prevention (CDC) say E. coli O111 can be deadly and is gaining public health official attention. From 1990 to 2007, O111 was linked to 10 U.S. outbreaks. Of those, four of were linked to food. Prior to this, the largest such outbreak occurred in New York in 2004 when unpasteurized apple cider sickened 212.
Some E. coli strains are necessary for digestion; some are harmful, even deadly, such as the very rare and toxin-producing strain E. coli O111. Typically, the virulent, sometimes deadly E. coli O157:H7 is found to be responsible in E. coli-related food-borne illness outbreaks; both deadly strains are among those in groups called Verocytotoxigenic E. coli (VTEC) and Shiga Toxin-producing E. coli (STEC), linked to food poisoning and that are very serious and can cause fatal blood poisoning, cystitis, deadly septicemia, and death.
O111 is one of just a few non-O157:H7 STECs that have caused 22 reported illness outbreaks in the U.S. from 1990 to 2007, the CDC says. Food caused 10 of the outbreaks. Illnesses caused by non-O157:H7 STECs/VTECs are usually milder than those caused by O157, the CDC says; however, some are as severe and can cause the kidney failure and other serious symptoms of O157, such as what was seen in the Oklahoma O111 outbreak.
While the number of reported non-O157 outbreaks appears small, it is possible that many go unreported because doctors do not look for non-O157 E. coli. “There’s a significant possibility that illnesses and outbreaks have been missed,” says Elisabeth Hagen of the Office of Public Health for the U.S. Department of Agriculture. The CDC estimates over 25,000 non-O157 STEC/VTEC infections occur annually in the U.S., about one-third the number of O157:H7 infections. In the US, E. coli is the leading cause of food-borne illness, accounting for about 73,000 infections and 61 deaths.
Research reveals other E. coli types may be more prevalent than first thought, according to Richard Raymond, the USDA’s undersecretary for food safety, citing a recent study in Nebraska in which nearly 50 percent of E. coli infections there were non-O157:H7s. Other countries have seen the same, Hagen says. Cattle are E. coli’s primary source and while there are many strains, only O157:H7 is routinely tested for by the meat industry and the USDA. O157:H7 was identified in the 1980s and declared an adulterant in ground beef in 1994. Once described as an adulterant, an E. coli strain would cause recalls in the future.
The USDA will begin testing ground beef for six other E. coli types, including O111, that are causing most of the non-O157 infections, Hagen says. Testing may begin within months, she adds. It remains unclear if more nonO157 infections are occurring or being identified more often, Hagen says. The USDA wants to determine how prevalent they are and find ways to reduce consumer risk.
