The Knox County Health Department (KCHD) is concluding its investigation into a cluster of Escherichia coli (E. coli) O157 infections. Fifteen confirmed cases of E. coli O157 were reported to KCHD recently. All cases were among children, nine were hospitalized and seven developed a complication of the infection called Hemolytic Uremic Syndrome (HUS). Of the children who were hospitalized, one remains in fair condition at East Tennessee Children’s Hospital. Lab results from the Tennessee Department of Health have confirmed two different strains of E. coli O157 caused the children to become ill.

“While it is rare, it appears we had two sets of children sickened by two different strains of E. coli O157 at the same time. The epidemiological evidence overwhelmingly supported the two-source theory: consumption of raw milk and some type of contact, most likely indirect, with ruminant animals,” said KCHD Director Dr. Martha Buchanan. “The investigation revealed no definitive connections between the two sources or the two groups of ill children. And this is now supported by the state’s lab results confirming it was two different strains of E. coli O157.”

Ten of the 15 children consumed raw milk from French Broad Farm, Knox County, Tenn., the only common link among all ten children. The lab results have confirmed these children had the same strain of E. coli O157. The lab also confirmed that this strain is a DNA fingerprint match to the E. coli O157 found in cow manure samples collected from French Broad Farm.

To date, the lab did not find E. coli O157 in the raw milk samples. This is not uncommon, and it does not mean the milk consumed was free of contamination. E. coli bacterium do not distribute themselves uniformly in milk, meaning a portion of even the same glass of milk can be contaminated while another portion is not. This is one reason why raw milk is inherently risky. Due to the nature of E. coli and other pathogens that can be present, and even with the strictest safety precautions in place at a dairy, including testing the milk, there is no way to guarantee raw milk is safe for consumption. This is why health officials recommend the public consume only pasteurized milk and dairy products. Based on the dates when the children became ill (i.e., onset of symptoms) and allowing time for the milk to be distributed and time for incubation of the illness, officials believe the contamination event occurred in mid-May.

The only common link among the other five ill children was attending the same child care facility, Kids Place, Inc., Mascot, Tenn., where goats, a type of ruminant animal, are present. The lab results confirmed these five children had the same strain of E. coli O157. Additionally, the lab results showed this strain was a DNA fingerprint match to the E. coli O157 found in the goat fecal samples and one hay sample collected from the child care facility. To date, the lab did not find E. coli O157 in the other environmental samples from inside the facility. Again, this is not uncommon, and one reason testing environmental samples is only part of the disease investigation process.

E. coli O157 is naturally found in the intestinal tracts of many farm animals (ruminants), including healthy cattle, sheep and goats. Animals can carry E. coli O157 and shed it in their stool while still appearing healthy and clean. E. coli can contaminate the animals’ skin, fur, and the areas where they live and roam.

Both Kids Place, Inc. and French Broad Farm have fully cooperated throughout KCHD’s investigation, including sharing contact information of those who may be at risk, supporting sample collection and ceasing operations as requested. KCHD lifted the directive for Kids Place, Inc. on June 8, 2018, by following existing state and national procedures for infection control and mitigation at a permitted, regulated facility. KCHD lifted the health directive requesting French Broad Farm temporarily cease operations on June 14, 2018. While the investigation thus far has revealed no specific problems with French Broad Farm, the risk in consuming raw milk cannot be mitigated. The E. coli outbreak appears to be over as KCHD is not seeing ongoing transmission.

Following national epidemiological standards and methodology, the health department’s investigation included standardized and in-depth interviews; examination of all potential sources; analysis of symptom onset and incubation to aid in determining the timeline, potential exposures and the type of outbreak; and testing samples.

Most people become infected with E. coli O157 from contaminated food, such as undercooked ground beef, but E. coli O157 can also be passed directly to people from the stool of ruminant animals. Historically, the major source for human illness is cattle, which can carry E. coli O157 but show no signs of illness. E. coli O157 can also be spread from person to person via a fecal-to-oral route as these bacteria are invisible to the human eye.

While it is possible to get sick from many other foods, raw milk is one of the riskiest. As stated in the American Academy of Pediatrics policy statement on unpasteurized dairy, only an estimated 1 to 3 percent of dairy products consumed in the U.S. are unpasteurized. Yet between 1973 and 2009, these products accounted for 82 percent of the milk- or milk product-associated foodborne outbreaks reported to the Centers for Disease Control and Prevention. Health officials recommend the public consume only pasteurized milk, dairy products, juices and ciders.

Symptoms of E. coli infection vary for each person, but often include severe stomach cramps, diarrhea (often bloody) and vomiting. Some may have a low fever (less than 101˚F). Some infections are mild, but others can be severe. E. coli O157 can cause disease by making a Shiga toxin; these are referred to as Shiga toxin-producing E. coli or STEC. This can cause severe diarrhea and even life-threatening complications, especially in children, older adults, pregnant women and those with compromised immune systems. Approximately 5 to 10 percent of those diagnosed with a STEC infection develop a potentially life-threatening complication known as hemolytic uremic syndrome (HUS).

The Sky Valley Chronicle reports that the King County Health Department announced Friday afternoon it had closed two Redmond restaurants – I Love Sushi and Sodexo’s Café Mario both located at Nintendo of America at 4600 150th Ave NE, Redmond, WA.

The eateries were “Closed by a Public Health food inspector on July 5, 2018 at 5:30 pm due to the imminent health hazard of an ongoing suspected foodborne illness investigation,” said a news release from the health dept.

The health department, in a posting on its web page said that since July 2nd, “We have learned that four people (two King and two Snohomish County residents) have tested positive for STEC. All four consumed food from Café Mario in King County and work at the Nintendo of America campus in Redmond. Symptoms included abdominal cramps and bloody diarrhea. Illness onsets occurred during June 25–28, 2018. The four ill people consumed food from Café Mario on multiple days during June 18–22, 2018; one ill person also ate at I Love Sushi on June 19 and June 26, 2018, which is a food establishment that operates out of Café Mario once a week.”

On July 3rd, Seattle & King County Environmental Health investigators visited Café Mario. Inspections were completed for both Café Mario and I Love Sushi.

“At Café Mario, potential risk factors were identified, and corrective actions discussed with Café Mario’s management, including inadequate hand washing practices and improper cold holding temperatures of food,” said the statement. “At I Love Sushi, potential risk factors were also identified and discussed, including improper temperature storage of foods. Both restaurants were not open on July 4 due to it being a holiday.”

On July 5th investigators closed Café Mario and the onsite I Love Sushi food services. Both restaurants will remain closed until approved to reopen by Public Health.

Both food establishments will be required to complete a thorough cleaning and disinfection before reopening. Remaining food products are being held and environmental swabs were collected for laboratory testing.

“We are currently investigating whether any employees of these restaurants had a recent diarrheal illness. Investigators also reviewed with Café Mario’s management the Washington State Retail Food Code requirement that staff are not allowed to work while having vomiting or diarrhea,” said the Health Dept. statement.

Three of the four people who got sick tested positive for STEC by a healthcare provider. Further testing at the Washington State Public Health Laboratory is pending, including determining the genetic fingerprint and specific strain of STEC that caused the illnesses. The health dept. says the investigation is ongoing and it will provide more information as it becomes available.

The health dept. says STEC can cause serious illness. Anyone who ate at Café Mario and I Love Sushi at Nintendo of America during June 11, 2018 to July 5, 2018 and developed diarrhea (especially bloody diarrhea) within 10 days, should consult with their healthcare provider promptly to determine if testing is necessary.

As of June 27, 2018, 210 people infected with the outbreak strain of E. coli O157:H7 were reported from 36 states. A list of the states and the number of cases in each can be found on the Case Count Map page. Illnesses started on dates ranging from March 13, 2018 to June 6, 2018. Ill people ranged in age from 1 to 88 years, with a median age of 28. Sixty-seven percent of ill people were female. Of 201 people with information available, 96 (48%) were hospitalized, including 27 people who developed hemolytic uremic syndrome, a type of kidney failure. Five deaths were reported from Arkansas, California, Minnesota (2), and New York.

WGS analysis of isolates from 184 ill people identified antibiotic resistance to chloramphenicol, streptomycin, sulfisoxazole, tetracycline, and trimethoprim-sulfamethoxazole. Standard antibiotic resistance testing of eight clinical isolates by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory confirmed these findings. Isolates from four of those ill people also contained genes for resistance to ampicillin and ceftriaxone. These findings do not affect treatment guidance since antibiotics are not recommended for patients with E. coli O157 infections.

Epidemiologic, laboratory, and traceback evidence indicated that romaine lettuce from the Yuma growing region was the likely source of this outbreak.

The FDA and state and local regulatory officials traced the romaine lettuce to many farms in the Yuma growing region. The FDA, along with CDC and state partners, started an environmental assessment in the Yuma growing region and collected samples of water, soil, and manure. CDC laboratory testing identified the outbreak strain of E. coli O157:H7 in water samples taken from a canal in the Yuma growing region. WGS showed that the E. coli O157:H7 found in the canal water is closely related genetically to the E. coli O157:H7 from ill people. Laboratory testing for other environmental samples is continuing. FDA is continuing to investigate to learn more about how the E. coli bacteria could have entered the water and ways this water could have contaminated romaine lettuce in the region.

Most of the children are known to have consumed raw milk from a local cow-share dairy. Due to possible contamination with E. coli O157 and out of an abundance of caution, KCHD advises the public not to consume raw milk or any other unpasteurized products from French Broad Farm in Mascot, Tenn. at this time. Officials also recommend consumers dispose of all raw milk and unpasteurized products they may have from this farm.

Any further exposure to the farm animals in question has been mitigated as the facility is not currently operating. Therefore, no further directive on that potential source is necessary.

“Bacteria, like E. coli, cannot be seen with the naked eye,” said KCHD Director Dr. Martha Buchanan. “For some perspective, roughly 1,800 can fit on the head of a pen, and it only takes about 10 to make you sick.”

Raw milk and other unpasteurized products can contain harmful bacteria, including E. coli O157. While it is possible to get sick from many other foods, raw milk is one of the riskiest. E. coli can also be found in the feces of cattle, goats, sheep and other ruminant animals. Historically, the major source for human illness is cattle, which can carry E. coli 0157 and show no signs of illness. These bacteria, however, can cause severe diarrhea and even life-threatening complications for humans, especially children, older adults, pregnant women and those with compromised immune systems. Information on preventing E. coli can be found on the CDC’s website.

Symptoms of E. coli infection vary for each person, but often include severe stomach cramps, diarrhea (often bloody), and vomiting. Some may have a low fever (less than 101 ̊F). Some infections are mild, but others can be severe.

Summary

Public Health is investigating an outbreak of Shiga toxin-producing E. coli (STEC) associated with multiple Homegrown restaurants.

Illnesses

Since May 23, 2018, we have learned that four people (one is a Snohomish County resident) have tested positive for STEC after consuming food from three different Homegrown restaurants in King County. Symptoms included abdominal cramps and diarrhea, with one person reporting bloody diarrhea.

All four ate the chicken pesto sandwich from one of the following locations: Redmond, Kirkland or Seattle (Westlake Ave). Of the four ill persons, three are adults and one is a child. Illness onsets occurred during April 24–May 6, 2018. Exact meal dates are not known for all four persons, but known meal dates occurred during April 24–26, 2018.

Public Health actions

On May 24, 2018, Environmental Health investigators visited the three Homegrown locations where the ill persons reported eating. During the field inspections, potential risk factors, including handwashing facilities violations at two of the three locations, and a cold holding temperature violation at one of the three locations, were identified and discussed with the restaurant managers.

We are also investigating the various ingredients of the chicken pesto sandwich. All Homegrown locations in King County have stopped selling this particular sandwich while the investigation is ongoing. Any remaining products related to this sandwich have been put on hold in case testing is warranted. The three restaurants were required to complete a thorough cleaning and disinfection. Investigators also reviewed the requirement that staff are not allowed to work while having vomiting or diarrhea.

Investigators revisited the restaurants on May 25, 2018, to confirm cleaning and disinfection were completed appropriately. We are currently investigating whether any employees had a recent diarrheal illness. We will post updates once we have further details.

Laboratory testing

Three of the four people who got sick tested positive for STEC O26. All three had the same genetic fingerprint, suggesting that they have a common source of infection; genetic fingerprinting for the other ill person cannot be completed. This genetic fingerprint has never been seen in the United States before, making it unique to this outbreak.

According to the CDC, as of May 15, 2018, 172 people infected with the outbreak strain of E. coli O157:H7 have been reported from 32 states.  Alaska (8), Arizona (8), California (39), Colorado (3), Connecticut (2), Florida (1), Georgia (4), Idaho (11), Illinois (2), Iowa (1), Kentucky (1), Louisiana (1), Massachusetts (3), Michigan (5), Minnesota (12), Mississippi (1), Missouri (1), Montana (8), Nebraska (1), New Jersey (8), New York (5), North Dakota (2), Ohio (6), Oregon (1), Pennsylvania (21), South Dakota (1), Tennessee (3), Texas (1), Utah (1), Virginia (1), Washington (7), and Wisconsin (3).

Illnesses started on dates ranging from March 13, 2018 to May 2, 2018.

Ill people range in age from 1 to 88 years, with a median age of 29. Sixty-five percent of ill people are female. Of 157 people with information available, 75 (48%) have been hospitalized, including 20 people who developed hemolytic uremic syndrome, a type of kidney failure.

One death was reported from California.

Illnesses that occurred after April 21, 2018, might not yet be reported due to the time it takes between when a person becomes ill with E. coli and when the illness is reported. This takes an average of two to three weeks.

According to the FDA, the last shipments of romaine lettuce from the Yuma growing region were harvested on April 16, 2018, and the harvest season is over. It is unlikely that any romaine lettuce from the Yuma growing region is still available in people’s homes, stores, or restaurants due to its 21-day shelf life. The most recent illnesses reported to CDC started when romaine lettuce from the Yuma growing region was likely still available in stores, restaurants, and in peoples’ homes.

The FDA has identified Harrison Farms of Yuma, Arizona, as the grower and sole source of the whole-head romaine lettuce that sickened several people in an Alaskan correctional facility, but has not determined where in the supply chain the contamination occurred.

The traceback investigation indicates that the illnesses associated with this outbreak cannot be explained by a single grower, harvester, processor, or distributor. While traceback continues, the FDA will focus on trying to identify factors that contributed to contamination of romaine across multiple supply chains.  The agency is examining all possibilities, including that contamination may have occurred at any point along the growing, harvesting, packaging, and distribution chain before reaching consumers.