Mode of e.coli contamination

The bacterium Escherichia coli or E.Coli made headlines in 2022 after contaminating Buitoni pizzas and causing serious food infections in children, two of whom died. What symptoms should alert? In which foods especially? What to do ? What are the treatments ?

The E.coli bacteria or Escherichia Coli is present in the intestine humans and some animals. Some strains dangerous can be found in food and lead to serious infections. These pathogenic bacteria called “EHEC” colonize the digestive tract of the patient then release toxins (Shigatoxins) which will induce vascular lesions at the intestinal, renal and cerebral levels, which explains the clinical manifestations with renal or neurological complications (haemolytic-uremic syndrome (SHU) mainly in young children Where thrombotic microangiopathy (MAT) in adults). In January 2022, several cases of SHU have been confirmed in children following the Buitoni frozen pizza consumption contaminated with Shiga-toxin producing E.coli bacteria. Two children are d

What is E.coli bacteria?

Escherichia Coli or “E.coli” is a bacteria present in the intestine humans and certain animals, especially ruminants. Useful, it prevents other bacteria from colonizing the intestinal flora and causing disease. When they are in the intestine, the majority of its strains are harmless and cause no symptoms. Some, however, are pathogens and cause intestinal disorders. E. coli bacteria can cause urinary tract infections (cystitis). These mostly affect women because of their anatomy. In effect, in the woman, the anus is close to the urinary tract, which is therefore easily colonized by bacteria. In rare cases, the bacteria can infect other organs such as the vesicle biliary. She can also cause meningitis in newborns.

What are EHEC bacteria?

We speak of EHEC bacteria to designate the bacteria “Enterohaemorrhagic Escherichia Coli”. It is a type of escherichia coli bacteria pathogens which produce shigatoxins. The most monitored in France in food are: O157:H7, O26:H11, O103:H2, O145:H28, and O111:H8. The EHECs colonize the digestive tract of the patient then release toxins (Shigatoxins) which will induce vascular lesions at the intestinal, renal and cerebral levels, which explains the clinical manifestations with renal or neurological complications (haemolytic-uremic syndrome (SHU) mainly in young children or thrombotic microangiopathy (MAT) in adults). The populations having a higher than average probability of developing symptoms or severe forms of the disease are the children under 15 (especially under 5 years old) and the elderly. The main reservoirs of these bacteria are the cattle and sheep. “The contamination of food of animal origin occurs in particular at the slaughterhouse for meat (skinning or evisceration of animals) or in dairy farming during milking” explains the Food Agency in France (handles). In France, monitoring of EHEC infections is based on the surveillance of HUS cases in children under 15 years of age. It is coordinated by French public health. EHEC infections are microbiologically confirmed by the CNR and its associated laboratory.

How many epidemics caused by E.coli in France?

In France, five outbreaks of EHEC infections were detected and investigated between 2011 and 2018:

  • an outbreak of O104:H4 linked to germinated seeds consumed raw in 2011,
  • three outbreaks of O157:H7/H- linked to ground beef in 2011 and 2012 and raw milk cheese in 2013,
  • and an O26 outbreak in a raw milk cheese in 2018.

What cooking temperature to kill E.coli bacteria?

ANSES recommends thorough cooking of minced meat or minced meat products consumed by young children or the elderly: a core temperature of 70°C for 2 minutes must be achieved when cooking beef patties. After cookingthe inside of the steak should be gray-brown and in no case still red or rosé. This brown-gray color indicates that the proteins at heart have been cooked, which also destroys bacteria possibly present as EHECs.

► On the grill (+260°C): a frozen minced steak weighing 100 grams will be “well cooked through” after 13 minutes of cooking with 3 successive turns at regular time intervals.

► Under the same conditions, a fresh or defrosted minced steak will be “well cooked through” after 8 minutes of cooking.

The contamination of the intestines is done by fecal-oral route. Transmission to humans is often via meat contaminated and eaten raw or undercooked. The consumption of fruits and vegetables washed with contaminated water, raw milk, or bathing in dirty water, for example, can also cause these infections. “A growing number of outbreaks are associated with the consumption of fruits and vegetabless (sprouted seeds, spinach, lettuce, raw cabbage, salads) for which the contamination could be due to contact with faeces of domestic or wild animals at some stage of cultivation or handling” also reports WHO.

Mode contamination by pathogenic E.coli bacteria (EHEC) © SMAC-Corsica

What is the incubation period?

The incubation period ranges from 3 to 8 days with a median duration of 3 to 4 days.

What are the symptoms of an E.coli infection?

When ingested, it can cause intestinal infections and therefore diarrhea. These can sometimes be bloodyassociated with feverof the vomitingof the abdominal pain, dehydration (the classic symptoms of gastroenteritis). In this case, contact your doctor immediately or go to the nearest emergency department. The incubation period is 4 days on average. Urinary tract infections as for them, they can manifest themselves by a frequent urination, pain in the lower abdomenburning when urinating and the presence of blood in the urine.

What is the danger of the bacterium escherichia coli?

Most patients recover from an Escherichia Coli infection within 10 days, but for some the infection can progress to a serious, life-threatening form, such as haemolytic uremic syndrome (HUS). This is characterized by acute renal failure, hemolytic anemia and thrombocytopenia. (decrease in platelets).

The diagnosis is based on a clinical assessment (manifestations and symptoms of the disease, aspect of the stool), a cytobacteriological examination of the urineif urinary tract infection (ECBU) (it is advisable to carefully apply the rules of prior disinfection of the urethral meatus and to collect only the “jet medium” not the first), complete blood count, a blood ionogram, urea and creatinine levels (kidney damage) and possibly a blood culture in the presence of fever. Coproculture (stool analysis) is useful in case of persistent diarrhoea.

What are the treatments for Escherichia coli bacteria?

► In case of intestinal infection: Dehydration related to diarrhea and vomiting can be very important, especially in infants and the elderly. Therefore, in the majority of casesthe only treatment is to drink plenty of water. If the symptoms affect a fragile person (child, elderly, chronically ill), if they include bloody diarrhea or if they last more than two days, consult a doctor. This one can prescribe antibiotics if he deems it necessary. “E.coli is part of the balance of the intestinal microbiota and lAntibiotic prescription should never be systematic due to the risk of disruption of the microbiota, the cause of many pathologies“, however, advises Dr Anne-Christine Della Valle, general practitioner.

► In case of urinary tract infection: Consult your doctor at the first symptoms, he can prescribe antibiotics and / or give you advice on how to make it disappear. the recommended treatment for uncomplicated E. coli cystitis in young women is fosfomycin orally in a single dose (“minute treatment”). Acquired resistance to fosfomycin remains rare, despite frequent use. This reduces the use of quinolones and cephalosporins which select strains resistant to these antibiotics useful in the treatment of severe infections. the treatment of pyelonephritis and bacteremia appeals to 3rd generation cephalosporins, aminoglycosides or fluoroquinolones. The treatment of neonatal meningitis is based on the combination of a 3rd generation cephalosporin IV at high doses (meningeal doses) and an aminoglycoside.

As part of the prevention of hemolytic-uremic syndrome in children, two categories of food are in particular in question: minced meat and the raw milk products. To avoid serious foodborne infectionaccording to the recommendations of the Ministry of Health :

  • The minced meat by the butcher on request must be consumed during the dayand frozen ground beef must not have undergone a break in the cold chain or thawing.
  • Never thaw at room temperature.
  • The cooking meats, especially minced beef, must be carried out to heart. To do this, you must ensure that the meat is cooked in the center and that it is no longer dew.
  • the raw milk and cheeses made from raw milk should not be consumed by young children and in particular those under 5 years old; prefer cooked pressed cheeses (such as Emmental, Comté, etc.), spreadable processed cheeses and pasteurized milk cheeses.
  • the Hand washing should be systematic before meal preparationwhen leaving the toilet or after changing an infant’s diapers.
  • The vegetables, fruits and aromatic herbs should be thoroughly washed, especially when eaten raw.
  • The cooked meals and leftover food must be sufficiently reheated and consumed quickly.
  • The children should not drink untreated water (well water…)
  • Store raw foods separately from cooked or ready-to-eat foods.
  • Kitchen utensils and worktops should be thoroughly washed, especially when they have previously come into contact with raw meat.

To avoid urinary tract infectionsit is recommended to drink at least 1.5L of water per day, to wipe from front to back after a bowel movement, and to urinate just before and after each sexual intercourse.

Thanks to Dr Anne-Christine Della Valle, general practitioner. Sources: Escherichia coli/Shigella. SFM-Microbiology.org

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