Food poisoning is a disease caused by the ingestion of bacterial toxins. However, diseases from food more commonly occur through direct invasion of bacteria into the body. Therefore, the common term “food poisoning” more accurately means bacterial gastrointestinal diseases that are caused by the ingestion of toxins.
One of the main causes of bacterial gastrointestinal disease from the ingestion of toxins, namely food poisoning, is Staphylococcus. This is a bacteria that is commonly found in the human skin and causes infections. Contamination with Staphylococcus can occur if people cook with unclean hands with cuts or ruptured skin.
Staphylococcus produces a toxin called enterotoxin. Ingestion of this toxin produces systemic symptoms such as diarrhea, nausea, headaches and dizziness, more than abdominal pain. This is because the toxins irritate the stomach and are absorbed into the body, causing systemic symptoms. The toxins do not disappear even after reheating or boiling food, which is why eating reheated food can cause symptoms of food poisoning. Other diseases caused by ingestion of toxins include botulinous food poisoning.
The most well-known example of bacterial gastrointestinal disease caused by invasion of bacteria into the body system is dysentery. Dysentery is caused by invasion of the gastrointestinal mucous membrane by a bacteria called Shigella. It is associated with diarrhea, abdominal pain and fever. There may be blood or sticky mucous in the stool. It is a serious condition with complications that include renal failure and hemolytic anemia, and in severe cases, can lead to sepsis. It is also highly contagious and often leads to pandemics.
More recently, an E. coli bacteria that produces similar symptoms to dysentery has been found, which is causing concern. This bacteria, which is called E. coli 0157, is mainly transferred through contamination of infected stool of animals, such as cows. It is mainly contracted through the ingestion of uncooked hamburger meat. Hamburger patties are made from minced meat, so there is a greater possibility of bacteria contamination. Ingestion of incompletely cooked meat that was contaminated with this bacteria can cause illness. In Japan, there was a case of mass infection of elementary school children by ingestion of vegetables.
Bacterial gastrointestinal disease
The most common type of bacterial gastrointestinal disease is infections that cause diarrhea, which is not as serious as dysentery. These include infections by Salmonella, Campylobacter and Yersinia as well as other microorganisms. Infection is associated with abdominal pain, diarrhea and fever, but complications or hematochezia (bloody stool) are uncommon. Mild cases of dysentery present symptoms similar to these infections, and serious infective diarrhea can present symptoms like those of dysentery.
Vibrio sepsis is caused by ingestion of contaminated food, but its clinical symptoms are quite different. Vibrio is a type of bacteria from the sea that reproduces actively when the temperature of seawater rises during summer, infecting other living organisms. It is often seen in patients with chronic diseases such as cirrhosis of the liver, chronic liver disease, diabetes or alcohol dependency who have ingested raw seafood. It is associated with blister formation on the legs, bleeding, fever and sepsis. The disease progresses very rapidly, and can be fatal, causing death within a few days.
Food poisoning from Staphylococcus is treated by symptomatic relief such as prevention of vomiting and rest. Dysentery requires antibiotic treatment and intravenous fluids, so hospital admission is recommended. Other infective diarrhea is treated easily with fluid and electrolyte replacement and leads to rapid recovery within a few days. Antibiotics may be required in severe cases (if experiencing fever, abdominal pain, hematochezia or more than four episodes of diarrhea per day). Vibrio sepsis is only treated by rapid and focused treatment, such as leg amputation.
To prevent bacterial gastrointestinal diseases in summer, you should watch what you eat and drink. Boil water before drinking, and only eat cooked food. If you do not have boiled water, you can buy bottled water or other drinks. Eat fruit that you can remove the skin from. To prevent food poisoning by Staphylococcus you should wash your hands well before cooking. Those with cuts or ruptured skin on the hands should avoid cooking. It is unsafe to reheat leftover foods, so avoid eating leftovers. Those with chronic diseases or diabetes, or heavy drinkers should not eat raw seafood during summer.
By Ha Young-eun
The author is a doctor at Samsung Medical Center’s division of infectious diseases and an assistant professor at Sungkyunkwan University’s School of Medicine. ― Ed.