What causes foodborne disease?
Last reviewed: 17.10.2021
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Foodborne toxic infections combine a large number of etiologically different, but pathogenetically and clinically similar diseases.
Combining foodborne infections into a separate nosological form is caused by the need to unify measures to combat their spread and the effectiveness of the syndromic approach to treatment.
The most common food poisoning is caused by the following conditionally pathogenic microorganisms:
- family Enterobacteriaceae genus Citrobacter, Klebsiella, Enterobacter, Hafnia, Serratia, Proteus, Edwardsiella, Erwinia;
- family Micrococcaceae genus Staphilococcus;
- family Bacillaceae genus Clostridium, genus Bacillus (including species B. Cereus );
- family Pseudomonaceae genus Pseudomonas (including the species Aeruginosa);
- family Vibrionaceae genus Vibrio, species of NAG-vibrios (non-agglutinating vibrios), V. Parahaemoliticus.
Most of the above bacteria live in the intestines of practically healthy people and many representatives of the animal world. The causative agents are resistant to the action of physical and chemical environmental factors; are capable of reproduction both in living organism conditions and outside it, for example in food products (over a wide range of temperatures).
Pathogenesis of food toxic infections
Food toxic infections occur at 2 conditions:
- infecting dose - not less than 10 5 -10 6 microbial bodies per 1 g of substrate;
- virulence and toxigenicity of strains of microorganisms.
The main importance is the intoxication of bacterial exo- and endotoxins of pathogens contained in the product.
When bacteria are destroyed in food and gastrointestinal tract, endotoxin is released, which stimulates the production of cytokines, activates the hypothalamic center, favors fever, disturbs vascular tone, changes in the microcirculation system.
The complex effect of microorganisms and their toxins leads to local (gastritis, gastroenteritis) and general (fever, vomiting, etc.) signs of the disease. The excitation of the chemoreceptor zone and the vomiting center located in the lower part of the ventricle IV bottom, with impulses from the vagus and sympathetic nerves, is important. Vomiting is a protective reaction aimed at removing toxic substances from the stomach. With prolonged vomiting, it is possible to develop glypohloremic alkalosis.
Enteritis is caused by enterotoxins released by the following bacteria: Proteus, B. Cereus, Klebsiella, Enterobacter, Aeromonas, Edwardsiella, Vibrio. Due to the violation of synthesis and equilibrium of biologically active substances in enterocytes, an increase in the activity of adenylate cyclase is accompanied by an increase in the synthesis of cAMP. The energy released in this case stimulates the secretion function of the enterocytes, as a result, the yield of the isotonic, protein-poor liquid in the lumen of the small intestine is enhanced. There is profuse diarrhea, leading to violations of water-electrolyte balance, isotonic dehydration. In severe cases, the development of dehydration (hypovolemic) shock is possible.
The colitis syndrome usually appears in mixed infections involving pathogenic flora.
In the pathogenesis of staphylococcal food poisoning, the effect of enterotoxins A, B, C1, C2, D and E.
The similarity of pathogenetic mechanisms in food toxic infections of different etiology determines the commonness of clinical symptoms and determines the scheme of therapeutic measures.