What is Foodborne Disease Infection?
Foodborne diseases – acute infectious diseases caused by opportunistic bacteria producing exotoxins. When microorganisms get into food, toxins accumulate in them, which can cause poisoning in humans.
Brief historical information
For many centuries, mankind has been known that eating poor-quality products, especially meat, can lead to the development of vomiting and diarrhea. After the description of P.N. Lashchenko (1901) of the clinical picture of staphylococcal food intoxication, it was found that diseases with diarrhea syndromes and intoxication can cause opportunistic bacteria. As a result of the work of domestic researchers, these diseases are attributed to the group of foodborne diseases.
Causes of Foodborne Infections
Foodborne toxicoinfection causes a large group of bacteria; the main pathogens are Staphylococcus aureus, Proteus vulgaris, Bacillus cereus, Clostridium perfringens, Clostridium difficile, representatives of the genera Klebsiella, Enterobacter, Citrobacter, Serratia, Enterococcus, etc. Pathogens are widely distributed in nature, have pronounced resistance and are able to reproduce in environmental objects. All of them are permanent representatives of the normal microflora of the intestines of humans and animals. Often, the diseased fail to isolate the pathogen, since the clinical picture of foodborne toxicoinfections mainly determines the effect of microbial toxic substances. Under the influence of various environmental factors, conditionally pathogenic microorganisms change such biological properties as virulence and resistance to antibacterial drugs.
The source of infection is various animals and people. Most often these are persons suffering from purulent diseases (panaritiums, tonsillitis, furunculosis, etc.); among the animals are cows and sheep suffering from mastitis. All of them secrete the pathogen (usually staphylococcus), which enter the food products during their processing, where bacteria multiply and accumulate. Epidemiological danger are both sick and carriers of pathogens. The period of contagion of patients is small; regarding the timing of bacteriocarrier data are contradictory.
The causative agents of other toxicoinfections (C. perfringens, B. cereus, etc.) people and animals secrete into the external environment with feces. The reservoir of a number of pathogens can be soil, water, and other environmental objects contaminated by animal and human excreta.
The transmission mechanism is fecal-oral, the main transmission mode is food. For the emergence of foodborne diseases caused by opportunistic bacteria, a massive dose of pathogens or a certain time for its reproduction in food products is necessary. Most often, food toxicoinfections are associated with contamination of milk, dairy products, canned fish in oil, meat, fish and vegetable dishes, as well as confectionery products containing cream (cakes, pastries). The main product involved in the transfer of clostridia is meat (beef, pork, chicken, etc.). The preparation of some meat dishes and products (slow cooling, repeated heating, etc.), the conditions for their implementation contribute to the germination of spores and the propagation of vegetative forms. Various objects of the external environment are involved in the relay transmission of the pathogen: water, soil, plants, household items and patient care. Products containing staphylococcal and other enterotoxins, in appearance, smell and taste do not differ from benign ones. Diseases occur in the form of sporadic cases and outbreaks. They are more often recorded in the warm season, when favorable conditions are created for the reproduction of pathogens and the accumulation of their toxins.
The natural susceptibility of people is high. Usually, most people who have consumed contaminated food will become ill. In addition to the properties of the pathogen (sufficient dose, high virulence) for the development of the disease requires a number of contributing factors from both the microorganism and the microorganism (reduced resistance, the presence of associated diseases, etc.). More susceptible individuals at risk: newborns, weakened individuals, patients after surgery, or long-term antibiotics, etc.
Major epidemiological signs. Diseases caused by conditionally pathogenic microorganisms are widespread. Outbreaks are family-like or when food contaminates in catering establishments, diseases can be dispersed among the population. The number of cases determines the number of people who consumed a contaminated food product, and can vary significantly. In particular, group diseases are very characteristic among passengers of ships, tourists and members of children’s and adult organized groups. Outbreaks are usually explosive in nature. Any features on the socio-age and gender composition is not revealed. Diseases are more often recorded in the summer. Depending on the type of food product among the sick, children or adults predominate. In addition to food and household outbreaks are possible, in most cases occur in a hospital setting. Outbreaks of nosocomial infections caused by C. difficile are associated with prolonged use of antibiotics. In water outbreaks, as a result of fecal contamination, other pathogens of acute intestinal infections are secreted simultaneously with opportunistic microorganisms simultaneously.
Pathogenesis during Foodborne Disease Infection
A common property for all causative agents of foodborne toxicoinfections is the ability to produce various types of exotoxins (enterotoxins) and endotoxins (lipopolysaccharide complexes). It is thanks to the peculiarities of the action of these toxins that a certain peculiarity is noted in the clinical manifestations of food toxicoinfections caused by various pathogens. The exceptionally important role of bacterial toxins in the development of foodborne diseases and indicates a relatively short incubation period of the disease.
Depending on the types of toxins, they can cause hypersecretion of fluid into the intestinal lumen, clinical manifestations of gastroenteritis, and systemic manifestations of the disease in the form of intoxication syndrome.
Bacterial toxins realize their action through the production of endogenous mediators (cAMP, PG, interleukins, histamine, etc.), which directly regulate structural and functional changes in organs and systems detected in patients with foodborne toxicoinfection.
The similarity of the pathogenetic mechanisms of food toxicoinfections of various etiologies determines the commonality of the basic principles in the approaches to therapeutic measures in these diseases, as well as in salmonellosis and campylobacteriosis.