Escherichiosis is an infectious disease caused by gram-negative anaerobic rod-shaped bacteria by Escherichia. The most famous representative of the species is E. coli, which abounds in the intestinal mucosa of all warm-blooded animals, including rights. Under normal conditions, most of the subspecies of Escherichia are symbiotic or commensal, not only not dangerous to the human body, but also beneficial, because bacteria synthesize some biologically active compounds (for example, vitamin K), partially break down the fiber and prevent intestinal introduction and reproduction all kinds of pathogenic bacteria.
However, many bacteria of the Escherichia species are prone to mutations and horizontal gene transfers, resulting in such features, because of which a harmless previously intestinal flora can pose a significant danger and cause escherichiosis. Mutations can occur both in the host organism and outside the intestine, since the escherichia can persist in the fecal contamination of water, soil, and other external environment of the person. In experimental cultivation, Escherichia managed to prove not only the change in individual properties of bacteria in mutations, but also the formation of new species of Escherichia coli.
Causes and causative agents of escherichiosis
The species diversity of pathogens and the ability to mutate are the main reason why escherichiosis can occur with a wide variety of manifestations and in varying degrees of severity. For the same reason, so far no specific treatment has been developed, nor preventive vaccines that prevent escherichiosis even during mass outbreaks. In 2009, a report appeared about the development of a vaccine at the University of Michigan against a single pathogenic strain of Escherichia, but no further development of the statement, but researchers around the world are working on this problem.
Escherichiosis can be caused by intestinal and parasitic rods that have got into the body from outside, developed certain aggressive properties, as well as representatives of their own flora that have changed under the influence of some factors.
It was believed that the intestine of a newborn is colonized with E. coli by the end of the second day of life, but a number of researchers claim that this process begins in the intrauterine period. Accordingly, mothers-bacilli commensals, already at this stage, may have some influence on the work of the baby's intestines.
Escherichia - small (up to 1 micron) bacteria in the form of a rod with slightly curved and rounded ends. Optimum conditions for their dwelling and reproduction - anaerobic environment with a temperature regime of about 37 ° C, which makes the digestive tract warm-blooded an ideal place for the life of bacilli. But some strains remain viable even at a higher temperature (up to 50 ° C). Some strains of Escherichia coli have flagella, that is, they are able to move independently.
All bacilli that cause escherichiosis, survive long after drying, in many food products are rapidly developing with the formation of massive colonies, especially for milk.
The coexistence of the Escherichia and the human body is usually commensal, that is, the commensal (bacterium) receives protection from external influences and nutrition from the person (master), but does not enter into other types of contacts. In this case, commensal benefits from such a joint habitat, and the owner, at least, does not experience any harm. But when the intestinal rods under the influence of any factors change properties and become aggressive towards intestinal tissues, they cause irritation of the mucosa, inflammatory reaction, toxic effect - escherichiosis develops.
Not all Escherichia show pathogenic properties, therefore they are divided into non-pathogenic, conditionally pathogenic and pathogenic strains. But even such a division does not exactly reflect the ability to cause escherichiosis, since there are no obvious morphological differences in these three categories. Whether the infectious disease develops or not depends on the structure of the antigen located on the bacterial membrane, and the structure of the antigen protein can change during the mutations, respectively, and the escherichiosis can develop under the influence of the non-pathogenic genus in the usual conditions of E. coli.
Nevertheless, it is the structure of the antigen that is the basis of the classification that distinguishes the five main groups of the pathogen. Each group is characterized by distinctive symptoms and manifestations of the pathogen process.
Symptoms and signs of escherichiosis
Since some species of E. coli cause a number of lesions and associated manifestations that differ from the symptoms caused by other strains, it made it possible to distinguish five groups of bacteria that provoke intestinal esherichiosis.
• A group of strains causing enteropathogenic escherichiosis is characterized by cytolytic action on the epithelial membrane of the intestine, which is manifested by microvilli damage, irritating action, abundant release of glandular mucus cells as a protective reaction. Escherichiosis will be accompanied by diarrhea, especially in children, liquid mucosal layers are found in liquid stools, and even the predominance of mucus over the calves. With this form of development, enteropathogenic escherichiosis contributes to a significant loss of fluid and often leads to exsicosis.
• Enterotoxigenic types of pathogens cause escherichiosis, which in its current resembles cholera , due to the similarity of bacterial antigen (enterotoxin) to cholera. This form of infection is even more inherent in dehydration due to frequent liquid bowel movements and vomiting. To the fore, cramping pain occurs throughout the abdomen and frequent, sometimes almost continuous diarrhea , very quickly taking a watery character without fecal impurities. Later the pain syndrome subsides, the strengthened peristalsis is manifested by continuing diarrhea and rumbling in the intestine. In terms of severity, intestinal escherichiosis depends most heavily on the massive dehydration.
• The enteroinvasive group of strains differs from the other four in that it causes a pronounced inflammatory reaction of the intestinal mucosa, while escherichiosis proceeds according to the type of dysentery , since the antigen of this group of bacilli is very similar in structure to that of shigella - causative agents of bacterial dysentery. Pain is characterized by localization in the lower abdomen, stools frequent and with an admixture of mucus, later watery, with frequent false urges for defecation. Expressed intoxication (severe weakness with chills, muscle and headaches, a sense of weakness). When endoscopically examined in the colon, pronounced plethora is revealed, which spreads to the mucous and submucosal layers, small hemorrhages and superficial erosions, and less frequently ulcerative lesions. Because of the mucosal edema, the lumen of the intestine is narrowed in the distal part or the spasm spreads to the entire large intestine, the wall is compacted and very sensitive to instrumental manipulation. Cases of perforation of the large intestine with the development of peritonitis are described, but on the whole, Esherichiosis leads to such organ complications very rarely.
• The enterohemorrhagic group of Escherichia exerts a cytotoxic effect on the mucosa of the large intestine and endothelial lining of small vessels, which leads to the formation of bleeding erosions and is manifested by hemorrhagic diarrhea; in such a form, Escherichiosis resembles severe forms of dysentery.
• Entero-adhesive types of Escherichia coli cause such changes in the mucosa that lead, first of all, to the violation of the absorption processes, while in its course the escherichiosis becomes similar to salmonellosis . Entero-adhesive agents excite, to a much greater extent than other species, on the surface of the villi, completely envelop them, thus preventing wall digestion. As a result of this effect, intestinal contents are released in a practically unchanged form, depriving the body of not only nutrients, but also a considerable volume of liquid.
Escherichiosis can occur not only in the intestinal, but also in parakish form, since many species of escherichia are adapted to survive in other cavities, with the development of colpitis , pyelonephritis , meningitis , pneumonia, and in the generalization of the process - sepsis. Pneumonia and sepsis, escherichiosis is complicated in young children, similar cases in adults are found only against the background of sharply depressed immune defenses.
Escherichiosis in children
Escherichiosis in children has an acute onset with a rapid increase in symptoms. The incubation period usually does not exceed one day. Manifestations of infection will depend on the degree of severity (mild, moderate, severe), which, in turn, directly depends on the rate of dehydration.
Escherichiosis in mild form proceeds without obvious signs of intoxication, body temperature may not rise. Dyspeptic disorders also do not give the child any unpleasant sensations, but there may be aching pain in the abdomen, which is of a wave character. Stool up to five times a day, liquefied, can be foamy and with mucus impurities. The general condition as a whole remains satisfactory, but the kids get tired faster, sleep more, eat less. The symptomatology gradually ceases, after two or three days the child recovers.
The moderate-sized Escherichiosis causes much more anxiety for parents, as the child develops not only diarrhea, but also clear signs of toxic bacterial exposure manifested by high fever, headache and muscle pain, nausea, chills, weakness, sometimes vomiting. Pain in the abdominal cavity is often cramped, but may also be permanent. Escherichiosis of moderate severity provokes a quickening of the stool up to ten times a day and multiple false urges for defecation. Stools are liquid or foamy, but they retain a fecal color, can be with an admixture of mucus and green veins, while escherichiosis is very similar to a disinfection. Rapidly growing and rather turbulent symptoms reach a peak at the end of the first day, lasts one or two days and begins to gradually subside.
Escherichiosis in severe form is a rare phenomenon, usually observed in weakened children and manifested, first of all, by pronounced intoxication. High fever accompanied by lability and chills, frequent vomiting, severe weakness, refusal to eat. The urge to defecate can be up to 20 times a day and even more often, escherichiosis acquires a resemblance to cholera. Loss of fluid at the same time reaches a significant level - the child can lose up to 10% of the body weight in a day, which leads to the development of hypovolemia and exsicosis. Escherichiosis in severe form carries a significant threat to the life of the baby and requires treatment in the hospital.
Diagnosis of Escherichiosis
Escherichiosis has to be differentiated with so many infections caused by so-called diarrheal pathogens. Similar symptoms can be with any food poisoning, salmonellosis, bacterial dysentery, campylobacteriosis, cholera, gastroenterocolitis of viral origin.
The most reliable laboratory diagnosis of escherichiosis is the isolation of pathogenic E. coli from fecal or vomitic masses with further planting on a nutrient medium. If the escherichiosis proceeded in parakishechnoy or septic form, then for the sowing selected other biological media - blood in the generalized process, sputum in pneumonia, cerebrospinal fluid with the defeat of meningeal membranes, vaginal contents with colpitis and so on.
Laboratory diagnostics of escherichiosis includes serological methods, but false-positive results are often recorded because of the similarity of the structure of antigens, not only of different kinds of Escherichia coli themselves, which are part of the normal intestinal microflora, but also of many causative agents of related groups. Reliable immunological diagnostics is developed only for the enterohemorrhagic group of the causative agent causing escherichiosis, it is based on the detection of bacterial antigen in the stool masses of the patient.
Clinical laboratory tests allow us to detect signs of intoxication and inflammation, to which esherichiosis leads, but they are not specific and do not help differential diagnostics, but they give a detailed idea of the water-electrolyte composition of the blood and the degree of dehydration, which allows adjusting the therapy.
In general, Escherichiosis is diagnosed on the basis of a combination of manifestations of infection in a particular patient in combination with local-territorial epidemiological data and the dynamics of the development of symptoms.
Treatment of Escherichiosis
Escherichiosis, taking place in mild or moderate form, is quite acceptable to treat at home, with the main focus on preventing dehydration. The patient should consume more liquid than lose it with diarrhea, and since it is difficult to correctly determine the required amount, it is advisable to use Regidron, a drug that is able to keep water in tissues, preventing the development of exsicosis.
To eliminate the dyspeptic symptoms that accompany any type of esherichiasis, enzymes (Pansinorm, Mezim) and enterosorbents (Enterosgel, Polysorb, Enterodesis) are recommended for two to three days. With the same purpose, one of the intestinal antiseptics is prescribed (Intetriks, Enterol, Neointestopan). If the patient's condition is insignificant and the symptomatology of escherichiosis is limited to a low temperature, moderate diarrhea, mild weakness, then etiotropic (antibacterial) drugs should not be used, since they will further aggravate the imbalance of the intestinal flora, and eventually will have to treat dysbiosis .
Nutrition of the patient who has been diagnosed with escherichiosis needs to be organized in such a way as to exclude products that increase peristalsis and bloating, to this end, maximally limit the lungs (quickly digestible) carbohydrates, fatty foods. You can not use irritating hot sauces, marinades, carbonated drinks are contraindicated, as well as any canned products, whether domestic or industrial.
If escherichiosis occurs in severe form, then treatment should be conducted in an infectious inpatient to prevent infectious-toxic shock , exsicosis and other formidable complications, in such cases antibiotic therapy is indicated. It should be noted that Escherichiosis causes gram-negative bacteria, so the use of antibacterial agents of a wide range of effects is an unreasonable over-insurance, which has a harmful effect on the patient's own intestinal flora. The drugs of choice are those drugs whose effect is directed specifically on the gram-negative group of bacilli that cause escherichiosis, the best is Ko-trimoxazole, which belongs to sulfanilamides, and the fluoroquinolone series (Ciprofloxacin, Pefloxacin, Ofloxacin). Etiotropic medicines should always be combined with a correction of dysbiosis, for this purpose Bifidumbacterin-forte, Hilak-forte or other eubiotics are used.
Severe escherichiosis is always fraught with dehydration, so patients need rehydration therapy - intravenous administration of solutions of Acesol, Chloksol, and with significant intoxication phenomena, colloid preparations are indicated (Dextran).
In severe conditions, Escherichiosis significantly inhibits appetite, whereas the patient needs a full-fledged diet to support the body as a whole and its protective functions in particular. Frequent fractional feeding is shown, food should contain a sufficient amount of protein, amino acids, vitamins.
In the prognostic plan, Escherichiosis has a favorable outcome, with mild forms of recovery may occur spontaneously, with more severe, appropriate therapy is required. After treatment, long-term effects usually do not develop, in the clinical observation, people who have experienced escherichiosis do not need.
Prevention of Escherichiosis
In terms of prevention, Escherichiosis is nothing significant from other intestinal infections is not different. Individual preventive measures are reduced to developing and maintaining hygiene skills, inculcating them to children. Due attention should be paid to the cleanliness of housing, the rules of cooking and storing it, especially dairy and meat dishes, confectionery creams, cooked vegetables. One of the conditions for reducing the risk of infection is regular washing of the refrigerator with disinfectants.
Specific prevention for humans does not exist, serum against escherichiosis is developed only for farm animals.
The general preventive measures that prevent escherichiosis are reduced to the maintenance of sanitary norms in public institutions, including children's ones, special attention is paid to the condition of sources of drinking water and food points. Of great importance is the control of sewage and the quality of their decontamination.
One of the areas of prevention of escherichiosis is the isolation of the diseased before the complete cessation of the isolation of pathogenic bacilli, which is controlled by bacteriological research. For children's groups, the rules are even stricter-they are not allowed for those children who have contacted patients, admission is allowed only after a negative result of a laboratory test for escherichiosis.
Escherichiosis is included in the list of infections for which certain categories of workers are examined, primarily those associated with the food industry, the catering industry, food trade, which also contributes to reducing the risk of spreading the disease.
Escherichiosis occurs in all warm-blooded animals, including in domestic animals, with a prophylactic purpose for them developed a specific hyperimmune serum against escherichiosis, which allows reducing the incidence of disease not only in the animals themselves, but also in people in contact with them.
The escherichiosis transferred in the past does not leave permanent immunity after itself, moreover, even that unstable protection, which is still being developed, refers only to a certain group of pathogens, which does not eliminate the danger of being infected with pathogenic intestinal sticks of another group, so prevention of this type intestinal infection is very important.
? Esherichiosis - which doctor will help ? If there is or suspected of escherichiosis, you should immediately seek advice from such doctors as an infectious disease specialist, a gastroenterologist.