Yersiniosis is a pathology of infectious nature, which is provoked by the receipt in a susceptible organism of a specific pathogen provoking the development of a pathognomonic clinical picture that indicates the defeat of one or another organ.
Infectionists in the course of numerous laboratory studies managed to identify seven species of Yersinia, however, not all of them are pathologically dangerous for humans. The causative agent of yersiniosis is similar in morphological properties to the causative agents of plague and pseudotuberculosis.
The primary identification of the causative agent of intestinal yersiniosis was made in 1923 by American scientists. In view of the similarity of the pathomorphological features of this pathogen and the causative agent of pseudotuberculosis, the infectionists first had doubts about the legitimacy of the separation of these two pathologies. A more detailed study of the clinical and pathomorphological manifestations of intestinal yersiniosis and pseudotuberculosis made it possible to separate these two concepts, although pseudotuberculosis and yersiniosis are caused by a pathogen called iersinia.
In addition, similar antigenic agents for Yersinia are Salmonella, Shigella, Escherichia, Proteus, Cholera vibrios, as well as pathogens of brucellosis and tularemia.
The clinic of yersiniosis is so diverse that only on the basis of symptoms the doctor is extremely difficult to reliably verify the diagnosis. Intestinal yersiniosis, for example, can simulate the course of dysentery, acute hepatitis, appendicitis. Chronic iersiniosis is rare and differs from acute latent flow and the absence of specific laboratory markers.
Causes of yersiniosis
The causative agent of yersiniosis is nothing more than a Gram-negative mobile wand having rounded edges, and is not prone to spore formation. Taking into account the biochemical properties of the pathogen, five biovars were isolated, and according to the antigenic composition of Yersinia they are divided into 34 serovars, of which only seven are pathogenic.
Optimal favorable conditions for life and active growth of yersinia is the ambient temperature of 22-28 ° C, however, even at a temperature of 4 degrees Celsius these causative agents remain viable. Extremely negative on Yersinia is affected by exposure to ultraviolet rays, boiling and treatment with various disinfectants such as chloramine, alcohol.
Pseudotuberculosis and yersiniosis belong to zoonotic infections, which is why they have a similar pathogenesis of pathomorphological changes. For the development of yersiniosis, contact of a healthy person with an infected wild or domestic animal, birds, rodents or a person who has a yersiniosis clinic or asymptomatic carriage is necessary.
Pollution of household items, food and the environment, occurs as a result of the spread of biological secretions by infected animals or a sick person. Infection of food products, namely vegetables and fruits, which are consumed most often in raw form, occurs even at the time of their cultivation in the fields, where they are fertilized with manure collected from infected animals. In addition, the infection of vegetables is possible through rodent-infected vegetable stores.
In some situations, group intestinal yersiniosis can occur, resulting from the simultaneous use of the same contaminated food. Extremely rare is the aqueous mode of transmission of Yersinia, which is not excluded by infectionists. The main way of dissemination of intrahospital yersiniosis is contact-household.
The development of iersiniosis is more affected by urbanized populations that consume vegetables that are stored for a long time in vegetable stores where there is an increased risk of their infection with Yersinia. This infectious pathology takes place in different age categories, however, the severe course of iersiniosis develops, as a rule, in children.
Immune reactions occurring in the body with yersiniosis have not been studied enough, however, it is generally accepted that the absolute number of T-lymphocytes decreases with simultaneous increase in B-lymphocytes in the acute period of the clinical picture. A full immune response is accompanied by a gradual increase in the T-lymphocyte count and complete normalization in the convalescent period. Detection of a low level of T-lymphocytes in a patient is an unfavorable marker, since it signals the development of a protracted course of the disease. Chronic iersiniosis is always accompanied by a decrease in the number of T-suppressors. The development of specific antibodies in yersiniosis occurs in the second week, and their maximum concentration is observed by the end of the fourth week.
Symptoms and signs of yersiniosis
Like any other infectious pathology, iersiniosis has a period of incubation of the virus, averaging six days, during which the patient does not notice any changes in his own health.
The clinic of yersiniosis is very diverse in clinical symptoms, each of which can be attributed to this or that extensive syndrome. Thus, general toxic syndrome occurs in 100% of cases and is manifested by hectic fever, chills, intense headaches, general weakness, myalgia and arthralgia, that is, the clinical manifestations at this stage of yersiniosis are non-specific and can occur in most infectious diseases. The severe course of intoxication syndrome with iersiniosis is accompanied by the development of disorders of central nervous system structures, and the febrile period in this situation is marked by considerable intensity and duration.
Gastrointestinal form of yersiniosis is most often accompanied by a low intensity of intoxication syndrome with a pronounced intensity of dyspeptic syndrome in the form of nausea, vomiting, diarrhea, intense diffuse pain in the abdominal cavity.
To the rare clinical manifestations of yersiniosis is the exanthema of spotted-papular, small-to-large or coarse-sprouted type, appearing in the projection of the lower part of the upper and lower extremities. The appearance of the rash is most often accompanied by a burning sensation in the palms, and the leveling of the elements of the rash is accompanied by the development of peeling.
Some forms of iersiniosis are accompanied by the development of the clinic of arthropathic syndrome, which is manifested by the appearance of intense pains in small joints, edematous paraarticular soft tissues, limitation of motor function. Generalized yersiniosis in most cases is accompanied by the development of hepatolienal syndrome, the main manifestation of which is hepatosplenomegaly .
The most common form of iersiniosis is gastrointestinal, which is characterized by a combination of general toxication syndrome and dyspepsia. The pronounced intoxication syndrome in this form of the disease provokes the development of moderate poly-lymphadenopathy, which is manifested by an increase in various groups of lymph nodes, with complete absence of signs of their inflammation. The period of the acute period of the clinical picture of yersiniosis is on average two weeks.
The defeat of the intestine with yersiniosis proceeds according to the type of acute appendicitis or terminal ileitis, which are symptomatic similar to those caused by nonspecific flora.
Yersiniosis in children
The development of yersiniosis in children is always acute with the presence of a long period of incubation. Typical complaints of a patient with yersiniosis of a child in the initial period of the development of the disease are general weakness, adynamia, lethargy and severe chills. The second most frequent occurrence of the complaint is severe pain syndrome, localized in the head, muscles, large joints, and a sharp deterioration in appetite.
Most often, iersiniosis in children develops according to the gastrointestinal variant, the pathognomonic manifestations of which are intense spilled tenderness along the bowel, nausea and vomiting, which have nothing to do with food intake, bowel dysfunction in the direction of loosening the stool, and the development of constipation. Skin rash in yersiniosis is rare, and in a situation where it is observed, it extends mainly to the skin of the extremities and the face.
The complexity of early clinical diagnosis of yersiniosis in children is that in this category of patients, in addition to pathognomonic symptoms, a whole range of other clinical manifestations can be observed in the form of catarrhal phenomena such as dry cough and sore throat, runny nose, and conjunctivitis . The lymphoproliferative system responds to the introduction of iersinia into the child's body in that widespread lymphadenopathy and splenomegaly develops. To the rare symptoms of iersiniosis in children is the development of mechanical jaundice.
Thus, yersiniosis can develop in children in several clinical variants: gastroenterocolitis, icteric, exanthemic, arthralgic, septic, each of which differs not only in the prevalence of certain clinical manifestations, but also in the duration of the acute period.
Young children are more likely to develop gastrointestinal or generalized variants of yersiniosis, which are dangerous for the early development of the dehydration symptom complex, which in severe cases can lead to death. Treatment of yersiniosis in children should be performed only in a hospital infectious profile. Treatment of yersiniosis in children, even with mild course, should consist of a course of antibiotic therapy.
Diagnosis of yersiniosis
The diagnosis of "yersiniosis" only on the basis of clinical manifestations presents significant difficulties, since not in all situations the patient develops pathognomonic symptoms.
Special diagnostic tests include bacteriological analysis for yersiniosis, and the natural testicles of the patient, blood and, in rare cases, cerebrospinal fluid, are used as a material for the study.
In the stage of catarrhal phenomena, one can use the analysis on yersiniosis, by examining the mucus taken from the posterior wall of the pharynx and tonsils. In a situation where iersiniosis in the patient manifested as appendicitis and ileitis, the resected appendix and regional lymph nodes are used as a biological material for bacteriological research.
Sowing of sampled samples is carried out on special solid nutrient media with preliminary enrichment. In the laboratory confirmation of yersiniosis, it is mandatory to determine the serovar pathogen. As serological methods for the diagnosis of yersiniosis, RA and RNGA are used, and a diagnostic increase in antibody titer of 1: 200 is diagnostic.
The maximum confidence in the verification of the causative agent of yersiniosis is the analysis of stool and blood by the PCR method. For carrying out any bacteriological study with suspicion of yersiniosis in the patient, it is sufficient to study 3-5 g of feces and 50-100 ml of urine. The material, which is subject to further investigation, should be stored in conditions of low temperatures, and buffered, as well as 0.85% solutions of sodium chloride are used for the enrichment. Later, in the conditions of a specialized laboratory, the cultivation in a thermostat and sowing on nutrient media such as Endu agar with further cultivation under elevated temperatures are carried out. Identification of Yersinia is carried out on standard media of Giss.
Among the instrumental methods for the verification of yersiniosis, the most widely used ray methods of investigation are those that allow determining the pathomorphological changes in follicular ileitis in the form of the definition of numerous nodules of lymphoid hyperplasia in the projection of the ileum.
For non-specific laboratory diagnostic merekers yersiniosis should be considered leukocytosis and increased ESR in the blood test, as well as the detection of protein, leukocytes, erythrocytes, cylinders in the urine. The gastrointestinal form of yersiniosis is accompanied by the appearance of increased free bilirubin in the blood, as well as a moderate increase in ALT and AST activity.
Due to the fact that iersiniosis can occur atypically without the appearance of specific clinical symptoms, thereby simulating other diseases, both infectious and non-infectious nature, differential diagnostics is necessary. It is necessary to take into account not only the data of objective and instrumental examination, but also the data of the epidemiological anamnesis.
Treatment of yersiniosis
Treatment of patients suffering from iersiniosis should be combined and take into account not only the clinical symptom complex, but also the pathogenesis of the development of this infectious pathology. In the acute period of the disease, the primary task of the attending physician is to stop the manifestations of intoxication syndrome and to ensure the prevention of the development of complicated forms of yersiniosis. All patients, irrespective of the clinical variant of the course of yersiniosis, are hospitalized in a hospital of an infectious profile for a period of acute clinical manifestations.
Observance of a specific diet in this pathology is considered an optional therapeutic measure, but the use of an adequate scheme of antibacterial therapy is the key to successful treatment of the patient. Gastrointestinal form is the basis for prescribing antibacterial agents lasting about seven days, while other types of yersiniosis are subject to a longer course of antibiotic therapy. As preparations of choice for yersiniosis, preparations of the fluoroquinolone and cephalosporin series are used.
Gastrointestinal form of iersiniosis is accompanied by massive dehydration of the body, therefore the basis of pathogenetic treatment in this disease is the means used as rehydration and detoxification in oral and parenteral form. In the absence of a pronounced pharmacological benefit from the use of drug treatment to a patient with a gastrointestinal form of yersiniosis, surgical treatment is indicated, the volume of which is determined by the surgeon.
Etiotropic treatment in the generalized form implies parenteral administration of drugs with the aim of promptly arresting clinical manifestations, suspending pathological processes in the patient's body. In this situation, the antibiotic Pefloxacin was well recommended at a daily dose of 0.8 g, as well as Levomycetin succinate at a calculated dose of 10 mg per 1 kg of the patient's weight. Streptomycin sulfate is used as an additional antibiotic in severe generalized form of yersiniosis and its dose in this case is 1 g. In the case of complete absence of the effect of using antibacterial agents, which under normal conditions should occur on the second day after use, therapy should be supplemented with the appointment of a polyvalent yersiniosis bacteriophage 50 ml three times a day for five days.
Pathogenetic treatment of yersiniosis is carried out by prescribing restorative agents, detoxification and desensitizing treatment.
Prophylaxis of yersiniosis
In each state, there are and actively working bodies that are authorized to carry out sanitary and epidemiological surveillance of compliance with sanitary norms, which are aimed at the distribution of iersiniosis. Constantly, preventive measures should be taken to prevent the possibility of Yersinia contamination on foods that are subject to long-term storage, for example, vegetables.
Vegetables should be stored on special vegetable stores, equipped in such a way that rodents, which are the main vectors of Yersinia, are not allowed to enter them. All racks and shelves in vegetable stores are subject to mandatory regular disinfection followed by airing the room. The effectiveness of disinfecting measures is estimated only by sampling laboratory samples from the vegetable store surfaces, in which there should be no Yersinia even of the non-pathogenic serotype. Of no small importance is the maintenance of a certain microclimate in vegetable stores (air temperature 4 ° C and relative humidity up to 70%).
Patients who have undergone iersiniosis are subject to discharge from the hospital not only after the clinical manifestations of the disease have been eliminated, but also the complete normalization of the laboratory markers of yersiniosis, especially in the intestinal form. Bacterial carriers of Yersinia are subject to outpatient treatment. In order to prevent the spread of infection, bacterial carriers and patients with yersiniosis, persons working on food units are suspended from work for the period of drug treatment. Children who have suffered iersiniosis, after discharge from an infectious hospital, must be examined by the district pediatrician, since this pathology tends to develop chronicization of the process and the occurrence of relapses. Persons related to the decreed groups for iersiniosis are required to undergo a complete laboratory examination before discharge from the hospital, including not only biochemical indicators, but also stool analysis for the presence of iersinia.
? Iersiniosis - which doctor will help ? If there is or suspected development of yersiniosis, you should immediately seek advice from such doctors as an infectious disease specialist, a therapist.