Diagnosis of dysentery

March 27, 2018 20:46 | Diagnostics
Bacteriological study is the leading and most common method in diagnosing dysentery. The presence of dysenteric bacteria in the feces gives 100% accuracy to clinical diagnosis. In a number of cases with erased forms, the data of bacteriological investigation are decisive. The bacteriological method is used not only to diagnose various forms of dysentery, but also to determine the cessation of bacterial release by convalescents, to identify sources of infection, to detect contamination of environmental objects, food, water.

The common laboratory diagnosis of dysentery, based on the identification of dysenteric microbes by biochemical and antigenic properties, does not always detect their presence. The different frequency of allocation of causative agents of dysentery depends to a large extent on the method of sampling and transfer of material for sowing, the day taken from the onset of the disease, the multiplicity of the study, the quality of the medium and the preservative, and the method of investigation. It is necessary to recognize the practice of taking feces for research during antibiotic therapy is incorrect, since the incidence of the pathogen is sharply reduced.

With the use of more rational methods of laboratory diagnosis, the number of bacteriological evidence of dysentery increases more and reaches 70-80%.

In order to increase the seeding of shigella, nutrient media with the addition of antibiotics are used. When tetracycline and levomycetin are added, the planting of shigella increases 2.3 times.

Seeding in pathological stools is significantly higher than with normal. The dependence of the seeding on the anatomical state of the mucous membrane and the distal segment of the sigmoid colon was established. Maximum sowing is observed in catarrhal-ulcer form. However, according to our data, out of 163 patients with rectomano-scans, 37.4% had bacterial excretion even with normal mucosa.

We observed 373 patients with bacteriologically confirmed dysentery. Zonne microbes were isolated in 64.7% of patients, Flexner sticks in 25.4%, Newcastle in 3.4%, Boyd - Novgorod III, 1.4% of children( Fig. 13).Some patients( 5.1%) entered the hospital already with a mixed infection, and then they alternately showed different types of microbes( mainly Sonne and Flexner).In 3 patients from one fecal sampling two types of dysenteric microbes were simultaneously sown - Flexner and Sonne( in 2 cases), Sonne and Newcastle( in 1 case).Subsequent crops gave seeding 1 type of dysenteric pathogen. Bacteriological inoculations were carried out 4-7 times a month. A total of 4,810 studies were carried out. Analysis of bacteriological studies showed that single sowing was observed in 23.7% of patients, while in Sonnet dysentery - in 26.5% of cases, in dysentery caused by the Flexner microbe - in 27.9% of cases. Repeated isolation of Zonne microbes from 2 or more times was observed in 73.5% of patients, Flexner microbes - in 72.1% of children. In 5,3% of patients there was a long-term secretion of microbes, from 9 to 16 times. According to our data, the duration of dysentery flow caused by Shigella Sonne and Flexner is not much different. Zoonne microbes were allocated repeatedly during 1-6 months in 72.0% of patients, on.for 7-12 months - in 23.2%, more than a year - in 4.8% of patients. Re-isolation of Flexner microbes for 1-6 months was observed in 85.7% of patients, from 7 to 12 months - in 6.1%, more than a year - in 8.2% of patients.

It should be noted that in the following years, after a change in the organization of hospitalization, with the exception of the possibility of reinfection, the creation of groups for convalescents, depending on the type of pathogen, such prolonged and persistent excretion of dysenteric microbes, according to our data, was noted much less frequently. However, in the 1970s, long-term isolation of shigella in children with a mildly erased form of dysentery, according to ME Sukhareva, etc., was noted for 7.7% of children from 6 months to 1 year and 3 months, according to E, V. Golyusova et al., In 8.8% of patients( during the year).

When studying the clinical course of dysentery with a change in the pathogen in 26 patients, we observed only 10 children with not pronounced symptoms of the disease, in 16 children the change in the form of the dysenteric pathogen was not accompanied by clinical symptoms of the disease. Bacteriological study of children, in whom there was a change in the type of pathogen, showed that the organism was quickly released from the pathogen. In 20 out of 26 children, a new type of dysenteric microbe( in 17 children the new species was the Flexner microbe) was sown from 1 to 3 times during 1-2 months, 12 of them only once. The study of the course of the dysentery process with mixed dysentery infection showed that the presence of 2, and sometimes 3 types of dysenteric pathogens does not cause a serious course of the disease.

For the determination of specific antigens in feces, the passive heme agglutination inhibition reaction( RTSGA) and the indirect heme agglutination reaction( RIGA) are used. LI Kalitseva et al. Indicate a higher sensitivity of the RTGS in comparison with the bacteriological method and the possibility of detecting the antigen at low concentrations of microbes. LP Zueva notes that of the 206 patients with bacterial dysentery, the diagnosis of dysentery was confirmed in 29,6% of cases, and with the help of the RNGA - in 40.3%.This reaction requires 4 hours instead of 3-4 days for the bacteriological method.

As an accelerated, specific and highly sensitive method for the diagnosis of dysentery, a coal agglomeration( ROA) reaction can be used. Simplicity of RUA implementation makes it promising for implementation in practice. Studies on approbation of RUA in the diagnosis of dysentery and coliinfection revealed high specificity and dependence on the duration of the disease.

In many cities of the country in recent years, the luminescent method of research using specific fluorescent sera has been mastered. The main advantage of this method is the ability to get an answer quickly, in 4-6 hours. In all typical strains of dysentery bacteria, when stained with homologous fluorescent sera, a bright green-yellow glow is observed, atypical strains glow weakly. When staining with heterologous fluorescent sera, there is no specific fluorescence. Positive results of the luminescent-serological method are observed 2 times more often than bacteriological. However, it is established that when Sh is indicated.flexneri and Sh.newcastle due to their serological links with other enterobacteria revealed nonspecific reactions. This method is successfully used to detect Sh.sonnei and especially with mass examinations.

For intraspecific typing, Sh.sonnei is used in recent years to define biotypes, phagotypes, colicinogenity and colicin susceptibility, while the epidemiological value of typing shigellas increases with their simultaneous use. Intraspecific typing of shigella is of great importance in the epidemiological process, it allows to determine the source of infection and the ways of its spread.

Typing of microbial cultures, including dysenteric microbes, is carried out using the microelectrophoresis method described by KI Markov. High specificity of the method of microelectrophoresis, based on the determination of the different mobility of bacterial cells in an electric field in the presence of immune sera, allows us to recommend it for differentiation of pathogens of intestinal infections, including dysenteric microbes.

A coprological examination has been applied for a long time. With macroscopic and microscopic examination of feces, mucus, leukocytes, erythrocytes, epithelial cells, the presence of pus, which is characteristic of the dysentery process, are found. However, the same coprocytogram can be found in intestinal diseases of another etiology. In addition, with light forms of dysentery, the coprogram gives very meager data. In a co-cytological study of 264 children with mild dysentery( 588 coprograms), only 17 of them( 6.4%) found single red blood cells and leukocytes in the number of 11 to 35 in the field of vision. Even in 3 children with pronounced pathomorphological changes in the mucous membrane of the rectum and sigmoid colon( hemorrhage, erosion), 3 and 4-fold coprocytoscopy revealed no pathological elements indicative of inflammation in the intestine.

For a more accurate study of the morphological changes in the intestinal mucosa in dysentery, a microscopic method of imprinting was proposed. The obtained imprints well reflected the morphological changes and phenomena of bacterial phagocytosis by neutrophilic leukocytes - micro- and macrophages. This reflects the processes of both degeneration and regeneration of the intestinal mucosa. The method is simple and can be used not only to diagnose dysentery, especially when differentiating bacteriocarriers from subclinical forms of dysentery, but can also serve as a criterion for the effectiveness of the treatment.

To obtain an accelerated tentative response, auxiliary methods are used, such as the reaction with the hapten and the reaction of the phage titer increase. The reaction with the hapten is based on the detection of specific polysaccharides of dysenteric microbes by the precipitation reaction. However, because of nonspecificity, this reaction is not suitable for diagnosis of dysentery. As for the reaction of increasing the phage titer( RNF), it should be noted that it is a specific diagnostic method. In addition, a positive result of the RNF is noted in later terms of the disease, when it is not possible to isolate dysenteric bacteria. However, despite the high specificity of RNF and the possibility of obtaining a response in 10-11 hours, the practical application of this reaction is limited due to the appearance and growth of phage-resistant strains of dysenteric microbes.

The diagnostic value of the intradermal test with the allergen Tsukverkalova as an additional test for the early diagnosis of dysentery, especially its light forms, both in adults and in children, is reported by most authors. According to OS Makhmudov and others, the intradermal test with dysenteric Zuverkalova was positive in acute dysentery in children in 83.7% of cases, with a prolonged dysentery in 70.0% and in chronic cases in 54.7% of cases, andWith age, the number of positive samples and their intensity increased. EN Belan successfully used Zuverkalov's test to identify hidden sources of infection in children's groups, and LO Sakvarelidze used it in epidemiological practice to identify sources of infection. At the same time, it should be noted that with high specificity of the intradermal test, it is not species-specific; a positive reaction is observed in patients with Sonne's dysentery using an allergen derived from Flexnik bacteria.

When identifying cultures, the keratoconjunctival test is widely used. The test culture is introduced into the conjunctival bag of guinea pig, and if after 18-20 hours( sometimes in 2-3 days) acute conjunctivitis and keratitis develops, the culture belongs to shigella, since other microbes of the intestinal group do not give this reaction.

The agglutination reaction( RA), the indirect hemagglutination reaction( RNGA), the complement fixation reaction( RSK), the bacteriolysis reaction, etc. are among the serological responses.

The authors' main disagreements regarding the use of the agglutination reaction in dysentery concern specificity, sensitivity in various forms of dysenteryand the height of the diagnostic titer. IV Ovsievskaya, SK Dzhaparidze, OS Makhmudov and others point out the specificity of the agglutination reaction. However, we can not agree with the authors who support the specific and even typical specificity of the agglutination reaction.

When studying the specific and typical specificity of the agglutination reaction during the study of 705 sera from 301 patients with dysentery with bacteriological confirmation, it was found that the average titer to the Flexner microbe was 1: 271, to the Sonne microbe - 1:53.In a study of 209 sera from 87 patients with flexner dysentery, the positive agglutination reaction was in 69.4% of cases. Of these, isolated from the Flexner culture - in 77.9% of cases with an average titer to the Flexner microbe 1: 362, in 19.3% of cases there were group reactions( simultaneously with the Flexner and Sonne culture) and only 2.8%with the microbe Sonne. Absolutely different relationships were observed in the dysentery of Sonne. In a study of 450 sera from 196 patients, a positive agglutination reaction was obtained in 60.2% of cases with an average titer to the Sonne 1:60 microbe, and to the Flexner microbe - 1: 214.The positive agglutination reaction was isolated in isolation from the Sonne culture in 13.3% of cases, while the response with the Flexner microbe was positive in 52.4% of cases, and simultaneously with 2 cultures - in 34.3% of cases.

Based on the results obtained, we came to the conclusion that under Flexner-dysentery the specific specificity of the agglutination reaction is expressed quite clearly, which can not be said for Sonne-dysentery. However, we did not identify the type-specificity of the agglutination reaction in flexner-dysentery. An extensive agglutination test with various Flexner rod serotypes in 37 children with dysentery caused by the Flexner microbe showed that in 34 of 36 positive reactions they were of a group nature, of which in 12 cases the group reaction was only with heterologous strains. Tigers with heterologous type were expressed more intensively than titers to homologous strains. The reason for wide cross-section serological reactions is the complexity of the antigenic structure of dysenteric microbes. The main antigen determines the specificity of the type, while the additional antigens are common to many types. According to our data, the height of the agglutination reaction titer varies depending on the type of pathogen and age of the patient. The highest titers are given by Flexner-dysentery. High titers( 1: 800-1: 1600) with the Flexner microbe were observed in 11.1% of cases, with the Sonne microbe - only in 0.2% of cases. Analysis of the data showed that for acute dysentery, agglutinins were detected in the first 7 days from the onset of the disease, reaching a maximum in Flexner-dysentery by the 9th-10th day and Sonne-dysentery by the 20th-24th day.

With prolonged dysentery( in 61 children 136 studies were conducted), the agglutination test was positive in 65.4% of cases. In the study of 477 sera from 195 patients with chronic dysentery in 63.7% of cases, agglutinins were detected in the diagnostic titer. There was no significant difference in the agglutination reaction and its intensity depending on the nature of the course of the dysentery process, however, a higher titer of agglutinins was noted in the recurring course of chronic dysentery. The conducted studies of immunological reactivity of children showed that the baby's organism of the first months of life does not have sufficient ability to respond immunological response to the introduction of dysentery antigen. This ability becomes quite pronounced after a year of life. The agglutination reaction was positive in 1/4 patients under the age of one year and with lower titers( mean titer was 1:11), at the age after 1 year - in 3/4 patients and with higher titres( in children from 1 year to 2 yearsyears the average titer was 1: 320).

The study of the agglutination reaction before and after treatment with various antibiotics, a dysentery vaccine and a combined method was conducted by us in 230 children. Summarizing the obtained data, we came to the conclusion that after the use of the dysentery vaccine and the combined method of treating children with chronic dysentery, the average titer of agglutinins increases by a factor of 1.5.We also did not notice the pronounced inhibitory effect of antibiotic therapy on the agglutination reaction.

When we examined 256 children admitted with a diagnosis of bacilli-carrier of dysentery, a positive agglutination reaction was in 173 people( 67.6%), which helped establish a dysentery process.

Summarizing the data presented in this section, it can be noted that the agglutination reaction in combination with other methods can be used in the laboratory diagnosis of dysentery. However, due to the lack of specific and typical specificity and the presence of group reactions, it is impossible to determine the type and type of the causative agent of dysentery by the agglutination reaction.

The reaction of indirect hemagglutination( RNGA), which was proposed in 1954 by Noether and Walcker with erythrocyte diagnosticum, is highly specific and more sensitive than Vidal's reaction.

The diagnostic value of the RNGA is currently not in doubt. With the use of RNGA in patients with bacteriologically confirmed dysentery, an increase in antibody titer of 1: 100-1: 800 and above was noted in 92.5-100% of cases. Higher titres compared with Vidal's reaction and, most importantly, species specificity, attach special value to this reaction, but in young children the percentage of positive results is rather low.

One can not ignore a certain diagnostic value and an immunological method such as opsonophagocytic reaction, which in the dynamics of the disease, especially in combination with other methods, is helpful in establishing the etiology of intestinal disorder. Proponents of high specificity of the phagocytic reaction in dysentery are KA Telkova;I. V. Korshun;OS Mahmudov and others.

We opsonophagocytic reaction was studied in 123 children with dysentery, as well as in 27 children with pneumonia and other diseases that had no gastrointestinal disturbances and no history of previous dysentery.

It was found that if in 24 children( out of 27) of the control group the percentage of phagocytes was low and ranged from 4 to 20 with a low phagocytic index from 0.12 to 0.96, then in 122( 99.2%) patients with dysenteryin all children, dysentery was confirmed bacteriologically), the percentage of phagocytes ranged from 26 to 80 with a phagocytic index from 1.0 to 4.5, of them in 108 children with medium and high rates of phagocyte count( 51-80), in 86 patients with a phagocytic indexhigher than 2.0.We have not identified the specific specificity of the opsonophagocytic reaction. The phagocytic activity of leukocytes at all indices, including medium and high, was revealed not only to the homologous, but also to the heterologous strain of the dysentery culture. According to our data, with acute dysentery, a phagocytic index with high and medium indices was already observed from the 6th day of the disease, and then by the 13th day these indicators decreased, approaching normal and even low.

In the study of the phagocytic index in patients with protracted dysentery, mean and high rates of phagocyte count were in 25 of 29 patients with the Sonne microbe and in 23 patients with the Flexner microbe. At the same time, it was found that phagocytosis of medium intensity was noted during 2.5 months of the disease. With recovery( by the 3rd month), the phagocytic index decreased to moderate( normal) intensity. A survey of 68 patients with chronic dysentery revealed that the phagocytic index in the middle and high indices was in 72.0% of patients to the Sonne microbe and in 76.5% to the Flexner microbe. Moderate indicators were recorded in 28.0-22.0% of patients and low( only for the Flexner microbe) in 1.5% of patients. The curve of the phagocytic index in chronic dysentery, depending on the term of the disease, has a wavy character within the average intensity of phagocytosis. Comparison of the average indices of phagocytosis depending on the nature of the course of chronic dysentery showed that phagocytic activity in recurrent and asymptomatic forms of the disease is higher than in the case of continuous dysentery.

In order to compare different immunological indices in 120 children with dysentery, we simultaneously studied the agglutination reaction and the opsonophagocytic test. Analysis of the obtained data showed that in children of all age groups up to 5 years, opsonophagocytic reaction in acute, prolonged and chronic dysentery is positive 2-3.5 times more often than the agglutination reaction. This allows us to conclude that the phagocytic index can be used as an additional method that confirms the diagnosis of dysentery.

In recent years, a new serological method for the diagnosis of dysentery is used - the method of immunofluorescence in indirect modification to detect specific antibodies to dysenteric microbes in the sera of patients. A titer of 1:40 and higher is considered diagnostic. When examining children with dysentery, LE Shikhina et al. Established a positive reaction of immunofluorescence in 69.2% of cases with a maximum level of fluorescent antibodies within the 1:60 range.

As additional serological tests for the diagnosis and study of pathogenesis, mention should be made of the reaction of immune bacteriolysis, which is based on the lysis of microbes by immune serum in the presence of complement. The reaction is specific. At the end of the first week of the disease and later, the bacteriolysin titres in the blood of patients with bacteriologically confirmed dysentery were 1: 320-1: 640, while in the serum of healthy bacteriolysins are usually absent or in individual cases the titer is 1: 10-1: 40.

Currently, as an auxiliary test for the diagnosis of dysentery, the indicator of damage to blood neutrophils( DPN) is used, which allows to reveal the formation of specific sensitization in dysentery. The DPN test is more sensitive than skin tests. The method is rather simple( only 0.16 ml of blood taken from the finger is needed), it is harmless, since it is produced in vitro( using dysentery), the results of the reaction can be obtained after 4-5 hours. In children with acute dysentery, mean and high values ​​of PPN were observed in 64 + 3.7% of cases.

Recto-manoscopy as a valuable additional method of diagnosing bacillary dysentery has been known for half a century, but in children's practice it has been used in recent decades.

We subjected to a sigmoidoscopy examination, 153 children, with mild and worn out forms of dysentery at the age of 1 to 6 years( 126 children under 3 years old) and 10 children with dysentery bacteriocarrier. A total of 322 sigmoidoscopy was done before treatment and before discharge. Morphological changes during a sigmoidoscopy study were found in 66.7% of patients with dysentery, mainly in the form of catarrhal proctosigmoiditis( in 71.6% of patients).With this form of lesion, the mucosa of the rectus and the sigmoid colon was hyperemic, its looseness and vulnerability was noted, and there was a cloudy mucus in the form of lumps on the intestinal wall. Catarrh-hemorrhagic inflammation of the mucosa was found in 8.8% of patients, catarrhal-erosive process - in 13.7% of children. In all children, single small surface erosions were observed at a depth of 7-17 cm at 5.9% of patients. Atrophic changes were detected in which the mucosa of the rectus and sigmoid colon was pale gray in some areas, the folds were smoothed, the mucosal elasticitywas largely lost. We have established that pathological changes in the intestinal mucosa in dysentery in children from 1 year to 2 years are not less common than in older children. The study of the morphological state of the mucous membrane of the rectus and sigmoid colon, depending on the course of the dysentery process, showed that pathological changes were more often observed in acute dysentery, despite the erosion of the clinical picture in these patients. The most pronounced changes in acute dysentery were found in the first 2 weeks of the disease. With the course of the disease, inflammatory changes in the mucosa of the distal part of the large intestine decreased, but nevertheless, 10 children who were examined at a later date of the disease( later than the 20th day) showed quite pronounced changes in the mucosa in the form of catarrhal proctosigmoiditis. With prolonged and chronic dysentery, pathological changes in the mucosa of the distal part of the large intestine were detected in 63.6% of patients( 77 of 121).Significant changes in the mucosa in the form of catarrhal-erosive and catarrhal-hemorrhagic proctitis and proctosigmoiditis were observed mainly in patients with a recurrent course of chronic dysentery. Catarrhal changes prevailed in children with continuous course.

We did not notice a marked relationship between the normalization of the distal intestinal mucosa and the treatment method. In all cases, the recovery of the mucosa significantly lagged behind the clinical recovery.

The study of the correspondence of the character of the stool to the sigmoidoscopic picture showed that 21.6% of patients did not observe this correspondence. Of the 115 patients with abnormal stool, 91 males had changed mucosa( in 24 patients, the mucosa was normal).Out of 48 people with a formalized stool, pathological changes from the distal intestinal mucosa were found in 11 patients. Our analysis of sigmoidoscopy studies did not show any differences in pathomorphological changes, depending on the type of pathogen.

Recto-manoscopy is a valuable additional method when distinguishing a healthy dysentery bacteriocarrier from a disease with mild, worn out forms of dysentery. Carried out skillfully and carefully, sigmoidoscopy in children does not give any complications and is easily transferred. However, in pediatric practice, sigmoidoscopy is used in a limited way. It can be used for children older than a year and in later periods of the disease, provided that the doctor has extensive experience in assessing visible changes.

Aspiration biopsy of the distal colon was only applied in recent years. A biopsy is performed during a sigmoidoscopy with the help of special devices. In vivo morphological study is carried out in both acute dysentery and chronic dysentery. This method is especially valuable for revealing the erased, light forms of dysentery. According to AP Tarasova, GI Osinova, who performed aspiration biopsy in children with acute dysentery, catarrhal-hemorrhagic forms of inflammation with mild infiltration are observed. During the period of clinical recovery, there was no complete normalization of the mucosa.

Women's magazine www. BlackPantera.en: Ivan Korshun