Patterns determining the dynamics of the epidemic process in Sonne dysentery and its relation to the type of causative agent]

The results of studying the dynamics of the epidemic process of dysentery, based on the data from 3 districts of Moscow, are presented. The study revealed the periodicity of 3 years in the course of the epidemic process of dysentery, occurring against the background of a considerable predominance of Sh. sonnei, biochemical type 2. The use of the cohort method for analyzing the age structure of dysentery cases showed the possibility of using this method to find out to what extent the epidemic process repeatedly affected the same groups of population.     

Relation of the epidemiological characteristics of dysentery to the biological properties of the causative agents

The main forms of the epidemic manifestation of dysentery induced by different causative agents in 1975-1980 were revealed. During these years the cases of dysentery induced by Shigella sonnei, biovar II, were found to prevail (82.0-90.1%) both at the periods between epidemics and at the periods of the seasonal rise of morbidity. The experimental infection of white mice by intraperitoneal inoculation revealed no relationship between the seasonal rise of morbidity in dysentery and the virulence of its causative agents.     

Serological method of detecting the antigens of the causative agent of Sonne dysentery in lysates of the fecal inoculates from patients]

Serological method of detection of Sh. sonnei antigens in the lysates of the patients, fecal cultures is suggested and approved. In the majority of cases of the results of bacteriological and serological methods of study of the feces coincided. Data confirming the specificity of the antibody neutralization test (ANT) in Sonne dysentery are presented. In connection with detection of the screening action of the Vi-antigen of typhoid bacilli there were elaborated additional methods for verifying the specificity of the ANT results. It is recommended to keep agar plates after selection of suspicious colonies during the bacteriological test; the lysate of the microbial crop should be additionally subjected to the ANT, this considerably increasing the percentage of laboratory confirmations of dysentery caused by Sh. sonnei.     

Trends in the spread of Boyd 4 dysentery and the characteristics of its clinical picture and of the biology of its causative agent

The data on the proportion of S. boydii 4 in the general structure of the causative agents of dysentery, as well as in the intraspecific structure of S. boydii, in some areas of the USSR in 1977-1981 are presented. S. boydii strains 4, circulating in one of the areas where their proportion considerably increased in 1980-1981, corresponded to their taxonomic position in their biological properties, while forming a single biochemical variant according to the character of the fermentation of sorbitol, maltose and arabinose. These strains gave identical antibiotic sensitivity charts and showed pronounced multiple resistance to antibiotics, including ampicillin. The clinical features of the diseases caused by S. boydii 4 consisted in the sharply defined prodromal period and pronounced systemic toxicosis at the initial period of the disease, accompanied by the syndrome of moderate colitis localized mainly on the right side.     

Unusual serovar of the causative agent of Flexner's dysentery. I. Its distribution and biochemical properties

The data on the circulation of some S. flexneri strains in the USSR are presented. The antigenic structure of these strains (type antigen 4 and group antigens 7, 8) is not characteristic of known serological subvariants 4a, 4b or var. X. The time course of changes in their spreading on certain base territories controlled by the All-Union Shigellosis Center in 1980-1983 is shown. The biochemical characteristics of S. flexneri strains IV:7,8 under study, isolated in the USSR and abroad (Czechoslovakia, London) from humans, from a monkey and from the environment, are given. Similarities in the biochemical reactions of these strains with respect to indole, rhamnose, saccharose, maltose, arabinose and raffinose have been revealed. The strains isolated in the USSR have shown differences in the spectra of their resistance to antibiotics, depending on their territorial origin.     

The world-wide pandemic and drug resistance of the causative agent of Grigor'ev-Shiga dysentery

One of the factors facilitating the global pandemic of Grigor'ev-Shiga dysentery is considered in detail. All Shigella dysenteriae 1 strains, irrespective of the geographical zone of their spread, showed medicinal resistance. As pandemic developed, the spectrum of medicinal resistance constantly increased in all hyperendemic foci. The presence of pronounced relationships between the strains circulating in each of three hyperendemic foci and the strains circulating in different hyperendemic foci could be observed. The necessity of paying greater attention to this dangerous infectious disease, and especially to the problems related to the medicinal resistance of its causative agents, is emphasized.     

Adenylate cyclase of the causative agent of plague: its purification and properties

Three forms of adenylate cyclase have been detected in Y. pestis: membrane-bound, cytoplasmic and extracellular. Extracellular adenylate cyclase has been purified so as to achieve a homogeneous state, and some of its physicochemical parameters have been investigated. In the process of purification the initial preparation of this enzyme has been subjected to heating at 100 degrees C for 15 minutes, fractionation with ammonium sulfate, and gel filtration on Sephadex G-100. The homogeneity of adenylate cyclase has been confirmed by electrophoresis in 7.5% polyacrylamide gel and precipitation by the plague agglutinating serum. The enzyme has been found to have a molecular weight of 30,000 daltons and to show the optimum activity at pH 7.0-7.2 and at a temperature between 37 and 40 degrees C. Monospecific rabbit serum to the homogeneous preparation of adenylate cyclase has been obtained.     

Duration of bacterial discharge in Sonne dysentery]

The authors report on the results of their observations during 3 epidemic outbreaks. Despite different intervals at which the bacteriological examinations were carried out comparable data were obtained: during 2 outbreaks when no chemotherapeutic agents were used in 78.0 and 79.9% of children shigella discharge ceased in 4 weeks. Daily bacteriological examinations carried out in the course of the 3rd outbreak showed the maximal intermittent bacterial discharge for up to 79 days in individual cases.