Maintenance of <I>Francisella tularensis</I> 15 RIEH and <I>Brucella abortus</I> 19 BA Strains in a Viable State by Means of Deep Freezing

Assessed are the methods for storage of microorganisms in a viable state under various technological conditions for a period of two years. Compared is the survivability of the test-strains of tularemia and brucellosis agents (exemplified by Francisella tularensis 15 RIEH and Brucella abortus 19 BA) when stored on the nutrient media at temperatures raging 0 °C up +8 °C and at -70 °C for over a year. Made has been an estimate of survivability of the vaccine strains stored at -70 °C within two years term. It is determined that optimum media for storing the stated above microorganisms with no changes in their morphological characteristics at -70 °C are sucrose-gelatin agar and Albimi broth with 10 % glycerin. Demonstrated is the fact that it is more efficient to conserve microorganisms stored in working collections by way of deep freezing

PLAGUE INFECTION SIMULATING IN CASE OF INOCULATION WITH AVIRULENT YERSINIA PESTIS STRAINS

Biological method of investigation is specified for the laboratory diagnostics of plague. Mastering of this method by the trainees within the frames of further vocational education is associated with the use of avirulent Yersinia pestis strains and vaccine Y. pestis strain EV line, which while providing safety does not allow for typical pathomorphological pattern on biomodels, as well as for isolation of microorganisms from internal organs. Objective of the study is to select avirulent Yersinia pestis strains and to conduct comparative analysis of the simulation techniques for plague on biomodels. Materials and methods. Utilized were Y. pestis strains. Virulence was evaluated both, in vitro (polymerase chain reaction) and in vivo (LD50 for white mice). Results and conclusions. Set forward have been avirulent Y. pestis strains, prospective in terms of mastering biological method of laboratory diagnostics of plague, and means of their application for simulating plague in biomodels. The designed approach allows for exercising biological methods of plague investigation to the fullest extent, enhancing biological safety of practical studies and reducing the time line for isolation and accumulation of pure bacterial culture

Results of Modeling Experiments in Designing Immuno-Enzyme Test-System for the Detection of Antibodies to <I>Yersinia pestis</I> F1 (ELISA-Ab-F1 <I>Yersinia pestis</I>)

Designed is immuno-enzyme test-system for the detection of antibodies to Yersinia pestis capsular antigen F1 – “ELISA-Ab-F1 Yersinia pestis”. On the model of laboratory mice it is demonstrated that this test-system is highly specific, its diagnostic titer being 1/320.Diagnostic value of the test-system is 83.3–88.9 % as revealed through investigations of sera and blood suspension samples, swabs of thoracic organs of animals, inoculated with live plague vaccine, strains of plague microbe, containing and deprived of pFra, as well as with heterologous bacteria

Molecular-Genetic and Phenotypic Peculiarities of Plague Agent Strains Isolated in Vietnam

Objective of the study is to investigate phenotypic and molecular-genetic features and perform whole genome sequencing of Y. pestis strains isolated in Vietnam. Materials and methods. Studied were phenotypic and genotypic peculiarities of 20 plague agent strains isolated in different prefectures of Vietnam. Carried out was SNP-analysis of the strains, sequenced were genomes of 8 Y. pestis strains. Results and conclusions. Based on the results of studies of differential biochemical characteristics all the investigated strains were attributed to oriental biovar of the main subspecies of plague agent, which was confirmed by the presence of marker indel mutation – deletion of 93 bps in glpD gene. Investigated was also the plasmid composition of the strains. On the basis of the conducted genome sequencing and SNP-analysis appurtenance of 19 out of 20 strains under examination was determined. They belong to 1.ORI2v phylogenetic branch, relative to the strains isolated in Yunnan Province, China, which points to their common origin. Identified was a marker SNP and developed the method of SNP-typing for 1.ORI2v strains from Vietnam

Diagnostic Efficiency of Adsorbed Anthrax Vegetative Fluorescent Immunoglobulins Demonstrated in the Medical Trials

Studied is the diagnostic efficiency (specific activity, sensitivity, specificity, reproducibility) of anthrax vegetative fluorescent immunoglobulins. Based on the data, received in medical trials, this preparation is recommended for registration as a product for medical application in the Russian Federation

Assessment of the New Set of Reagents AmpliSens <i>Brucella spp</i>.-FL with Hybridization-Fluorescent Detection

At CRIE, Moscow and RRAPI Microbe designed is the set of reagents for detection of Brucella spp. DNA in biological materials and cultures of microorganisms by means of PCR with hybridization-fluorescent registration of the results. This reagent set, AmpliSens ® Brrucella spp.-FL, is supplied in two modifications versus the mechanism of the results registration (FRT - real time and FEP - end-point). High diagnostic value of the reagent set is determined in medical trials at L.A. Tarasevich Institute. The set is registered as medical device

Comparative Analysis of Diagnostic Plague Antiphage Sera Received from Producers of Different Types

Manufacturing process of ovine hyperimmune sera against Pokrovskaya plague bacteriophage was worked out. Their stability in the process of storage was studied. Sera received were used as raw material to produce three experimental series of diagnostic plague antiphage ovine dry serum. Physicochemical properties, specific activity and specificity of the developed preparation were evaluated in comparison with similar commercial preparation produced from the equine serum. Similarity of all test parameters was revealed that enabled to recommend diagnostic plague antiphage ovine serum for application