[DETERMINATION OF PHYLOGENETIC RELATIONSHIP OF YERSINIA PESTIS STRAINS FROM NATURAL PLAGUE FOCI OF THE CAUCASUS BY MULTI-LO- CUS VNTR-ANALYSIS].

AIM: Determination of the degree of phylogenetic relationship of Yersinia pestis strains iso- lated from the territories of natural foci of plague from the Caucasus using VNTR-typing by 25 loci (MLVA25). MATERIALS AND METHODS: 26 strains of Y pestis from Russian natural foci of the Caucasus were used in the study. 25 loci of tandem repeats in Y pestis genome by Le Fleche scheme were used for execution of multi-locus VNTR-analysis. Deciphering of nucleotide sequences was carried out in automatic sequencer ABI 3130 Genetic Analyser. Analysis of confinement of clusters to certain territories, objects and time of isolation of strains was carried out. using Arc GIS 10.1 program. RESULTS: Groups of MLVA25-types of various levels of discrimination were formed: clusters, groups and subgroups. Clusters were formed by strains ofvarious taxonomic membership: main and subspecies of Y pestis. Subgroups reflect membership of strains in certain foci, and MLVA25-types - the degree of genetic relationship. CONCLUSION: Genetic <> of plague causative agents obtained using MLVA25-types circulating in various natural-focal territories allow to solve problems ofboth theoretical and practical character: from interpretation of microevolution processes to the search of the source of infection and ways of its spread during possible epidemic complications.

[FEATURES OF MASS-SPECTROMETRIC PROTEIN PROFILES OF STRAINS OF BRUCELLOSIS CAUSATIVE AGENT DURING PREPARATION OF CULTURE ON VARIOUS NUTRIENT MEDIA].

AIM: Carry out comparative analysis using time-of-flight mass-spectrometry with matrix laser desorption/ionization (MALDI-TOF MS) of protein profiles of brucellosis causative agents (Brucella melitensis Rev-1 and Brucella abortus 19BA), cultivated in various nutrient media: Albimi agar, brucellagar and erythrit-agar. MATERIALS AND METHODS: Vaccine,strains: Brucella melitensis Rev-1 and Brucella abortus 19BA. Protein profiling in linear mode on Microflex "Bruker Daltonics" MALDI-TOF mass-spectrometer. RESULTS: A number of characteristic features of brucella mass-spectra was detected: in particular, preservation of the total qualitative composition of protein profiles of cultures and significant differences in the intensity of separate peaks depending on the nutrient medium used. CONCLUSION: Based on the analysis of the data obtained, use of Albimi agar as the nutrient medium for preparation of brucella culture samples for mass-spectrometric analysis was shown to be optimal.

[The duration of preservation of plague pathogen strains with a different plasmid kit from a Central Caucasian high-altitude natural focus in the organism of citellophilus tesquorum fleas and the possibility of their transmission to laboratory animals].

Two plasmid variants of the main subspecies of the plague microbe circulate in a Central Caucasian high-altitude natural focus of plague. The strains of one plasmid variant fully correspond to the main subspecies of the plague pathogen in their characteristics. Those of the other are auxotrophic for proline, weakly virulent to one or both species of laboratory animals. The mountain subspecies of Citellophilus tesquorum fleas excretes the greatest quantity of plague microbe strains so the investigation of whether unblocked fleas can transmit the plague microbe is of interest.

[Relations of the causative agents of plague and listeriosis during their simultaneous stay in the flea Citellophilus tesquorum at different environmental temperatures].

Experiments were carried out to determine the persistence of a plague microbe with varying praline labeling (isolated in the Central Caucasian mountain focus of plague in the fleas Citellophilus tesquorum of a mountain subspecies) in the contamination of the mixed culture of the plague microbe and Listeria. Inoculation of fleas with a suspension of a plague microbe and Listeriae demonstrates the manifest signs of antagonism between both species of microorganisms. This is evidenced by the reductions in the time of cultivation and in the number ofthese bacterial species in the experimental group fleas co-infected with Yersinia pestis and Listeria monocytogenes as compared with the control fleas (infected with monocultures of the causative agents of plague and listeriosis). Inhibition of one bacterial population by another is pronounced temperature-dependent: + 4 degrees C is preferable for a proline-auxotrophic plague agent strain and environmental temperature elevation up to 18-20 degrees C ensures the preponderance of Listeria in C. tesquorum. Co-infection of fleas with plague bacteria and Listeria (which cannot be excluded in co-infections in mountain sousliks under natural conditions) may predict the suppressed vector activity of fleas and hence the limited circulation of the causative agent of plague by the rodent-flea-rodent scheme in the Central Caucasian mountain natural focus at an environmental temperature of + 18-20 degrees C.

[Current state of epidemiologic surveillance of natural foci of plague of North Caucasus]. / Sovremennoe sostoianie épidemiologicheskogo nadzora v prirodnykh ochagakh chumy Severnogo Kavkaza.

Information on the epizootic situation in plague in the natural foci of North Caucasus and on the influence of a number of anthropogenic and natural factors on this situation is presented. The data given in this work indicate that under the conditions of the anthropogenic transformation of landscapes the character of the epizootic manifestations of plague is changed and new factors, capable of aggravating epidemiological situation, appear. In addition, some other factors must be considered, such as the insufficient financing of reliable field surveys at present, the impossibility of making reliable epizootological studies due to causes of the social character (armed conflicts), thus making it impossible to evaluate, with a sufficient degree of reliability, the real epizootic state of a number of territories and, therefore, the risk of human infection. In this connection the necessity to carefully plan prophylactic measures and measures aimed at the localization and liquidation of the probable foci of infection arises.

[Detection of plague microbe in the fleas by polymerase chain reaction by using magnetic immunosorbents]. / Obnaruzhenie chumnogo mikroba v blokhakh metodom polimeraznoi tsepnoi reaktsii s ispol'zovaniem magnoimmunosorbentov.

The polymerase chain reaction (PCR) with and without pre-treatment of the samples of the fleas Citellophilus tesquorum with magnoimmunosorbents was used to detect the plague microbe in the samples containing 142, 168, 193 or more bacterial cells. PCR analysis reduced the time of tests of ectoparasites for plague to 6 hours. The use of a combination of PCR and magnoimmunosorbent simplified the most time-consuming and longest stage of isolation of plague microbial DNA from the suspensions of the fleas, which allows the time of a test to be reduced to 3 hours. The administration of an affine sorbent having magnetic properties during treatment of samples with plague-infected exoparasites for PCR analysis makes it possible to have a specific concentration of Yersinia pestis and to prevent the inhibitory effect of flea tissues on the polymerase chain reaction, to use the boiling method for isolating microbial DNA and for disinfecting the material to be tested.