[The modern characteristics of species identification of coagulase-positive bacteria of Staphylococcus genus.]

The development of molecular techniques of research in the end of XX century permitted to broaden nomenclature of species forming genus Staphylococcus that nowadays numbers 51 species and 27 sub-species. The pathogenic species of genus have a capacity to coagulate blood plasma of mammals forming group of coagulase-positive staphylococci including 7 species: S. aureus, S. delphini, S. intermedius, S. pseudintermedius, S. lutrae, S. schleiferi ssp. сoagulans, S hyicus. In clinical practice, S.aureus is considered as the most virulent among staphylococci. The cumulated data testifies increasing etiologic significance of other representatives of group of coagulase-positive staphylococci in human and animal infection pathology. The keen attention is needed to be paid to Staphylococcus intermedius of group (SIG), uniting three close kindred species: S. pseudintermedius, S. intermedius, S. delphini. Among them the most broadly prevailed are methicillin-resistant clones of S. pseudintermedius, capable to bring on in patient various pyoinflammatory diseases. The laboratory methods based on phenotype tests, provide no opportunity to differentiate coagulase-positive staphylococci because of significant similarity of phenotype characteristics in certain representatives of this group. Te comparative analysis was implemented concerning efficiency of various methods of species identification of coagulase-positive staphylococci: biochemical, molecular genetic (multi-primer polymerase chain reaction for identifying differences in gene structure of thermonuclease, analysis of polymorphism of lengths of restricting fragments of catalase gene and their sequencing), matrix-activated laser desorptional/ionizing time-of-flight mass-spectrometry (MALDI-ToF MS) with various modes of probe preparation. The analysis was applied to 117 isolates of representatives of SIG, separated from ill and healthy individuals of small domestic animals, clinical isolates form patients of hospitals. The multi-primer polymerase chain reaction permitted to identify 97% of isolates, analysis of polymorphism of lengths of restricting fragments of catalase gene - 100% of isolates that confirms efficiency of molecular genetic methods of analysis. The MALDI-ToF MS requires replenishment data base of mass-spectrometer and application of the mode of preliminary protein extraction of samples fo increasing efficiency of species identification of coagulase-positive staphylococci.

[SPECIFIC FEATURES OF ECOLOGY, PATHOGENIC PROPERTIES, AND ROLE OF THE STAPHYLOCOCCUS INTERMEDIUS GROUP MEMBERS IN ANIMAL AND HUMAN INFECTIOUS PATHOLOGY.]

The changes in the nomenclature of species in the genus Staphylococcus, including the most pathogenic cluster of the coagulase-positive staphylococci, are represented. Presently, besides S. aureus, this cluster consists of 6 species: S. intermedius, S. schleiferi ssp. coagulans, S. lutrae, S. hyicus, S. pseudintermedius, and S. delphini. A particular attention was paid to the Staphylococcus intermedius group (SIG), which includes three closely related coagulase-positive bacterial species: S. intermedius, S. pseudintermedius, and S. delphini. The hosts of SIG species are various mammals and birds, which live in a close contact with humans. The current knowledge about the virulence factors and pathogenicity for animals and humans are analyzed. The diffic6lties of the species identification, the features of ecology and epidemiology, antimicrobial resistance were reviewed. The biological features of S. pseudintermedius, which has the greatest similarity with S. aureus, are considered in the context of the properties of newly emerging pathogens.

[Micromechanical characteristics of restoration stomatological materials and human dental enamel and dentin]. / Mikromekhanicheskie kharakteristiki restavratsionnykh stomatologicheskikh materialov, émali i dentina zubov cheloveka.

Polished sections of human teeth and 11 Russian and foreign restoration materials (silver amalgam, cements, and polymer-based materials) were studied with an MTI-3M microhardness meter. Microhardness immediately under loaded diamond indentor of the device, elastic and plastic deformations were evaluated. Dental enamel is characterized by the greatest microhardness. Inorganic filler essentially (3-fold) increases the microhardness of polymer-based material. Microhardness of dental tissues and restoration materials notably decreased as the strength of indentor loading, i.e. the depth of its submerging in material, increased. Dental enamel is characterized by the most elastic deformation; dentin approximates the enamel by this parameter, as well as some restoration materials (prodigy, degufil-H, degufil-SC) when exposed to the saliva.