[Monitoring for Neisseria meningitidis species using sequencing of variable fragments of surface proteins FetA and PorA genes].

AIM: To perform advanced antigenic characterization of meningococci belonging to serogroups A and B and circulating in Moscow according to modern nomenclature of Neisseria meningitidis strains. MATERIALS AND METHODS: Method of typing of "VR" fragment of FetA protein together with methods of genetic subtyping and multilocus sequence typing was used. RESULTS: Detailed information about studied strains was inputed in Internet database--http://pubmlst.org/neisseria/. Typing of serogroup B strains did not allow to define dominating variant of "VR, fragment of FetA protein which is in accordance with subtyping data obtained previously. Serogroup A strains were notable for less variability of "VR" fragment variants: 6 variants were detected. For the majority of serogroup A strains, it was possible to trace connection between belonging of the strain to particular genetic subgroup and its revealed antigenic profile. For strains from genetic subgroup VI, antigenic profile P1.5-2, 10; F1-5 detected in 14(18%) strains was typical, whereas antigenic profile P1.5-2, 10; F3-5 was typical for genetic subgroup X and was detected in 50 (63%) strains. Antigenic profile P1.5-2, 10-67; F3-5 was detected in 5 (6%) strains, and other 10 antigenic profiles were revealed in one strain each. CONCLUSION: Prevalence of strains with antigenic profile P1.5-2, 10; F3-5 is explained by change of predominant genetic subgroup from subgroup VI to subgroup X in Moscow population serogroup A meningococci observed after 2003.

[Genetic subgroups of Neisseria meningitidis serogroup A isolated from patients with disseminated forms of meningococcal infection in Moscow, 1969-2006].

Results of microbiological monitoring for serogroup A Neisseria meningitidis circulated in Moscow from 2002 to 2006 are presented. Using multilocus sequence-typing, molecular and epidemiologic characteristics of 32 cultures isolated from cerebro-spinal fluid of patients with generalized forms of meningococcal infection. Typed isolates belonged to 4 sequence types: CT-3349 (detected in 24 cultures), CT-2 (detected in 5 cultures), CT-75 (detected in 2 cultures), and CT-5803 (detected in 1 culture). All sequence types (except CT-5803) were detected in Moscow in previous years. Using Internet database (http://pubmlst.org/neisseria) they were genetically characterized and compared with data on serogroup A meningococci circulated in Moscow before 2002., meningococci belonging to epidemically dangerous genetic subgroup III were not detected between characterized strains. Typed isolates were distributed between subgroups VI and X, which are typical for the area under surveillance. Genetic changes in Moscow population of Neisseria meningitidis serogroup A, which manifested by shift of dominating genetic subgroup after 2002-2003, were analyzed.

[Use of a DNA-DNA hybridization method for studying Corynebacterium diphtheriae strains]. / Ispol'zovanie metoda DNK-DNK-gibridizatsii pri izuchenii shtammov Corynebacterium diphtheriae.

In addition to traditional tests, a battery of DNA probes was used to characterize 134 toxigenic and 125 nontoxigenic C.diphtheriae strains isolated in Russia in 1986-1989. 2.5% of nontoxigenic strains carried the determinants of both toxin subunits A and B, and 20% possessed at least a fragment of the gene determining toxin synthesis. Optimal conditions of hybridization technology were found. The method may be used as an alternative to traditional techniques in diagnostic studies and screenings.

[Bacteriophage P22 H5 transfection and infection of plasmid Salmonella strains]. / Transfektsiia i infektsiia bakteriofagom P22 H5 plazmidnykh shtammov sal'monell.

The results of the Ca2+-dependent transfection of the DNA of bacteriophage P22 H5 to constructed Salmonella typhimurium F'- and R+-strains LT2 WT-R and SA118 demonstrated that in these salmonellae the effectiveness of transfection depended on the specificity of the interrelation of plasmids with host strains. Plasmids RA1, R538-1 and RP1 stimulated the transfection of S. typhimurium strain LT2 WT-R, but suppressed the transfection ability of S. typhimurium strain SA118. At the same time the expression of the function of plasmids R446b and R64-11 did not depend on the host strain, as the former did not affect and the latter suppressed the release of transfectants in both Salmonella strains. The presence of plasmids R124, RA1, R64-11 and R724 in strain SA118, heat-sensitive in respect to the synthesis of cell-wall lipopolysaccharide, not only led to a decrease in the effectiveness of transfection; the effectiveness of the inoculation of bacteriophage P22 H5 was also suppressed 10(4) times in the presence of plasmid R124 and at least 10(10) times in the presence of 3 other plasmids. The development of resistance to S-specific bacteriophage P22 H5 was not linked with disturbances in the adsorption of this bacteriophage. Besides, the addition of CaCl2 into the medium completely removed the limitation of infection with bacteriophage P22 H5, determined by plasmid R124.

[Characteristics of Salmonella mutants competent for isolated nucleic acids]. / Kharakteristika mutantov sal'monell, kompetentnykh dlia izolirovannykh nukleinovykh kislot.

The method for the isolation of transfectable salmonellae by growing them in a liquid medium for a long time and selecting R-clones, subsequently tested in the Ca2+-dependent transfection of the DNA of bacteriophage P22 H5, was developed. The probability of obtaining transfectable clones varied between 18.3% and 48.3% in different Salmonella strains. Testing their sensitivity to specific bacteriophages used for the determination of structural distortions in the lipopolysaccharide layer of the cell wall made it possible to divide transfectable Salmonella clones into 3 phenotypical groups. The effectiveness of the formation of transfectants in the Ca2+-dependent transfection of the DNA of bacteriophage P22 H5 increased to 4.0 X 10(-8) - 8.0 X 10(-8) in the isolated R-clones of S. typhimurium strain SU453. In contrast to the initial strain, these R-clones were characterized not only by more effective transfection, but also by the possibility of plasmid transformation.

[Transfectable strains of Salmonella]. / Transfektabel'nye shtammy Sal'monell.

It the Ca2+-dependent system of an intact bacterial recipient the efficacy of DNA transfection of P22 H5 bacteriophage was determined in 48 strains of bacteria belonging to the Salmonella genus and in 5 Escherichia coli strains with known genetic characteristics and phenotypical properties. The sensitivity of the salmonella strains under study to R- and RS-specific bacteriophages, and also their capacity to ferment galactose were determined. Transfectable mutants of bacteria belongin to the Salmonella genus were referred to the Ra-type. The salmonella P22 H5 bacteriophage of the heterologous E. coli recipient isolated DNA transfection was demonstrated.

[Conditions for S. typhimurium transfection by isolated DNA from bacteriophage P22 H5]. / Usloviia transfitsirovaniia S. typhimurium izolirovannoi DNK bakteriofaga P22 H5

Transfection of spontaneous S. typhimurium LT2 WTR mutant, sensitive to bacteriophages FO, Ffm, 6SR, and resistant to bacteriophages P22 H5, C-21 and P1 vir, by DNA of P22 H5 bacteriophage in the presence of Ca2+ ions was demonstrated. The following were conditions of infection providing maximal and reproducible results: concentration of the recipient cells of 6--7x 109 cells/ml, DNA concentration of 30 microng/ml, CaC12 concentration of 0,25 M. The efficacy of transfection was 5 x 10-8.