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.
Method of typing of "VR" fragment of FetA protein together with methods of genetic subtyping and multilocus sequence typing was used.
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.
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.
The study was carried out to evaluate and compare analytical characteristics of reagents kits for identification of antigens of rotaviruses SD BIOLINE Rotavirus (Standard Diagnostics, Korea), RIDA Quick Rotavirus (R-biopharm AG, Germany), RotaStick One-Step Test (Novamed Ltd., Israel), QuickStripe Rotavirus (Savyon doagnostics Ltd., Israel), Rotavirus-antigen-IFA-BEST (Vector-Best, the Russian Federation), Rota-antigen (NPP AKVAPAST, the Russian Federation). The panel included 84 positive and 43 negative samples of rotaviruses group A according their content. The reagents kit "Amplisense OKI screen-FL" with confirming [P]G typing of positive samples was used for comparison. The comparison of analytical sensitivity of reagents kits was implemented on panel characterized by using technique of droplet digital polymerase chain-reaction. The indicators of diagnostic sensitivity and specificity of reagents kits amounted to 84.52% and 100%for SD BIOLINE Rotavirus and RIDA Quick Rotavirus, 71.43% and 100% for RotaStick One-Step Test, 75.00% and 100%for QuickStripe Rotavirus, 83.33% and 100% for Rotavirus-antigen-FA-BEST, 83.33% and 100%for Rota-antigen. The analytical sensitivity of immunochromatographic and immunoenzyme kits amounted to 5 x 106 GE/ml for [P]8G4 genotype of rotaviruses of group A. The reagents kits SD BIOLINE Rotavirus, RIDA Quick Rotavirus and Rotavirus-antigen-IFA-BESTdemonstrated matched high indicators of diagnostic sensitivity and specificity sufficient for etiological diagnostic of rotavirus infection at acute stage of disease. The analytical sensitivity of compared kits does not allow recommending them to apply in analysis of samples characterized by lower concentrations of rotaviruses (asymptomatic agents, objects of environment).
The study was carried out to establish values of parameters characterizing concentrations of pathogens (threshold cycle - Ct) correlating with acute phase of viral gastroenteritis. The groups of patients with sporadic and group morbidity of acute intestinal infections were examined. The reagents kits Amplience (The central research institute of epidemiology, Russia), in real-time format polymerase chain reaction were applied to detect Rotavirus grA, Norovirus GII, Astrovirus, Adenovirus grF, Shigella spp, EIEC, Salmonella spp, Campylobacter spp (thermophilic group).The analysis was applied to distribution of Ct depending on isolated and combined detection ofpathogens in clinical samples. The evaluation was implemented concerning effect on Ct values of both inhibitors of polymerase chain reaction contained in feces and application of various amplifiers such as Rotor-Gene Q (QIAGEN, Germany), CFX96 (Bio-Rad, USA), "DT-96" (DNA technology, Russia). The risks of cross contamination during carrying out of investigations are evaluated. The asymmetric or bi-modal character of distribution of Ct values related to cases of combined detection of several pathogens is established. The following indicators are established common for patients with mono-infections (Ct mean ± SD): Rotavirus grA (Ct 20.63 ± 6.35; n = 978), Norovirus GII Astrovirus (Ct 21.06 ± 6.54; n = 54), Adenovirus grF (Ct 8.42 ± 2.4; n = 42). The corresponding values for victims of infective episodes amounted to Norovirus GII (24.19 ± 5.29; n = 447) and Rotavirus grA (18.65 ± 4.16; n = 50). The recommendations are presented concerning practical interpretation of results of real-time polymerase chain reaction. The indirect characteristic of content of pathogens in samples of clinical material derived from real-time polymerase chain reaction provides important information about association of pathogen with acute phase of disease. The high informativeness of given type of investigations support possibility of its effective implementation not only doing etiologic diagnostic but also in case of isolation of pathogen in clinically healthy individuals and examination of objects of environment.