An Esсherichia coli 42cpa-c strain synthesizing C-terminal fragment of Clostridium perfringens alpha-toxin was engineered. The strain is distinguished by productive capacity 1.2 mg of target protein per 1 L of cultural liquid. The protein contains octahistidine peptide at C-end of the molecule, enabling to carry out its one-stage purification by metal-affine chromatography on Ni2+-NTA resin. The resulting CPA-C protein preparation is potentially suitable for formulation of the derived vaccine.
Background. The monitoring of enteric viruses in wastewater is a new epidemiological approach allowing to detect the intensity of their circulation in humans. The aim of the study is to conduct and analyze parallel monitoring studies of wastewater and biological material from patients with acute viral intestinal infections (AEI) selected from different regions of the Republic of Belarus in terms of their actual pathogens. Material and methods. 403 samples of wastewater and 381 samples of feces from patients with AEI, collected in different regions of Belarus, were examined by real-time PCR. Results. In patients with AEI, rotaviruses A (20,4%) and noroviruses of the genogroup 2 (10,2%) were most often detected, while adenoviruses F (2,2%), enteroviruses (0,8%) and noroviruses 1 (0,3%) were found quite rarely. Adenoviruses F (25,9%), rotaviruses A (18,4%) and enteroviruses (13,4%) dominated in wastewater samples while noroviruses 2 (6,8%) and noroviruses 1 were detected much less frequently (1,5%). Certain differences were revealed in the percentage of viral AСI pathogens present in patients and those found in wastewater, that indicates active hidden circulation of some of them (adenoviruses F and enteroviruses). SARS-CoV-2 coronavirus was detected in one of the wastewater samples. The conducted sequencing and bioinformatic analysis of its nucleotide sequence showed 100% similarity with the sequences of isolates identifed in patients with COVID-19.Conclusions. The obtained data indicate the potential of the studies based on monitoring of intestinal viruses in wastewater in order to increase the effectiveness of epidemiological surveillance of known AEI pathogens circulation and to identify new and emerging ones.
Background. Individual cases of viral hepatitis E are recorded in the Republic of Belarus annually indicating the need for the pathogen monitoring at both the population and reservoir levels. Objective. To consolidate the monitoring data on hepatitis E virus over the period of 2018 - 2021, as well as to work out an effective algorithm for its laboratory screening. Material and methods. As part of the study, 345 samples were analyzed, including 227 human biological samples, 37 samples of biological materials of domestic pigs, 22 samples of food and 59 samples of waste water. Results. According to the results of serum diagnostics, in the group of kidney recipients (n = 29), the detection rate of IgM and IgG to hepatitis E virus was 6.9% [0.85%; 23.03%] and 17.2% [7.13%; 35, 02%] respectively; in the group of patients with pregnancy pathology (n = 44) - 6.8% [1.68%; 18.89%] and 11.4% [4.5%; 24.43%] respectively. In patients with acute hepatitis of unknown etiology (n = 26), antiviral IgM was not detected, while the frequency of antiviral IgG detection reached 7.7% [1.02%; 25.26]. In control group (blood donors, n = 53) IgM and IgG were detected in 1.9% [0.6%; 10.88%] and 5.7% [1.35%; 15.97] of those examined respectively. Hepatitis E virus RNA was detected in 8 human biological samples (3.8%) from kidney recipients. The identified hepatitis E viruses were represented by genotype GIII and belonged to a previously unidentified subgenotype (GIIIa - GIIIi). In the studied samples of biological material from pigs, as well as in samples of food and waste water, hepatitis E virus RNA was not detected. Conclusions. An algorithm for hepatitis E virus laboratory screening has been developed and tested. Its section concerning the diagnosis of viral hepatitis E is set out in the Instructions for use "Algorithm for laboratory diagnosis of viral hepatitis E" (No. 148-1220 from January 28, 2021).
Noroviruses are widespread causative agents of acute gastroenteritis (AGE). In recent years, recombinant genotypes of noroviruses, which include RNA-polymerase GII[16], have become globally widespread. The aim of the research was to analyze the genetic diversity of noroviruses circulating in 2016–2021 in the Republic of Belarus in order to establish the contribution of the identified genotypes to the formation of morbidity and to study the features of the circulation of their recombinant variants containing RNA polymerase GII [P16]. Sequencing and genetic analysis of a fragment of the ORF1 / ORF2 genome of 242 noroviruses from patients with AGE collected in 2016-2021 was carried out. It was found that 199 norovirus isolates (82.2% of all identified) were recombinant. During this period, genotypes containing GII.P16 polymerase and the VP1 gene of genotypes GII.2, GII.3, GII.4, GII.12, GII.13 prevailed (143 isolates, 71.9% of all recombinant genotypes). The proportion of individual recombinant genotypes was distributed as follows: GII.4 [P16] - 42.0%, GII.2 [P16] - 32.2%, GII.3 [P16] - 16.8%, GII.12 [P16] - 8.4%, GII.13 [P16] - 0.7%. The genotypes GII.4 [P16] and GII.2 [P16] circulated for the longest time - from 2016-2017 to 2021. Their circulation was accompanied by the emergence of outbreaks of AGE: genotype GII.2 [P16] caused outbreaks in 2016, 2018 and 2021, GII.4 [P16] - in 2017 and 2021. All investigated isolates of different recombinant genotypes contained the same variant of the GII.P16 RNA polymerase gene, which became globally distributed in the world in 2015-2017. Comparison of the nucleotide sequences of isolates within genotypes showed that, despite the long circulation period, there were no accumulation of mutations and no selection of genovariants within the genotype.
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