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1.
Microbiol Immunol ; 68(2): 56-64, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38098134

RESUMO

Vaccine development for herpes simplex virus 2 (HSV-2) has been attempted, but no vaccines are yet available. A plasmid-based reverse genetics system for Rotavirus (RV), which can cause gastroenteritis, allows the generation of recombinant RV containing foreign genes. In this study, we sought to develop simian RV (SA11) as a vector to express HSV-2 glycoprotein D (gD2) and evaluated its immunogenicity in mice. We generated the recombinant SA11-gD2 virus (rSA11-gD2) and confirmed its ability to express gD2 in vitro. The virus was orally inoculated into suckling BALB/c mice and into 8-week-old mice. Serum IgG and IgA titers against RV and gD2 were measured by ELISA. In the 8-week-old mice inoculated with rSA11-gD2, significant increases in not only antibodies against RV but also IgG against gD2 were demonstrated. In the suckling mice, antibodies against RV were induced, but gD2 antibody was not detected. Diarrhea observed after the first inoculation of rSA11-gD2 in suckling mice was similar to that induced by the parent virus. A gD2 expressing simian RV recombinant, which was orally inoculated, induced IgG against gD2. This strategy holds possibility for genital herpes vaccine development.


Assuntos
Herpes Genital , Rotavirus , Animais , Camundongos , Herpesvirus Humano 2/genética , Rotavirus/genética , Genética Reversa , Proteínas do Envelope Viral/genética , Glicoproteínas/genética , Imunoglobulina G , Anticorpos Antivirais
2.
J Gen Virol ; 103(6)2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35749287

RESUMO

Avian rotavirus A (RVA) is one of major enteric pathogens that cause diarrhoea in young avian individuals. Importantly, some of the avian RVA strains of G18P[17] genotype are naturally transmitted to and cause clinical diseases in mammalian species, indicating their potential risks to animal health. Although molecular information on the pathogenesis by avian RVA strains will be useful for estimating their risks, the absence of a reverse genetics (RG) system for these strains has hindered the elucidation of their pathogenic mechanisms. In this study, we aimed to establish an RG system for the avian G18P[17] prototype strain PO-13, which was isolated from a pigeon in Japan in 1983 and was experimentally shown to be pathogenic in suckling mice. Transfection with plasmids expressing 11 genomic RNA segments of the strain resulted in rescue of the infectious virus with an artificially introduced genetic marker on its genome, indicating that an RG system for the PO-13 strain was successfully established. The rescued recombinant strain rPO-13 had biological properties almost identical to those of its wild-type strain (wtPO-13). Notably, both rPO-13 and wtPO-13 induced diarrhoea in suckling mice with similar efficiencies. It was thus demonstrated that the RG system will be useful for elucidating the pathogenic mechanisms of the PO-13 strain at the molecular level. This is the first report of the establishment of an RG system for an avian RVA strain.


Assuntos
Infecções por Rotavirus , Rotavirus , Animais , Columbidae , Diarreia/veterinária , Genoma Viral , Genótipo , Mamíferos , Camundongos , Filogenia , Genética Reversa/métodos , Rotavirus/genética , Infecções por Rotavirus/veterinária
3.
J Gen Virol ; 103(5)2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35639587

RESUMO

The group A rotavirus (RVA) genome comprising 11 double-stranded RNAs encodes six structural proteins (VP1-VP4, VP6, and VP7) and six non-structural proteins (NSP1-NSP6). Among these 12 rotaviral proteins, NSP6 has been less studied as to its function. We previously prepared a recombinant NSP6-deficient RVA derived from simian strain SA11-L2 by reverse genetics, and found that the NSP6-deficient virus grew well in cell culture, although its growth was less abundant than that of the parental SA11-L2 strain. In this study, we examined the potency of a recombinant RVA incapable of NSP6 expression to cause diarrhoea in suckling mice. The suckling mice infected with the NSP6-deficient virus apparently experienced diarrhoea, although the symptom was milder and the duration of diarrhoea was shorter than in the mice infected with the authentic SA11-L2 strain. Thus, together with the results obtained for cultured cells in the previous study, it can be concluded that NSP6 is not necessarily required for replication and pathogenicity in vitro and in vivo.


Assuntos
Infecções por Rotavirus , Rotavirus , Animais , Linhagem Celular , Células Cultivadas , Diarreia , Camundongos , Rotavirus/genética
4.
J Infect Chemother ; 28(2): 206-210, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34756573

RESUMO

INTRODUCTION: The ability to predict which patients with a history of coronavirus disease (COVID-19) will exhibit a high antibody titer is necessary for more efficient screening of potential convalescent plasma donors. We aimed to identify factors associated with a high immunoglobulin G (IgG) titer in Japanese convalescent plasma donors after COVID-19. METHODS: This cross-sectional study included volunteers undergoing screening for convalescent plasma donation after COVID-19. Serum anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) S-protein IgG antibodies were measured using a high-sensitivity chemiluminescence enzyme immunoassay. RESULTS: IgG antibodies were measured in 581 patients, 534 of whom had full information of selected independent variables. Multiple linear regression analysis revealed that increasing age (1.037 [1,025, 1.048]), days from symptom onset to sampling (0.997 [0.995, 0.998]), fever (1.664 [1.226, 2.259]), systemic corticosteroid use during SARS-CoV-2 infection (2.382 [1.576, 3.601]), and blood type AB (1.478 [1.032, 2.117]) predict antibody titer. CONCLUSION: Older participants, those who experienced fever during infection, those treated with systemic corticosteroids during infection, those from whom samples were obtained earlier after symptom onset, and those with blood type AB are the best candidates for convalescent plasma donation. Therefore, these factors should be incorporated into the screening criteria for convalescent plasma donation after SARS-CoV-2 infection.


Assuntos
Anticorpos Antivirais , COVID-19 , Doadores de Sangue , COVID-19/terapia , Estudos Transversais , Humanos , Imunização Passiva , Japão/epidemiologia , SARS-CoV-2 , Soroterapia para COVID-19
5.
J Gen Virol ; 102(4)2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33843576

RESUMO

With the recent establishment of robust reverse genetics systems for rotavirus, rotavirus is being developed as a vector to express foreign genes. However, insertion of larger sequences such as those encoding multiple foreign genes into the rotavirus genome has been challenging because the virus segments are small. In this paper, we attempted to insert multiple foreign genes into a single gene segment of rotavirus to determine whether it can efficiently express multiple exogenous genes from its genome. At first, we engineered a truncated NSP1 segment platform lacking most of the NSP1 open reading frame and including a self-cleaving 2A sequence (2A), which made it possible to generate a recombinant rotavirus stably expressing NanoLuc (Nluc) luciferase as a model foreign gene. Based on this approach, we then demonstrated the generation of a replication-competent recombinant rotavirus expressing three reporter genes (Nluc, EGFP, and mCherry) by separating them with self-cleaving 2As, indicating the capacity of rotaviruses as to the insertion of multiple foreign genes. Importantly, the inserted multiple foreign genes remained genetically stable during serial passages in cell culture, indicating the potential of rotaviruses as attractive expression vectors. The strategy described here will serve as a model for the generation of rotavirus-based vectors designed for the expression and/or delivery of multiple foreign genes.


Assuntos
Genes Reporter , Vetores Genéticos , RNA Viral , Genética Reversa , Rotavirus/genética , Animais , Linhagem Celular , Cricetinae , Haplorrinos , Plasmídeos , Rotavirus/fisiologia , Replicação Viral
6.
Virus Genes ; 57(4): 338-357, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34106412

RESUMO

The exact evolutionary patterns of human G4P[6] rotavirus strains remain to be elucidated. Such strains possess unique and strain-specific genotype constellations, raising the question of whether G4P[6] strains are primarily transmitted via independent interspecies transmission or human-to-human transmission after interspecies transmission. Two G4P[6] rotavirus strains were identified in fecal specimens from hospitalized patients with severe diarrhea in Thailand, namely, DU2014-259 (RVA/Human-wt/THA/DU2014-259/2014/G4P[6]) and PK2015-1-0001 (RVA/Human-wt/THA/PK2015-1-0001/2015/G4P[6]). Here, we analyzed the full genomes of the two human G4P[6] strains, which provided the opportunity to study and confirm their evolutionary origin. On whole genome analysis, both strains exhibited a unique Wa-like genotype constellation of G4-P[6]-I1-R1-C1-M1-A8-N1-T1-E1-H1. The NSP1 genotype A8 is commonly found in porcine rotavirus strains. Furthermore, on phylogenetic analysis, each of the 11 genes of strains DU2014-259 and PK2015-1-0001 appeared to be of porcine origin. On the other hand, the two study strains consistently formed distinct clusters for nine of the 11 gene segments (VP4, VP6, VP1-VP3, and NSP2-NSP5), strongly indicating the occurrence of independent porcine-to-human interspecies transmission events. Our observations provide important insights into the origin of zoonotic G4P[6] strains, and into the dynamic interaction between porcine and human rotavirus strains.


Assuntos
Diarreia/genética , Infecções por Rotavirus/genética , Rotavirus/genética , Doenças dos Suínos/genética , Animais , Diarreia/virologia , Genoma Viral/genética , Humanos , Filogenia , Rotavirus/patogenicidade , Infecções por Rotavirus/transmissão , Infecções por Rotavirus/virologia , Especificidade da Espécie , Suínos/genética , Suínos/virologia , Doenças dos Suínos/transmissão , Doenças dos Suínos/virologia
7.
J Infect Chemother ; 27(10): 1533-1535, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34088604

RESUMO

Urinary antigen tests are a widely used rapid diagnostic method for Legionella pneumonia. However, conventional urinary antigen tests are unable to detect anything other than Legionella pneumophila serogroup 1. The Ribotest Legionella (Ribotest) can detect all serogroups by using antibodies recognizing L. pneumophila ribosomal protein L7/L12 in addition to the conventional L. pneumophila serogroup 1 lipopolysaccharide. The aim of this study was to evaluate the performance of Ribotest against conventional urinary antigen tests, including the detection of Legionellaceae other than L. pneumophila. We investigated the detection sensitivity of various kits using in-vitro culture-soluble antigen extracts of ATCC strains and 22 clinical isolates collected from multiple medical facilities in the Kinki region of Japan. For L. pneumophila serogroup 1, four kits, including Ribotest, had a detection sensitivity of 105 CFU/mL, with only Check Legionella having a sensitivity of 106 CFU/mL. L. pneumophila non-serogroup 1 and Legionellaceae of other species were undetectable by the four conventional kits, whereas Ribotest could detect them with a sensitivity of 105-108 CFU/mL. The Ribotest was also able to detect other species such as Legionella hackeliae, Legionella feeleii, Legionella anisa, Fluoribacter bozemanae, and Fluoribacter dumoffii, but the detection sensitivity of L. hackeliae and L. feeleii was 108 CFU/mL, which was much lower than that of the other strains. The Ribotest has high potential to be applied as a rapid diagnostic method for pneumonia caused by other species of Legionella and Fluoribacter.


Assuntos
Legionella pneumophila , Legionella , Doença dos Legionários , Humanos , Legionellaceae , Doença dos Legionários/diagnóstico , Kit de Reagentes para Diagnóstico , Proteínas Ribossômicas
8.
J Gen Virol ; 101(8): 806-815, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32490794

RESUMO

Reassortment is an important mechanism in the evolution of group A rotaviruses (RVAs), yielding viruses with novel genetic and phenotypic traits. The classical methods for generating RVA reassortants with the desired genetic combinations are laborious and time-consuming because of the screening and selection processes required to isolate a desired reassortant. Taking advantage of a recently developed RVA reverse genetics system based on just 11 cloned cDNAs encoding the RVA genome (11 plasmid-only system), we prepared a panel of simian SA11-L2 virus-based single-gene reassortants, each containing 1 segment derived from human KU virus of the G1P[8] genotype. It was shown that there was no gene-specific restriction of the reassortment potential. In addition to these 11 single-gene reassortants, a triple-gene reassortant with KU-derived core-encoding VP1-3 gene segments with the SA11-L2 genetic background, which make up a virion composed of the KU-based core, and SA11-L2-based intermediate and outer layers, could also be prepared with the 11 plasmid-only system. Finally, for possible clinical application of this system, we generated a series of VP7 reassortants representing all the major human RVA G genotypes (G1-4, G9 and G12) efficiently. The preparation of each of these single-gene reassortants was achieved within just 2 weeks. Our results demonstrate that the 11 plasmid-only system allows the rapid and reliable generation of RVA single-gene reassortants, which will be useful for basic research and clinical applications.


Assuntos
Genoma Viral/genética , Plasmídeos/genética , Vírus Reordenados/genética , Rotavirus/genética , Animais , Proteínas do Capsídeo/genética , Linhagem Celular , Cricetinae , DNA Complementar/genética , Genótipo , Haplorrinos , Humanos , RNA Viral/genética , Recombinação Genética/genética , Genética Reversa/métodos , Infecções por Rotavirus/virologia , Suínos
9.
J Virol ; 93(8)2019 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-30728265

RESUMO

The generation of recombinant group A rotaviruses (RVAs) entirely from cloned cDNAs has been described only for a single animal RVA strain, simian SA11-L2. We recently developed an optimized RVA reverse genetics system based on only RVA cDNAs (11-plasmid system), in which the concentration of cDNA plasmids containing the NSP2 and NSP5 genes is 3- or 5-fold increased in relation to that of the other plasmids. Based on this approach, we generated a recombinant human RVA (HuRVA)-based monoreassortant virus containing the VP4 gene of the simian SA11-L2 virus using the 11-plasmid system. In addition to this monoreassortant virus, authentic HuRVA (strain KU) was also generated with the 11-plasmid system with some modifications. Our results demonstrate that the 11-plasmid system involving just RVA cDNAs can be used for the generation of recombinant HuRVA and recombinant HuRVA-based reassortant viruses.IMPORTANCE Human group A rotavirus (HuRVA) is a leading pathogen causing severe diarrhea in young children worldwide. In this paper, we describe the generation of recombinant HuRVA (strain KU) from only 11 cloned cDNAs encoding the HuRVA genome by reverse genetics. The growth properties of the recombinant HuRVA were similar to those of the parental RVA, providing a powerful tool for better understanding of HuRVA replication and pathogenesis. Furthermore, the ability to manipulate the genome of HuRVAs "to order" will be useful for next-generation vaccine production for this medically important virus and for the engineering of clinical vectors expressing any foreign genes.


Assuntos
Clonagem Molecular , DNA Complementar/genética , Genoma Viral , Plasmídeos/genética , Rotavirus , Proteínas não Estruturais Virais , Animais , Linhagem Celular , Cricetinae , Humanos , Rotavirus/genética , Rotavirus/metabolismo , Proteínas não Estruturais Virais/genética , Proteínas não Estruturais Virais/metabolismo
10.
J Med Virol ; 92(2): 174-186, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31498444

RESUMO

Group A rotavirus (RVA) is a major cause of acute gastroenteritis in infants and young children worldwide. This study aims to clarify the distribution of G/P types and genetic characteristics of RVAs circulating in Thailand. Between January 2014 and September 2016, 1867 stool specimens were collected from children and adults with acute gastroenteritis in six provinces in Thailand. RVAs were detected in 514/1867 (27.5%) stool specimens. G1P[8] (44.7%) was the most predominant genotype, followed by G3P[8] (33.7%), G2P[4] (11.5%), G8P[8] (7.0%), and G9P[8] (1.3%). Unusual G3P[9] (0.8%), G3P[10] (0.4%), G4P[6] (0.4%), and G10P[14] (0.2%) were also detected at low frequencies. The predominant genotype, G1P[8] (64.4%), in 2014 decreased to 6.1% in 2016. In contrast, the frequency of G3P[8] markedly increased from 5.5% in 2014 to 65.3% in 2015 and 89.8% in 2016. On polyacrylamide gel electrophoresis, most (135/140; 96.4%) of the G3P[8] strains exhibited a short RNA profile. Successful determination of the nucleotide sequences of the VP7 genes of 98 G3P[8] strains with a short RNA profile showed that they are all equine-like G3P[8] strains. On phylogenetic analysis of genome segments of two representative Thai equine-like G3P[8] strains, it was noteworthy that they possessed distinct NSP4 genes, one bovine-like and the other human-like. Thus, we found that characteristic equine-like G3P[8] strains with a short RNA electropherotype are becoming highly prevalent in children and adults in Thailand.


Assuntos
Gastroenterite/virologia , Infecções por Rotavirus/epidemiologia , Infecções por Rotavirus/virologia , Rotavirus/classificação , Rotavirus/genética , Adolescente , Adulto , Animais , Criança , Pré-Escolar , Equidae , Fezes/virologia , Gastroenterite/epidemiologia , Genoma Viral , Genótipo , Humanos , Lactente , Recém-Nascido , Pessoa de Meia-Idade , Tipagem Molecular , Filogenia , Prevalência , RNA Viral/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA , Tailândia/epidemiologia , Adulto Jovem
11.
Microbiol Immunol ; 64(6): 401-406, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32293752

RESUMO

A reverse genetics technology is an incredibly useful technique both for a proper understanding of different aspects of virus biology and for the generation of complementary DNA (cDNA)-derived infectious viruses, which can act as safe and effective vaccines and viral vectors. Rotaviruses (RVAs), especially human RVAs (HuRVAs), had been very refractory to this technology until very recently. Here, we describe the historical background of the development of a long-awaited HuRVA reverse genetics system, culminating in the generation of replicative HuRVAs entirely from cloned cDNAs.


Assuntos
Genética Reversa/métodos , Rotavirus/genética , Animais , DNA Complementar/genética , Genoma Viral , Humanos , Plasmídeos/genética , RNA Viral/genética , Proteínas Virais/genética
12.
J Infect Chemother ; 26(9): 928-932, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32482514

RESUMO

BACKGROUND: The worldwide spread of organisms with antimicrobial resistance is of concern, especially the trend of significantly increasing carbapenemase-producing Enterobacterales (CPE). In this study, we investigated the annual trend of intestinal CPE carriage rates in inpatients and healthy adults in a primary care hospital in Tenri, Japan. METHODS: We collected 551 samples of feces from inpatients in our institution and 936 samples from healthy people living in Tenri city from December 2012 to April 2015. All samples were cultured on MacConkey agar plates containing 4 µg/mL ceftazidime for screening test. The colonies grown on the screening medium were detected for carbapenemase genes (blaIMP-1, blaIMP-2, blaVIM, blaKPC, blaGES, blaNDM, and blaOXA-48 groups) by multiplex PCR, and CPE were identified by MALDI-TOF MS. Plasmid replicon typing and pulsed-field gel electrophoresis (PFGE) were performed on PCR-positive strains. RESULTS: The CPE carriage rate was 1.6% (9/551) in the inpatient group and 0% (0/936) in the healthy adults group. The numbers of strains positive for the carbapenemase gene were 4 for Enterobacter cloacae, 2 for Klebsiella pneumoniae, 1 for Citrobacter freundii, 1 for Raoultella ornithinolytica and 1 for Escherichia coli. In all CPE strains, the carbapenemase gene was blaIMP-6 and the plasmid replicon type was IncN. The 4 E. cloacae strains showed a similar pattern in PFGE. CONCLUSION: In the same city in Japan, CPE intestinal carriers were detected only in the inpatient group in this study but not in a healthy adults, suggesting that the spread of asymptomatic CPE carriers was confined to inpatients.


Assuntos
Proteínas de Bactérias , beta-Lactamases , Adulto , Proteínas de Bactérias/genética , Enterobacteriaceae , Fezes , Hospitais , Humanos , Japão/epidemiologia , Atenção Primária à Saúde , beta-Lactamases/genética
13.
J Virol ; 92(13)2018 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-29669834

RESUMO

An entirely plasmid-based reverse genetics system for rotaviruses was established very recently. We improved the reverse genetics system to generate recombinant rotavirus by transfecting only 11 cDNA plasmids for its 11 gene segments under the condition of increasing the ratio of the cDNA plasmids for NSP2 and NSP5 genes. Utilizing this highly efficient system, we then engineered infectious recombinant rotaviruses expressing bioluminescent (NanoLuc luciferase) and fluorescent (enhanced green fluorescent protein [EGFP] and mCherry) reporters. These recombinant rotaviruses expressing reporters remained genetically stable during serial passages. Our reverse genetics approach and recombinant rotaviruses carrying reporter genes will be great additions to the tool kit for studying the molecular virology of rotavirus and for developing future next-generation vaccines and expression vectors.IMPORTANCE Rotavirus is one of the most important pathogens causing severe gastroenteritis in young children worldwide. In this paper, we describe a robust and simple reverse genetics system based on only rotavirus cDNAs and its application for engineering infectious recombinant rotaviruses harboring bioluminescent (NanoLuc) and fluorescent (EGFP and mCherry) protein genes. This highly efficient reverse genetics system and recombinant group A rotaviruses expressing reporters could be powerful tools for the study of different aspects of rotavirus replication. Furthermore, they may be useful for next-generation vaccine production for this medically important virus.


Assuntos
Proteínas de Fluorescência Verde/metabolismo , Rim/virologia , Genética Reversa , Infecções por Rotavirus/virologia , Rotavirus/fisiologia , Proteínas Virais/metabolismo , Animais , Células Cultivadas , Cricetinae , Proteínas de Fluorescência Verde/genética , Haplorrinos , Rim/metabolismo , Plasmídeos , RNA Viral , Infecções por Rotavirus/metabolismo , Replicação Viral
14.
J Infect Chemother ; 25(11): 837-844, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31427200

RESUMO

Obligate anaerobes exist as resident flora in various sites in humans, but they are also emphasized as endogenous causative microorganism of infections. We performed surveillance to understand the trend of drug susceptibility in obligate anaerobic bacteria in the Kinki area of Japan. In the experiment, we used 156 obligate anaerobe isolates collected from 13 institutions that participated in the Study of Bacterial Resistance Kinki Region of Japan. MALDI Biotyper was used to identify the collected strains, and among the 156 test strains, those that could be identified with an accuracy of Score Value 2.0 or more included 6 genera, 30 species, and 144 strains (Bacteroides spp. 77 strains, Parabacteroides sp. 2 strains, Prevotella spp. 29 strains, Fusobacterium spp. 14 strains, Porphyromonas spp. 2 strains, and Clostridioides difficile 20 strains), and they were assigned as subject strains for drug susceptibility testing. The drug susceptibility test was carried out by broth microdilution method using Kyokuto Opt Panel MP ANA (Kyokuto Pharmaceutical Industrial Co., Ltd., Tokyo, Japan) and judged according to CLSI criteria. As a result, Bacteroides and Parabacteroides species showed good sensitivities to tazobactam-piperacillin, imipenem, metronidazole and chloramphenicol, and low sensitivities to ampicillin, cefoperazone and vancomycin. Prevotella species showed good sensitivities to sulbactam-ampicillin, tazobactam-piperacillin, cefmetazole, imipenem, doripenem and metronidazole. Susceptibility rates to other drugs were slightly different depending on the bacterial species. Both Fusobacterium spp. and Porphyromonas spp. showed high sensitivities to many drugs. C. difficile was highly sensitive to vancomycin and metronidazole, having MIC90s of 0.5 µg/mL and ≤2 µg/mL, respectively.


Assuntos
Anti-Infecciosos/uso terapêutico , Bactérias Anaeróbias/efeitos dos fármacos , Infecções Bacterianas/tratamento farmacológico , Infecções Bacterianas/microbiologia , Farmacorresistência Bacteriana/efeitos dos fármacos , Humanos , Japão , Testes de Sensibilidade Microbiana
15.
Uirusu ; 69(1): 1-12, 2019.
Artigo em Japonês | MEDLINE | ID: mdl-32938889

RESUMO

An entirely plasmid-based reverse genetics system for animal rotavirus was established very recently. We improved the reverse genetics system to generate recombinant rotavirus by transfecting only 11 T7 plasmids for its 11 genes under the condition of increasing the ratio (3- or 5-fold) of the cDNA plasmids for NSP2 and NSP5 genes (11-plasmid system). Utilizing this highly efficient system, we engineered the first infectious recombinant rotaviruses harboring fluorescent (EGFP and mCherry) protein genes. In addition to these recombinant animal viruses, the first infectious recombinant human rotavirus (strain KU (G1P[8])) was also generated with the 11-plasmid system with some modifications. The availability of recombinant human rotaviruses will provide a genetic platform for a better understanding of the replication, pathogenicity, and other biological characteristics of this medically important virus and enable the rational development of next-generation human rotavirus vaccines.

16.
J Virol ; 91(21)2017 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-28794037

RESUMO

The use of overlapping open reading frames (ORFs) to synthesize more than one unique protein from a single mRNA has been described for several viruses. Segment 11 of the rotavirus genome encodes two nonstructural proteins, NSP5 and NSP6. The NSP6 ORF is present in the vast majority of rotavirus strains, and therefore the NSP6 protein would be expected to have a function in viral replication. However, there is no direct evidence of its function or requirement in the viral replication cycle yet. Here, taking advantage of a recently established plasmid-only-based reverse genetics system that allows rescue of recombinant rotaviruses entirely from cloned cDNAs, we generated NSP6-deficient viruses to directly address its significance in the viral replication cycle. Viable recombinant NSP6-deficient viruses could be engineered. Single-step growth curves and plaque formation of the NSP6-deficient viruses confirmed that NSP6 expression is of limited significance for RVA replication in cell culture, although the NSP6 protein seemed to promote efficient virus growth.IMPORTANCE Rotavirus is one of the most important pathogens of severe diarrhea in young children worldwide. The rotavirus genome, consisting of 11 segments of double-stranded RNA, encodes six structural proteins (VP1 to VP4, VP6, and VP7) and six nonstructural proteins (NSP1 to NSP6). Although specific functions have been ascribed to each of the 12 viral proteins, the role of NSP6 in the viral replication cycle remains unknown. In this study, we demonstrated that the NSP6 protein is not essential for viral replication in cell culture by using a recently developed plasmid-only-based reverse genetics system. This reverse genetics approach will be successfully applied to answer questions of great interest regarding the roles of rotaviral proteins in replication and pathogenicity, which can hardly be addressed by conventional approaches.


Assuntos
Regulação Viral da Expressão Gênica , Genética Reversa , Infecções por Rotavirus/virologia , Rotavirus/fisiologia , Proteínas não Estruturais Virais/metabolismo , Replicação Viral/fisiologia , Animais , Células Cultivadas , Cricetinae , Humanos , Fases de Leitura Aberta , Proteínas não Estruturais Virais/genética
17.
J Med Virol ; 90(5): 890-898, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29315643

RESUMO

The emergence and rapid spread of novel DS-1-like intergenogroup reassortant rotaviruses having the equine-like G3 genotype (DS-1-like G3P[8] strains) have been recently reported from several countries. During rotavirus surveillance in Japan in 2015-2016, three DS-1-like G3P[8] strains were identified from children with severe diarrhea. In the present study, we sequenced and characterized the full genomes of these three strains. On full-genomic analysis, all three strains showed a unique genotype constellation including both genogroup 1 and 2 genes: G3-P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2. Phylogenetic analysis revealed that each of the 11 genes of the three strains was closely related to that of Japanese DS-1-like G1P[8] and/or Japanese equine-like G3P[4] human strains. Thus, the three study strains were suggested to be reassortants that acquired the G3-VP7 gene from equine G3 rotaviruses on the genetic background of DS-1-like G1P[8] strains. Our observations will provide important insights into the evolutionary dynamics of emerging DS-1-like G3P[8] strains.


Assuntos
Diarreia/virologia , Genótipo , Vírus Reordenados/classificação , Vírus Reordenados/isolamento & purificação , Infecções por Rotavirus/virologia , Rotavirus/classificação , Rotavirus/isolamento & purificação , Pré-Escolar , Feminino , Humanos , Lactente , Japão , Masculino , Filogenia , Vírus Reordenados/genética , Rotavirus/genética , Análise de Sequência de DNA , Sequenciamento Completo do Genoma
18.
J Infect Chemother ; 24(3): 171-176, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29361416

RESUMO

The 7-valent pneumococcal conjugate vaccine (PCV7) was introduced among children in Japan in 2010. There are no long-term multicenter surveillance studies of antimicrobial resistance in S. pneumoniae before and after the introduction of PCV7. Therefore, we examined chronological trends in antimicrobial resistance among 4534 strains of S. pneumoniae isolated from both children and adults in the Kinki region of Japan during 2001-2015. High-level penicillin and third-generation cephalosporin resistance in S. pneumoniae increased among both children and adults during the period before the introduction of PCV7 (2001-2010). Besides penicillin and cephalosporin, pneumococcal carbapenem and macrolide resistance increased among children. The rate of resistance to these antibiotics was higher among children than among adults. The introduction of PCV7 decreased the rate of non-susceptibility to ß-lactam antibiotics and the rate of multidrug resistant S. pneumoniae among children, but not among adults.


Assuntos
Farmacorresistência Bacteriana Múltipla , Vacina Pneumocócica Conjugada Heptavalente/administração & dosagem , Infecções Pneumocócicas/microbiologia , Infecções Pneumocócicas/prevenção & controle , Streptococcus pneumoniae/isolamento & purificação , Adulto , Carbapenêmicos/uso terapêutico , Cefalosporinas/uso terapêutico , Criança , Monitoramento Epidemiológico , Humanos , Japão/epidemiologia , Macrolídeos/uso terapêutico , Penicilinas/uso terapêutico , Infecções Pneumocócicas/tratamento farmacológico , Infecções Pneumocócicas/epidemiologia , Estudos Retrospectivos , Streptococcus pneumoniae/efeitos dos fármacos , Streptococcus pneumoniae/imunologia
19.
J Infect Chemother ; 24(4): 262-266, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29248418

RESUMO

Carbapenemase-producing Enterobacteriaceae (CPE) are increasing worldwide. Rapid and accurate detection of CPE is necessary for appropriate antimicrobial treatment and hospital infection control. However, CPE contains some strains that are difficult to detect depending on genotype and MIC value of carbapenem, and a detection method has not been established. The recently reported modified carbapenem inactivation method (mCIM) has been developed in CLSI M100-S27 as a phenotypic technique for detecting carbapenemase activity. In the present study, we examined mCIM as a new CPE detection method using 207 Enterobacteriaceae isolates in comparison with the three existing screening methods of modified Hodge test, Carba NP test and carbapenem inactivation method and evaluated its performance. Consequently, both the sensitivity and specificity of mCIM were 100%, indicating better results than the conventional screening methods. The mCIM is a useful tool for microbiology laboratories due to its simplicity, clear criteria, cost-effectiveness and availability at any laboratory.


Assuntos
Proteínas de Bactérias/metabolismo , Técnicas de Tipagem Bacteriana/métodos , Enterobacteriáceas Resistentes a Carbapenêmicos/isolamento & purificação , Carbapenêmicos/farmacologia , Ensaios Enzimáticos/métodos , beta-Lactamases/metabolismo , Técnicas de Tipagem Bacteriana/economia , Enterobacteriáceas Resistentes a Carbapenêmicos/classificação , Enterobacteriáceas Resistentes a Carbapenêmicos/efeitos dos fármacos , Enterobacteriáceas Resistentes a Carbapenêmicos/enzimologia , Infecções por Enterobacteriaceae/microbiologia , Ensaios Enzimáticos/economia , Testes de Sensibilidade Microbiana , Sensibilidade e Especificidade
20.
J Gen Virol ; 98(4): 532-538, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28382902

RESUMO

An unusual rotavirus strain with the G9P[23] genotype (RVA/Human-wt/THA/KKL-117/2014/G9P[23]) was identified in a stool specimen from a 10-month-old child hospitalized with severe diarrhoea. In this study, we sequenced and characterized the complete genome of strain KKL-117. On full-genomic analysis, strain KKL-117 was found to have the following genotype constellation: G9-P[23]-I5-R1-C1-M1-A8-N1-T1-E1-H1. The non-G/P genotype constellation of this strain (I5-R1-C1-M1-A8-N1-T1-E1-H1) is commonly shared with rotavirus strains from pigs. Furthermore, phylogenetic analysis indicated that each of the 11 genes of strain KKL-117 appeared to be of porcine origin. Our observations provide important insights into the dynamic interactions between human and porcine rotavirus strains.


Assuntos
Diarreia/virologia , Genótipo , Infecções por Rotavirus/virologia , Rotavirus/classificação , Rotavirus/genética , Animais , Análise por Conglomerados , Fezes/virologia , Genoma Viral , Humanos , Lactente , Filogenia , Rotavirus/isolamento & purificação , Infecções por Rotavirus/transmissão , Análise de Sequência de DNA , Homologia de Sequência , Suínos , Tailândia , Zoonoses/transmissão , Zoonoses/virologia
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