| 1. |
- Bucardo, F, et al.
(författare)
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Mutated G4P[8] rotavirus associated with a nationwide outbreak of gastroenteritis in Nicaragua in 2005
- 2007
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 45:3, s. 990-997
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Tidskriftsartikel (refereegranskat)abstract
- During February and March 2005, one of the largest national recorded outbreaks of severe acute gastroenteritis occurred in Nicaragua, affecting ≥64,000 individuals and causing ≥56 deaths, predominantly in children under 5 years of age. Through a nationwide laboratory-based study, stool samples were collected and investigated for rotavirus. Of 108 stool samples examined, 72 (67%) were positive for rotavirus. While 69% (50/72) of the positive samples were found in children less than 2 years of age, 50% (6/12) of the adult samples were positive. A mutated G4P[8] strain was the most commonly recognized strain (85%), followed by mixed G strains (8%) and G9P[8] (7%) strains. Phylogenetic analysis of the VP7 gene revealed that the G4 strains belonged to the emerging lineage Ic and was distantly related to the ST3 and VA70 G4 strains. Secondary structure predictions of the VP7 G4 protein revealed an insert of an asparagine residue in position 76, which, combined with additional mutations, surprisingly modified two downstream β-sheets at amino acid positions 80 to 85 and 115 to 119. The 2005 G4P[8] strain compared to a G4P[8] strain from 2002 had a substitution of an asparagine residue for threonine (Asn→Thr) at position 96 within antigenic region A, thus eliminating a potential glycosylation site. The mutated G4 virus was introduced in Nicaragua after 2002 and probably emerged from Brazil, Argentina, or Uruguay. Copyright © 2007, American Society for Microbiology. All Rights Reserved.
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| 2. |
- Bucardo, Filemon, et al.
(författare)
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Pediatric norovirus diarrhea in Nicaragua
- 2008
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 46:8, s. 2573-2580
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Tidskriftsartikel (refereegranskat)abstract
- Information about norovirus (NoV) infections in Central America is limited. Through a passive community and hospital pediatric diarrhea surveillance program, a total of 542 stool samples were collected between March 2005 and February 2006 in León, Nicaragua. NoV was detected in 12% (65/542) of the children; of these, 11% (45/409) were in the community and 15% (20/133) were in the hospital, with most strains (88%) belonging to genogroup II. NoV infections were age and gender associated, with children of <2 years of age (P < 0.05) and girls (P < 0.05) being most affected. Breast-feeding did not reduce the number of NoV infections. An important proportion (57%) of NoV-infected children were coinfected with diarrheagenic Escherichia coli. A significant proportion (18/31) of NoV-positive children with dehydration required intravenous rehydration. Nucleotide sequence analysis (38/65) of the N-terminal and shell region in the capsid gene revealed that at least six genotypes (GI.4, GII.2, GII.4, GII.7, GII.17, and a potentially novel cluster termed "GII.18-Nica") circulated during the study period, with GII.4 virus being predominant (26/38). The majority (20/26) of those GII.4 strains shared high nucleotide homology (99%) with the globally emerging Hunter strain. The mean viral load was approximately 15-fold higher in children infected with GII.4 virus than in those infected with other G.II viruses, with the highest viral load observed for the group of children infected with GII.4 and requiring intravenous rehydration. This study, the first of its type from a Central American country, suggests that NoV is an important etiological agent of acute diarrhea among children of <2 years of age in Nicaragua.
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| 3. |
- Kindberg, Elin, 1981-, et al.
(författare)
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Host genetic resistance to symptomatic norovirus (GGII.4) infections in Denmark
- 2007
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 45:8, s. 2720-2
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Tidskriftsartikel (refereegranskat)abstract
- A total of 61 individuals involved in five norovirus outbreaks in Denmark were genotyped at nucleotides 428 and 571 of the FUT2 gene, determining secretor status, i.e., the presence of ABH antigens in secretions and on mucosa. A strong correlation (P = 0.003) was found between the secretor phenotype and symptomatic disease, extending previous knowledge and confirming that nonsense mutations in the FUT2 gene provide protection against symptomatic norovirus (GGII.4) infections. Copyright © 2007, American Society for Microbiology. All Rights Reserved.
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| 4. |
- Mittelholzer, C., et al.
(författare)
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Detection and Sequence Analysis of Danish and Swedish Strains of Mink Astrovirus
- 2003
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 41:11, s. 5192-5194
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Tidskriftsartikel (refereegranskat)abstract
- The sequences of mink astroviruses collected from 11 farms in Denmark and Sweden were analyzed and found to be homologous with one another but different from those of other astroviruses. A species-specific reverse transcriptase-PCR for mink astrovirus was established and shown to be suitable for the analysis of clinical samples.
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| 5. |
- Nenonen, Nancy P., et al.
(författare)
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Norovirus GII.4 Detection in Environmental Samples from Patient Rooms during Nosocomial Outbreaks
- 2014
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Ingår i: Journal of Clinical Microbiology. - : American Society for Microbiology. - 0095-1137 .- 1098-660X. ; 52:7, s. 2352-2358
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Tidskriftsartikel (refereegranskat)abstract
- Norovirus (NoV) is an important cause of nosocomial gastroenteric outbreaks. This 5-month study was designed to characterize NoV contamination and airborne dispersal in patient rooms during hospital outbreaks. Air vents, overbed tables, washbasins, dust, and virus traps designed to collect charged particles from the air were swabbed to investigate the possibility of NoV contamination in patient rooms during outbreaks in seven wards and in an outbreak-free ward. Symptomatic inpatients were also sampled. Nucleic acid extracts of the samples were examined for NoV RNA using genogroup I (GI) and GII real-time reverse transcription-PCR (RT-PCR). The NoV strains were characterized by RT-PCR, sequencing, and phylogenetic analysis of the RNA-dependent RNA-polymerase-N/S capsid-coding region (1,040 nucleotides [nt]). Patient strains from two outbreaks in one ward were sequenced across the RNA-dependent-RNA-polymerase major capsid-coding region (2.5 kb), including the hypervariable P2 domain. In the outbreak wards, NoV GII was detected in 48 of 101 (47%) environmental swabs and 63 of 108 patients (58%); NoV genotype II.4 was sequenced from 18 environmental samples, dust (n = 8), virus traps (n = 4), surfaces (n = 6), and 56 patients. In contrast, NoV GII was detected in 2 (GII. 4) of 28 (7%) environmental samples and in 2 (GII. 6 and GII. 4) of 17 patients in the outbreak-free ward. Sequence analyses revealed a high degree of similarity (greater than99.5%, 1,040 nt) between NoV GII.4 environmental and patient strains from a given ward at a given time. The strains clustered on 11 subbranches of the phylogenetic tree, with strong correlations to time and place. The high nucleotide similarity between the NoV GII.4 strains from patients and their hospital room environment provided molecular evidence of GII.4 dispersal in the air and dust; therefore, interventional cleaning studies are justified.
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| 6. |
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| 7. |
- Nordgren, Johan, et al.
(författare)
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Novel Light-Upon-Extension Real-Time PCR Assay for Simultaneous Detection, Quantification, and Genogrouping of Group A Rotavirus
- 2010
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Ingår i: JOURNAL OF CLINICAL MICROBIOLOGY. - : American Society for Microbiology. - 0095-1137. ; 48:5, s. 1859-1865
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Tidskriftsartikel (refereegranskat)abstract
- We have developed a light-upon-extension (LUX) real-time PCR assay for detection, quantification, and genogrouping of group A rotavirus (RV), the most common cause of acute gastroenteritis in children. The LUX system uses a fluorophore attached to one primer and having a self-quenching hairpin structure, making it cost-effective and specific. We designed genogroup-specific primers having different fluorophores, making it possible to differentiate between the two main genogroups of human group A RVs. The assay was applied on clinical stool specimens from Sweden and Central America (n = 196) and compared to immunological and conventional PCR assays. The genogrouping ability was further validated against a subset of clinical specimens, which had been genogrouped using monoclonal antibodies. Our real-time PCR assay detected and quantified all positive specimens (n = 145) and exhibited higher sensitivity than immunological assays and conventional PCR. The assay exhibited a wide dynamic range, detecting from 5 to andgt; 10(7) genes per PCR, resulting in a theoretical lower detection limit of andlt; 10,000 viruses per gram of stool. No cross-reaction was observed with specimens containing norovirus, sapovirus, astrovirus, or adenovirus. In total, 22 (15%) of the positive clinical specimens were identified as genogroup I, 122 (84%) were identified as genogroup II, and 1 specimen was found to contain a mix of both genogroups. All genogroup I-positive specimens were associated with capsid glycoprotein 2 (G2). No significant difference in viral load was found between genogroups or geographic region. The detection and quantification, combined with the genogrouping ability, make this assay a valuable tool both for diagnostics and for molecular epidemiological investigations.
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| 8. |
- Nordgren, Johan, 1980-, et al.
(författare)
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Novel light-upon-extension real-time PCR assays for detection and quantification of genogroup I and II noroviruses in clinical specimens
- 2008
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 46:1, s. 164-170
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Tidskriftsartikel (refereegranskat)abstract
- Norovirus is now recognized as the leading cause of nonbacterial acute gastroenteritis in adults, causing numerous outbreaks worldwide. We have developed two novel light-upon-extension (LUX) real-time PCR assays for detection and quantification of norovirus genogroups I and II. The LUX system uses a fluorophore attached to one primer having a self-quenching hairpin structure, making it cost-effective and specific. The assays were evaluated against clinical stool specimens (n = 103) from Sweden and Nicaragua and compared to established methods. The norovirus assay detected more positive stool specimens (47/103) than conventional PCR (39/103) and corresponded to a TaqMan real-time PCR, with the exception of one specimen. Furthermore, the assays correctly identified all (n = 11) coded control specimens in a reference panel containing various genogroups and genotypes. Both LUX real-time PCR assays had a wide dynamic range, detecting from < or = 10(1) to 10(7) genes per reaction, resulting in a theoretical lower limit of < or = approximately 20,000 viruses per gram of stool. No cross-reactivity was noticed with specimens containing other enteric viruses, and by using melting curve analysis we could differentiate between norovirus genogroups I and II.
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| 9. |
- Rubilar-Abreu, Elba, et al.
(författare)
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Serotype G9 rotavirus infections in adults in Sweden
- 2005
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 43:3, s. 1374-1376
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Tidskriftsartikel (refereegranskat)abstract
- Rotavirus is a major cause of acute gastroenteritis. By examining 1,517 stool samples collected in 2001 and 2002 from Swedish adults with acute diarrhea, rotavirus was found in 3.2%, with the emerging G9P[8] serotype being the one most commonly identified (42.9%). This is the first documentation of G9 infections in adults in Europe. Copyright © 2005, American Society for Microbiology. All Rights Reserved.
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| 10. |
- Tiveljung Lindell, Annika, et al.
(författare)
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Molecular epidemiology of norovirus infections in Stockholm, Sweden, during the years 2000 to 2003 : Association of the GGIIb genetic cluster with infection in children
- 2005
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 43:3, s. 1086-1092
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Tidskriftsartikel (refereegranskat)abstract
- The incidence of norovirus-associated gastroenteritis and the molecular epidemiology of norovirus strains were studied during three seasons (2000-2001, 2001-2002, and 2002-2003) among patients of all ages, mainly from the Stockholm region in Sweden. A total of 3,252 fecal samples were analyzed by reverse transcription-PCR. The incidences of norovirus infection among adults were 23, 26, and 30% during the three seasons studied and 18,11, and 15% among children 0 to 15 years of age. During the first season, all norovirus strains detected by PCR were typed either by reverse line blot hybridization or nucleotide sequence analysis. During the two successive seasons, a total of 60 norovirus-positive strains from the beginning, peak, and end of the seasons were selected for nucleotide sequence analysis. We identified two dominant noroviras variants over the seasons: a new norovirus variant, recently described as the GGIIb genetic cluster, dominated among children during the first season, and during the following two seasons, a GGII-4 variant dominated. Our data suggest that norovirus infections are common, not only among adults, but also among children, and that some strains may predominantly affect children. Copyright © 2005, American Society for Microbiology. All Rights Reserved.
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