| 281. |
- Torell, Erik, et al.
(författare)
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Near absence of VRE but high carriage rates of quinolone-resistant ampicillin-resistant enterococci among hospitalized patients and non-hospitalized individuals in Sweden
- 1999
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 37:11, s. 3509-3513
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Tidskriftsartikel (refereegranskat)abstract
- Rates of colonization with enterococci with acquired resistance to vancomycin (vancomycin-resistant enterococci [VRE]) and ampicillin (ampicillin-resistant enterococci [ARE]) were determined by using fecal samples from 670 nonhospitalized individuals and 841 patients in 27 major hospitals. Of the hospitalized patients, 181 (21.5%) were carriers of ARE and 9 (1.1%) were carriers of VRE. In univariate analyses, length of hospital stay (odds ratio [OR], 4.6; 95% confidence interval [CI], 2.5 to 8.9) and antimicrobial therapy (OR, 4.7; 95% CI, 3.3 to 6.7) were associated with ARE colonization, as were prior treatment with penicillins (OR, 3.1; 95% CI, 1.8 to 5. 5), cephalosporins (OR, 2.9; 95% CI, 1.7 to 5.0), or quinolones (OR, 2.7; 95% CI, 1.5 to 4.7). In logistic regression analysis, antimicrobial therapy for at least 5 days was independently associated with ARE carriage (adjusted OR, 3.8; 95% CI, 2.6 to 5.4). Over 90% of the ARE isolates were fluoroquinolone resistant, whereas 14% of the ampicillin-susceptible Enterococcus faecium isolates were fluoroquinolone resistant. ARE carriage rates correlated with the use of fluoroquinolones (P = 0.04) but not with the use of ampicillin (P = 0.68) or cephalosporins (P = 0.40). All nine VRE isolates were E. faecium vanB and were found in one hospital. Seven of these isolates were related according to their types as determined by pulsed-field gel electrophoresis. Among the nonhospitalized individuals, the ARE carriage rate was lower (6%; P < 0.05), and only one person, who had recently returned from Africa, harbored VRE (E. faecium vanA). The absence of VRE colonization in nonhospitalized individuals reflects an epidemiological situation in Sweden radically different from that in countries in continental Europe where glycopeptides have been widely used for nonmedical purposes.
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| 282. |
- Tyson, Jasmine, et al.
(författare)
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Combination of Nonstructural Protein 1-Based Enzyme-Linked Immunosorbent Assays Can Detect and Distinguish Various Dengue Virus and Zika Virus Infections
- 2019
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Ingår i: Journal of Clinical Microbiology. - : AMER SOC MICROBIOLOGY. - 0095-1137 .- 1098-660X. ; 57:2
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Tidskriftsartikel (refereegranskat)abstract
- The recent outbreaks of Zika virus (ZIKV) and associated birth defects in regions of dengue virus (DENV) endemicity emphasize the need for sensitive and specific serodiagnostic tests. We reported previously that enzyme-linked immunosor- bent assays (ELISAs) based on the nonstructural protein 1 (NS1) of DENV serotype 1 (DENV1) and ZIKV can distinguish primary DENV1, secondary DENV, and ZIKV infections. Whether ELISAs based on NS1 proteins of other DENV serotypes can discriminate various DENV and ZIKV infections remains unknown. We herein developed DENV2, DENV3, and DENV4 NS1 IgG ELISAs to test convalescent- and postconvalescent-phase samples from reverse transcription-PCR-confirmed cases, including 25 primary DENV1, 24 primary DENV2, 10 primary DENV3, 67 secondary DENV, 36 primary West Nile virus, 38 primary ZIKV, and 35 ZIKV with previous DENV infections as well as 55 flavivirus-naive samples. Each ELISA detected primary DENV infection with a sensitivity of 100% for the same serotype and 23.8% to 100% for different serotypes. IgG ELISA using a mixture of DENV1-4 NS1 proteins detected different primary and secondary DENV infections with a sensitivity of 95.6% and specificity of 89.5%. The ZIKV NS1 IgG ELISA detected ZIKV infection with a sensitivity of 100% and specificity of 82.9%. On the basis of the relative optical density ratio, the combination of DENV1-4 and ZIKV NS1 IgG ELISAs distinguished ZIKV with previous DENV and secondary DENV infections with a sensitivity of 91.7% to 94.1% and specificity of 87.0% to 95.0%. These findings have important applications to serodiagnosis, serosurveillance, and monitoring of both DENV and ZIKV infections in regions of endemicity.
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| 283. |
- Törös, Bianca, 1987-, et al.
(författare)
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Genome-based characterization of emergent invasive Neisseria meningitidis serogroup Y isolates in Sweden from 1995 to 2012
- 2015
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 53:7, s. 2154-2162
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Tidskriftsartikel (refereegranskat)abstract
- Invasive meningococcal disease (IMD) caused by Neisseria meningitidis serogroup Y has increased in Europe, especially in Scandinavia. In Sweden, serogroup Y is now the dominating serogroup, and in 2012, the serogroup Y disease incidence was 0.46/100,000 population. We previously showed that a strain type belonging to sequence type 23 was responsible for the increased prevalence of this serogroup in Sweden. The objective of this study was to investigate the serogroup Y emergence by whole-genome sequencing and compare the meningococcal population structure of Swedish invasive serogroup Y strains to those of other countries with different IMD incidence. Whole-genome sequencing was performed on invasive serogroup Y isolates from 1995 to 2012 in Sweden (n = 186). These isolates were compared to a collection of serogroup Y isolates from England, Wales, and Northern Ireland from 2010 to 2012 (n = 143), which had relatively low serogroup Y incidence, and two isolates obtained in 1999 in the United States, where serogroup Y remains one of the major causes of IMD. The meningococcal population structures were similar in the investigated regions; however, different strain types were prevalent in each geographic region. A number of genes known or hypothesized to have an impact on meningococcal virulence were shown to be associated with different strain types and subtypes. The reasons for the IMD increase are multifactorial and are influenced by increased virulence, host adaptive immunity, and transmission. Future genome-wide association studies are needed to reveal additional genes associated with serogroup Y meningococcal disease, and this work would benefit from a complete serogroup Y meningococcal reference genome.
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| 284. |
- Ulleryd, Peter, 1958, et al.
(författare)
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Colonization with Escherichia coli Strains among Female Sex Partners of Men with Febrile Urinary Tract Infection
- 2015
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Ingår i: Journal of Clinical Microbiology. - : American Society for Microbiology. - 0095-1137 .- 1098-660X. ; 53:6, s. 1947-1950
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Tidskriftsartikel (refereegranskat)abstract
- Of 23 unique Escherichia coli strains from 10 men with febrile urinary tract infections (UTIs) and their female sex partners, 6 strains (all UTI causing) were shared between partners. Molecularly, the 6 shared strains appeared more virulent than the 17 nonshared strains, being associated with phylogenetic group B2, sequence types ST73 and ST127, and multiple specific virulence genes. This indicates that UTIs are sometimes sexually transmitted.
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| 285. |
- Unemo, Magnus, 1970-, et al.
(författare)
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Comparison of serologic and genetic porB-based typing of Neisseria gonorrhoeae : consequences for future characterization
- 2003
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 41:9, s. 4141-4147
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Tidskriftsartikel (refereegranskat)abstract
- Due to temporal changes in the epidemiology of gonorrhea, a precise characterization of Neisseria gonorrhoeae is essential. In the present study genetic heterogeneity in the porB genes of N. gonorrhoeae was examined, and serovar determination was compared to porB gene sequencing. Among 108 N. gonorrhoeae isolates, phylogenetic analysis of the entire porB alleles (924 to 993 bp) identified 87 unique sequences. By analyzing only the four to six most heterogeneous porB gene regions (174 to 363 bp), 86 out of these 87 genetic variants were identified. Consequently, analysis of shorter highly variable regions of the porB gene generates high-level discriminatory ability as well as fast, objective, reproducible, and portable data for epidemiological characterization of N. gonorrhoeae. Regarding putative antigenic epitopes of PorB for Genetic Systems monoclonal antibodies (MAbs), some of the previous findings were confirmed, but new findings were also observed. For several of the MAbs, however, the precise amino acid residues of PorB critical for single-MAb reactivity were difficult to identify. In addition, repeated serovar determination of 108 N. gonorrhoeae isolates revealed discrepancies for 34 isolates, mostly due to nonreproducible reactivity with single MAbs. Thus, the prospects of a genetic typing system with congruent translation of the serovar determination seem to be limited. In conclusion, analysis of short highly variable regions of the porB gene could form the basis for a fast molecular epidemiological tool for the examination of emergence and transmission of N. gonorrhoeae strains within the community.
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| 286. |
- Unemo, Magnus, 1970-, et al.
(författare)
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Molecular epidemiology of Neisseria gonorrhoeae : sequence analysis of the porB gene confirms presence of two circulating strains
- 2002
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 40:10, s. 3741-3749
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Tidskriftsartikel (refereegranskat)abstract
- The phenotypic and genotypic characteristics of Neisseria gonorrhoeae strains fluctuate over time both locally and globally, and highly discriminative and precise characterization of the strains is essential. Conventional characterization of N. gonorrhoeae strains for epidemiological purposes is mostly based on phenotypic methods, which have some inherent limitations. In the present study sequence analysis of porB1b gene sequences was used for examination of the genetic relationships among N. gonorrhoeae strains. Substantial genetic heterogeneity was identified in the porB genes of serovar IB-2 isolates (8.1% of the nucleotide sites were polymorphic) and serovar IB-3 isolates (5.2% of the nucleotide sites were polymorphic) as well as between isolates of different serovars. The highest degree of diversity was identified in the gene segments encoding the surface-exposed loops of the mature PorB protein. Phylogenetic analysis of the porB1b gene sequences confirmed previous findings that have indicated the circulation of one N. gonorrhoeae strain each of serovar IB-2 and serovar IB-3 in the Swedish community. These strains caused the majority of the cases in two domestic core groups comprising homosexual men and young heterosexuals, respectively, and were also detected in other patients. The phylogenetic analyses of porB gene sequences in the present study showed congruence, but not complete identity, with previous results obtained by pulsed-field gel electrophoresis of the same isolates. In conclusion, porB gene sequencing can be used as a molecular epidemiological tool for examination of genetic relationships among emerging and circulating N. gonorrhoeae strains, as well as for confirmation or discrimination of clusters of gonorrhea cases.
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| 287. |
- Unemo, Magnus, 1970-, et al.
(författare)
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Molecular typing of Neisseria gonorrhoeae isolates by pyrosequencing of highly polymorphic segments of the porB gene
- 2004
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 42:7, s. 2926-2934
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Tidskriftsartikel (refereegranskat)abstract
- For prevention and control of gonorrhea, an objective, highly discriminating, and reproducible molecular epidemiological characterization of Neisseria gonorrhoeae is essential. In the present study, in pursuance of providing such qualities, pyrosequencing technology, a fast real-time DNA sequence analysis, was applied to six short, highly polymorphic porB gene segments, with subsequent genetic variant (genovar) determination of the bacterial isolates. The sequencing templates were obtained by real-time PCR amplification, which also included fluorescence melting curve analysis of the entire porB gene in order to determine the genogroup (porB1a or porB1b allele) prior to pyrosequencing analysis. The PSQ 96 MA system used allowed rapid (in approximately 1.5 h) determination of 96 sequences of 20 to 65 correct nucleotides each. The results were reproducible and mostly in concordance with the results of conventional Sanger dideoxy sequencing, with the exception of shorter read lengths and some uncertainty in determining the correct number of identical nucleotides in homopolymeric segments. The number of sequence variants identified in each of the six highly polymorphic segments of the porB1a and porB1b alleles (encoding surface-exposed amino acid loops of the mature PorB protein) ranged from 5 to 11 and from 8 to 39, respectively. Among porB1a isolates (n = 22) and porB1b isolates (n = 65), 22 and 64 unique genovars, respectively, were identified. All isolates were typeable. The present results provide evidence of a high discriminatory ability, practically the same as that for sequencing of the entire porB gene. In conclusion, the fast and high-throughput pyrosequencing technology can be used for molecular epidemiological characterization of N. gonorrhoeae.
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| 288. |
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| 289. |
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| 290. |
- Vapalahti, O, et al.
(författare)
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Antigenic properties and diagnostic potential of puumala virus nucleocapsid protein expressed in insect cells
- 1996
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Ingår i: Journal of clinical microbiology. - : American Society for Microbiology. - 0095-1137 .- 1098-660X. ; 34:1, s. 119-125
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Tidskriftsartikel (refereegranskat)abstract
- Puumala virus (PUU) is a member of the genus Hantavirus in the family Bunyaviridae and the causative agent of nephropathia epidemica, a European form of hemorrhagic fever with renal syndrome. Sera of nephropathia epidemica patients react specifically with PUU nucleocapsid (N) protein. In order to safely provide large quantities of antigen for diagnostic purposes, PUU Sotkamo strain N protein was expressed by using the baculovirus system in Sf9 insect cells to up to 30 to 50% of the total cellular protein. The recombinant N protein (bac-PUU-N) was solubilized with 6 M urea, dialyzed, and purified by anion-exchange liquid chromatography. In an immunoglobulin M mu-capture assay purified and unpurified bac-PUU-N antigen showed identical results compared with the results of a similar assay based on native PUU antigen grown in Vero E6 cells. An immunoglobulin G monoclonal antibody-capture assay based on unpurified bac-PUU-N also showed results identical to those of an assay with native PUU-N antigen. Moreover, a panel of monoclonal antibodies reactive with eight different epitopes showed identical reactivity patterns with both natural and bac-PUU-N antigen, while two epitopes in PUU-N expressed as a fusion protein in Escherichia coli were not recognized. Puumala hantavirus N protein expressed by the baculovirus system offers a safe and inexpensive source of specific antigen for large-scale diagnostic and seroepidemiological purposes.
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