| 1. |
- Backman, Anders, et al.
(författare)
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Evaluation of an extended diagnostic PCR assay for detection and verification of the common causes of bacterial meningitis in CSF and other biological samples
- 1999
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Ingår i: Molecular and Cellular Probes. - : Elsevier BV. - 0890-8508 .- 1096-1194. ; 13:1, s. 49-60
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Tidskriftsartikel (refereegranskat)abstract
- A seminested polymerase chain reaction (PCR)-based diagnostic assay was evaluated for detection and verification of Neisseria meningitidis, Haemophilus influenzae, Streptococcus pneumoniae, Steptococcus agalactiae and Listeria monocytogenes in cerebrospinal fluid (CSF) and other biological samples. A general bacterial amplicon from the 16S rRNA gene was amplified in a first step, and species-specific regions in a second. The detection level was 4 fg DNA/reaction, corresponding to about one bacterial genome per reaction tube. Sample preparations (Dynabeads DNA DIRECT kit) were assayed from 140 bacterial strains suspended in saline. In CSF the detection level for bacteria was 103 CFU ml-1 for N. meningitidis, H. influenzae and S. pneumoniae, 104 CFU ml-1 for Escherichia coli and 105 CFU ml-1 for S. agalactiae and L. monocytogenes. The detection levels for these bacteria were the same in the other tested biological samples, like blood with or without culture media. Clinical CSF samples were evaluated from 71 patients with proven bacterial meningitis, as were 61 CSF samples from individuals without bacterial meningitis. The diagnostic sensitivity of the assay in detecting bacteria in general was 0.97, and for the specific species in the clinical CSF samples 0.87-0.94. The specificity was 1.0 for detecting bacteria in general. Some cross-reactions were noted within the streptococcus group. The PCR results were verified by banding patterns of HaeIII digested PCR products.
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| 2. |
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| 3. |
- Erlandsson, Ann, 1968-, et al.
(författare)
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Quantification of Bordetella pertussis in clinical samples by colorimetric detection of competitive PCR products
- 1998
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Ingår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - : John Wiley & Sons. - 0903-4641 .- 1600-0463. ; 106:7-12, s. 1041-1048
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Tidskriftsartikel (refereegranskat)abstract
- Quantification of microorganisms is an important part of the normal diagnostic work of a clinical microbiology laboratory. Traditionally the diagnosis of pertussis is subject to a yes or no approach with no quantitative dimension. This can, however, be of interest as a factor when judging the risk of a patient spreading the bacterium and as a research tool. The aim of the present study was to develop a PCR-based quantitative assay for Bordetella pertussis DNA in clinical nasopharyngeal aspirates by combining a quantitative PCR with a colorimetric detection principle, DIANA (detection of immobilised amplified nucleic acid). A competitor to the PCR target sequence in IS-481, containing a lac-operator, was constructed and calibrated, and a test protocol prepared. A total of 46 clinical nasopharyngeal aspirates, previously diagnosed using a standard nested PCR assay and quantified by culture, were analysed by the quantitative PCR. The method showed acceptable precision and accuracy considering that it estimates the total number of bacterial genomes while culture detects viable bacteria. Recognised advantages were the simple colorimetric detection, the inborn indication of a working PCR assay, and the possibility of obtaining results even when partial inhibition of the PCR assay was seen. In addition, the quantitative PCR result can be obtained within one day compared to 3–10 days for culture. The present results and the qualities of the quantitative PCR suggest that this assay will be a useful complement in routine diagnostics and in research.
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| 4. |
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| 5. |
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| 6. |
- Garpenholt, Örjan, et al.
(författare)
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The impact of Haemophilus influenzae type b vaccination in Sweden
- 1996
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Ingår i: Scandinavian Journal of Infectious Diseases. - 0036-5548 .- 1651-1980. ; 28:2, s. 165-169
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Tidskriftsartikel (refereegranskat)abstract
- The number of patients with meningitis and bacteremia due to Haemophilus influenzae was studied in Sweden over the period 1987-1994. Conjugated H. influenzae type b vaccines were introduced in Sweden in 1992, and all children born after December 31, 1992, were offered vaccination free of charge. A rapid decline of H. influenzae meningitis and bacteraemia was observed in the autumn of 1993, when the expected peak incidence failed to appear. In the prevaccination period 1987-1991, the average annual incidence (cases/100,000) was 34.4 in children aged 0-4 years. In 1994, the annual incidence fell to 3.5. No significant decline was observed in older children or adults. There was a 92% reduction in the number of meningitis cases and an 83% reduction in cases of bacteraemia. A similar decline was noted in 2 regions which followed different strategies for the introduction of the vaccination programme.
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| 7. |
- Hugosson, Svante, et al.
(författare)
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Invasive Haemophilus influenzae Disease : Epidemiology and Clinical Spectrum Before Large-scale H. influenzae Type b Vaccination
- 1995
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Ingår i: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 0036-5548 .- 1651-1980. ; 27:1, s. 63-67
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Tidskriftsartikel (refereegranskat)abstract
- In a prospective study between January 1987 and December 1992, 103 patients with invasive Haemophilus influenzae (Hi) infection were identified in a well-defined population before large-scale Haemophilus influenzae type b (Hib) vaccination was introduced. The incidence (cases/100,000/year) of invasive Hi infection was 5.9 for the whole population, 55 for children 0-4 years old and as high as 2.8 for adults. Hib was the predominant cause of the infection (83 cases) in children but, in adults, 13/39 (30%) cases were caused by non-typable Hi and 6/39 (19%) by Hi serotype f. Three patients (3%) died and 6 (5.8%) suffered a permanent sequel from the infection. All patients with such a sequel had invasive Hib infection. No significant difference between patients 0-6 years old and matched controls regarding the frequency of subnormal serum levels of immunoglobulins was found.
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| 8. |
- Norda, Rut, et al.
(författare)
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Transmission of hepatitis C virus by transfusion in Orebro County, Sweden, 1990-1992
- 1995
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Ingår i: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 0036-5548 .- 1651-1980. ; 27:5, s. 449-452
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Tidskriftsartikel (refereegranskat)abstract
- A retrospective study of hepatitis C virus (HCV) transmission by transfusion was conducted in Orebro county. Out of the 7,900 active, registered blood donors, 21 repeatedly anti-HCV reactive (RIVA 2 positive or indeterminate) donors were diagnosed. Their 84 recipients from January 1990 through June 1992 were identified and 41 (49%) were alive in December 1992. A total of 13 anti-HCV reactive (RIBA 2 positive or indeterminate) were diagnosed in 39 investigated recipients. Of these 11 were previously undiagnosed, and seven were HCV RNA-positive. In the donor population 1.03% were anti-HCV-positive by ELISA, but only 0.09% were RIBA and HCV RNA-positive. In 1990, 0.06% of the blood components came from the HCV RNA-positive donors, and none during the first 6 months of 1992. In order to identify transfusion-transmitted HCV infections that took place before the introduction of tests for anti-HCV antibodies, patients with a history of transfusion and symptoms and signs of liver dysfunction or damage should be thoroughly tested.
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| 9. |
- Orvelid, Paula, et al.
(författare)
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PCR Identification of the Group A Neisseria Meningitidis Gene in Cerebrospinal Fluid
- 1999
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Ingår i: Scandinavian Journal of Infectious Diseases. - : Informa UK Limited. - 0036-5548 .- 1651-1980. ; 31:5, s. 481-483
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to develop a PCR method for direct identification of Neisseria meningitidis serogroup A in cerebrospinal fluid. The assay makes use of unique sites within the gene cassette responsible for expression of the (α1→6)-linked N-acetyl-D-mannosamine-1-phosphate serogroup A capsule. A total of 67 different N. meningitidis strains and 12 clinical samples of CSF, culture positive for N. meningitidis, were examined. All the strains and samples of N. meningitidis serogroup A were correctly identified by an amplified PCR product of 519 bp. The PCR method for identification is specific for the group A gene of N. meningitidis. The assay may contribute to reducing recurrent, devastating epidemics of meningococcal infection by providing a diagnostic tool for grouping in developing countries where problems with false negative cultures are common and vaccination against serogroup A meningococci may be required.
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| 10. |
- Silfverdal, Sven Arne, et al.
(författare)
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Protective effect of breastfeeding : an ecologic study of Haemophilus influenzae meningitis and breastfeeding in a Swedish population
- 1999
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Ingår i: International Journal of Epidemiology. - : Oxford University Press (OUP). - 0300-5771 .- 1464-3685. ; 28:1, s. 152-156
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: In Orebro County, Sweden, a 2.5-fold increase in the incidence of Haemophilus influenzae (HI) meningitis was found between 1970 and 1980. In a case-control study of possible risk factors for invasive HI infection conducted in the same area, 1987-1992, breastfeeding was found to be a strong protective factor. MATERIAL AND METHODS: In order to study the relation between incidence rates of HI meningitis between 1956-1992 and breastfeeding rates in the population an ecologic study was performed. RESULTS: A strong (negative) correlation between breastfeeding and incidence of HI infection 5 to 10 years later (rho(xy) (s) approximately -0.6) was seen, whereas no relation seems to exist for the time lag 15 years and beyond. The correlation for contemporary data was intermediate. There were similar results for the breastfeeding proportions at 2, 4 as well as 6 months of age. DISCUSSION: Our ecologic data are consistent with results from our case-control study. The time-lag for the delayed effect on the population level could be estimated although sparse data make the estimates vulnerable to sampling fluctuations. Limitations with ecologic studies are discussed. CONCLUSION: There seems to be an association between high breastfeeding rate in the population and a reduced incidence of HI meningitis 5 to 10 years later. These results do have implications on strategies for breastfeeding promotion, especially in countries where Hib vaccination is too costly and not yet implemented.
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