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| 2. |
- Alestig, Erik, et al.
(författare)
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Phylogenetic origin of hepatitis B virus strains with precore C-1858 variant.
- 2001
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Ingår i: Journal of clinical microbiology. - 0095-1137. ; 39:9, s. 3200-3
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Tidskriftsartikel (refereegranskat)abstract
- Mutations that prevent the expression of the hepatitis B e antigen frequently emerge in the immunoreactive phase of infection. The predominant mutation, the precore G-->A-1896 mutation, is restricted by the variability at position 1858 and is rare in strains with cytosine at nucleotide 1858. The C-1858 variant is characteristic of genotype A. It also occurs in genotypes C and F, but not in B, D, or E, explaining the geographical variation in the prevalence of precore mutants. C-1858 strains have been frequently observed in southeast Asia, but have not been phylogenetically characterized. By sequencing eight complete hepatitis B virus genomes, C-1858 variants of east Asian origin were found to constitute a phylogenetic entity within genotype C that probably diverged several hundred years ago. Further study of the distribution of this variant is warranted.
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| 3. |
- Allard, A, et al.
(författare)
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Rapid typing of human adenoviruses by a general PCR combined with restriction endonuclease analysis.
- 2001
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 39:2, s. 498-505
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Tidskriftsartikel (refereegranskat)abstract
- We have developed a system for rapid typing of adenoviruses (Ads) based on a combination of PCR and restriction endonuclease (RE) digestion (PCR-RE digestion). Degenerated consensus primers were designed, allowing amplification of DNA from all 51 human Ad prototype strains and altogether 44 different genome variants of Ad serotypes 1, 3, 4, 5, 7, 11, 19, 40, and 41. The 301-bp amplimer of 22 prototype strains representing all six subgenera and the genome variant was selected as a target for sequencing to look for subgenus and genome type variabilities. The sequences obtained were used to facilitate the selection of specific REs for discrimination purposes in a diagnostic assay by following the concept of cleavage or noncleavage of the 301-bp amplimer. On the basis of these results, a flowchart was constructed, allowing identification of subgenus B:2 and D serotypes and almost complete distinction of subgenus A, B:1, C, E, and F serotypes. Application of the PCR-RE digestion system to clinical samples allowed typing of 34 of 40 clinical samples positive for Ad. The genome type determined by this method was identical to that obtained by traditional RE typing of full-length Ad DNA. The remaining six samples were positive only after a nested PCR. Therefore, to reduce the risk of false-negative results, samples scored negative by the PCR-RE digestion system should be evaluated by the described nested PCR. Used in combination, the PCR-RE digestion method and the nested PCR provide a reliable and sensitive system that can easily be applied to all kinds of clinical samples when rapid identification of adenoviruses is needed.
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| 6. |
- Aspevall, O, et al.
(författare)
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Performance of four chromogenic urine culture media after one or two days of incubation compared with reference media.
- 2002
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 40, s. 1500-1503
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Tidskriftsartikel (refereegranskat)abstract
- Four chromogenic urine culture media were compared to culture on blood agar, MacConkey agar, and CLED (cysteine-, lactose-, and electrolyte-deficient) agar for detection of uropathogens in 1,200 urine specimens. After 2 nights of incubation, 96% of all isolates were recovered on blood agar, 96% were recovered on CLED agar, 92% were recovered on CPS ID2, 96% were recovered on CHROMagar Orientation from BBL, 95% were recovered on CHROMagar Orientation from The CHROMagar Company, and 95% were recovered on Chromogenic UTI Medium.
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| 10. |
- Broman, T., et al.
(författare)
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Campylobacter jejuni in black-headed gulls (Larus ridibundus) : prevalence, genotypes, and influence on C. jejuni epidemiology
- 2002
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Ingår i: Journal of Clinical Microbiology. - 0095-1137 .- 1098-660X. ; 40:12, s. 4594-4602
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Tidskriftsartikel (refereegranskat)abstract
- Campylobacteriosis is a zoonotic disease in which birds have been suggested to play an important role as a reservoir. We investigated the prevalence of Campylobacter jejuni subsp. jejuni in black-headed gulls (Larus ridibundus) in southern Sweden with the aim of examining the nature of C. jejuni infection in this bird species. Birds were sampled in four sampling series each year during 1999 (n = 419) and 2000 (n = 365). Longitudinally sampled C. jejuni isolates from individual gulls were subjected to macrorestriction profiling (MRP) by pulsed-field gel electrophoresis to investigate the genotypical stability during the natural course of infection. Furthermore, a subset (n = 76) of black-headed gull isolates was compared to isolates from broiler chickens (n = 38) and humans (n = 56) originating from the same geographic area. We found a pronounced seasonal variation in C. jejuni carriage, with the highest rates found in late autumn. MRP similarities were higher between isolates of human and broiler chicken origin, than between those of wild bird origin and either of the other two hosts. However, identical MRPs were found in two gull isolates and one human isolate after digestion with two restriction enzymes, strongly indicating that they may have been colonized by the same clone of C. jejuni. The MRPs most prevalent in gull isolates did not occur among isolates from humans and broiler chickens, suggesting the existence of a subpopulation of C. jejuni adapted to species-specific colonization or environmental survival.
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