| 1. |
- Claesson, Rolf, et al.
(författare)
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Characterization of Aggregatibacter actinomycetemcomitans Serotype b Strains with Five Different, Including Two Novel, Leukotoxin Promoter Structures
- 2020
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Ingår i: Vaccines. - Basel, Switzerland : MDPI. - 2076-393X. ; 8:3
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Tidskriftsartikel (refereegranskat)abstract
- The JP2 genotype of A. actinomycetemcomitans, serotype b has attracted much interest during the past three decades due to its close association with periodontitis in young individuals and the enhanced expression of a leukotoxin (LtxA). A typical feature of this genotype is a 530-base pair (bp) deletion in the ltxCABD promoter region controlling leukotoxin expression. In the present work, we have characterized serotype b strains with four additional promoter types. Two novel types have been recognized, that is, one with a 230-bp deletion and one with a 172-bp duplication. Moreover, a strain with a 640-bp deletion and three strains with a full-length promoter, including the type strain Y4, were included in the present study. The seven strains were characterized by multi locus sequence typing (MLST) and arbitrarily primed polymerase chain reaction (PCR) and assessed for LtxA production. MLST showed that the strains with the non-JP2-like deletions represented distinct monophyletic groups, whereas the JP2 strain, HK1651, represented a separate branch. LtxA production was high in all three strains with a promoter deletion, whereas the other four strains showed significantly lower levels. It can be concluded that the genetic characterization and determination of LtxA production of A. actinomycetemcomitans isolates from individuals with periodontitis can contribute to the identification of novel virulent genotypes of this bacterium.
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| 2. |
- Lindholm, Mark, et al.
(författare)
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Radiographic and clinical signs of periodontitis and associated bacterial species in a Swedish adolescent population
- 2023
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Ingår i: Journal of Periodontology. - : John Wiley & Sons. - 0022-3492 .- 1943-3670. ; 94:5, s. 630-640
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Tidskriftsartikel (refereegranskat)abstract
- Background: Periodontitis in adolescents has historically been rare in the Nordic countries but could be expected to increase due to changes in demographics. The primary aim was to cross-sectionally examine the presence of radiographic bone loss in adolescents in Västerbotten County, Sweden. The secondary aim was to compare periodontal and microbial parameters, as well as demographic patterns, in controls without bone loss with cases with bone loss.Methods: Adolescents born 2001 and who had a dental examination 2016 (n = 1656) were screened for proximal bone loss using bitewing radiographs taken during dental examinations (2014-2016). Individuals that exhibited proximal bone loss (> 2 mm) were invited to participate in a complete periodontal examination. Subgingival plaque and saliva were also sampled. For each adolescent with bone loss, two healthy individuals as controls were examined. Selected bacterial species in saliva and subgingival plaque were quantitatively examined by quantitative PCR. The subgingival plaque samples were also analysed with cultivation technique.Results: Proximal bone loss was identified in 24 individuals (1.45%) based on all the radiographs. Thirteen of these cases were periodontally examined and matched with 26 controls. Most cases were diagnosed with periodontitis (12/13 [92%]), whereas none of the controls had periodontitis. Higher concentrations and higher prevalence of the bacteria Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Filifactor alocis were generally found in the cases.Conclusion:The results suggest that periodontitis among adolescents, because of demographic differences (an increasingly heterogenous population), in Sweden is increasing and emphasizes the importance of radiographs for early detection of this disease.
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