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  • Claesson, Rolf  (6)
  • 2020-2024  (6)
  • 1
    Online Resource
    Online Resource
    DataSheet_1.pdf
    Frontiers Media SA ; 2021
    In:  Frontiers in Cellular and Infection Microbiology Vol. 11 ( 2021-12-14)
    Details
    In: Frontiers in Cellular and Infection Microbiology, Frontiers Media SA, Vol. 11 ( 2021-12-14)
    Abstract: The Gram-negative bacterium, Aggregatibacter actinomycetemcomitans is associated with periodontitis affecting young individuals. The geographic dissemination of the highly leukotoxic JP2 genotype of serotype b of this species was previously studied by multilocus sequence typing (MLST). Here, we have used MLST to genetically characterize non-JP2 genotype strains of serotype b, isolated from individuals living in Ghana (n=41), and in Sweden (n=13), respectively. Results The MLST analysis revealed a total of nine sequence types (ST). Both Ghanaian and Swedish isolates were distributed in ST 1-3. ST 5 and 6 were only identified among the Ghanaian strains, whereas ST 4, 7, 8 and 9 were uniquely represented among the Swedish strains. Previously, we characterized these non-JP2 genotype strains of A. actinomycetemcomitans serotype b by arbitrarily-primed (AP)-PCR, which distributed them into three groups, AP-PCR type 1, 2, and 3, respectively. AP-PCR type 1 strains are generally highly leukotoxic, and are associated with progression of periodontal attachment loss. As AP-PCR type 1 includes both JP2 genotype strains and a proportion of non-JP2 genotype strains of serotype b, a straightforward diagnostic procedure has been sought. This has revealed a gene, cagE , which appears to be conserved only in this AP-PCR type. According to our results, MLST was not a highly discriminatory method to identify AP-PCR type 1, as strains of this AP-PCR type could be found within three different ST: ST 2, ST 3 and ST 8. Conclusion According to MLST, a geographic dissemination of non-JP2 genotype A. actinomycetemcomitans serotype b appears to exist. However, aiming to identify carriers of AP-PCR type 1, non-JP2 genotype serotype b, PCR with cagE -specific primers is likely the most efficient diagnostic procedure known today.
    Type of Medium: Online Resource
    ISSN: 2235-2988
    URL: Article
    URL: Article
    DOI: 10.3389/fcimb.2021.769671
    DOI: 10.3389/fcimb.2021.769671.s001
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2021
    detail.hit.zdb_id: 2619676-1
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  • 2
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    Discrepancies in Antimicrobial Susceptibility between the JP2 and the Non-JP2 Genotype of Aggregatibacter actinomycetemcomitans
    MDPI AG ; 2022
    In:  Antibiotics Vol. 11, No. 3 ( 2022-02-27), p. 317-
    Details
    In: Antibiotics, MDPI AG, Vol. 11, No. 3 ( 2022-02-27), p. 317-
    Abstract: The Aggregatibacter actinomycetemcomitans JP2 genotype is associated with high leukotoxin production and severe (aggressive) periodontitis. The aim of this study was to compare the antimicrobial susceptibility of JP2 and non-JP2 genotype strains. Minimal inhibitory concentrations (MICs) of 11 antimicrobials were determined for 160 A. actinomycetemcomitans of serotype a, b, or c, mostly isolated in Sweden or Ghana. MIC distributions for benzylpenicillin and fusidic acid revealed a more susceptible subpopulation for 38 serotype b strains, including the 32 of the JP2 genotype, with a benzylpenicillin MIC range of 0.125–0.5 mg/L. In contrast, benzylpenicillin MIC ≤ 16 mg/L was the estimated 99.5% epidemiological cutoff (ECOFF) of all strains. Beta-lactamase production was not detected. The fusidic acid MIC distribution of 11 strains of Aggregatibacter aphrophilus agreed with that found in non-JP2 strains. Cefotaxime, meropenem, levofloxacin, and trimethoprim–sulfamethoxazole MICs were all ≤0.25 mg/L, while MIC90 values for amoxicillin, azithromycin and tetracycline were 1 mg/L. Metronidazole MICs varied between 0.5 and 〉 256 mg/L. The discrepant findings indicate that A. actinomycetemcomitans may be divided into two separate wild types, with a suggested intrinsic reduced susceptibility for benzylpenicillin in the majority of non-JP2 genotype strains. Possible implications for the treatment of A. actinomycetemcomitans infections are discussed.
    Type of Medium: Online Resource
    ISSN: 2079-6382
    URL: Article
    DOI: 10.3390/antibiotics11030317
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2681345-2
    SSG: 15,3
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  • 3
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    Characterization of Aggregatibacter actinomycetemcomitans Serotype b Strains with Five Different, Including Two Novel, Leukotoxin Promoter Structures
    MDPI AG ; 2020
    In:  Vaccines Vol. 8, No. 3 ( 2020-07-20), p. 398-
    Details
    In: Vaccines, MDPI AG, Vol. 8, No. 3 ( 2020-07-20), p. 398-
    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.
    Type of Medium: Online Resource
    ISSN: 2076-393X
    URL: Article
    DOI: 10.3390/vaccines8030398
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2703319-3
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  • 4
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    Aggregatibacter actinomycetemcomitans and Filifactor alocis as Associated with Periodontal Attachment Loss in a Cohort of Ghanaian Adolescents
    MDPI AG ; 2022
    In:  Microorganisms Vol. 10, No. 12 ( 2022-12-19), p. 2511-
    Details
    In: Microorganisms, MDPI AG, Vol. 10, No. 12 ( 2022-12-19), p. 2511-
    Abstract: The aims of the present study were to document the presence of Aggregatibacter actinomyctemcomitans and the emerging oral pathogen Filifactor alocis, as well as to identify genotypes of these bacterial species with enhanced virulence. In addition, these data were analyzed in relation to periodontal pocket depth (PPD) and the progression of PPD from the sampled periodontal sites during a two-year period. Subgingival plaque samples were collected from 172 periodontal pockets of 68 Ghanaian adolescents. PPD at sampling varied from 3–14 mm and the progression from baseline, i.e., two years earlier up to 8 mm. The levels of A. actinomycetemcomitans and F. alocis were determined with quantitative PCR. The highly leukotoxic JP2-genotype of A. actinomycetemcomitans and the ftxA a gene of F. alocis, encoding a putative Repeats-in-Toxin (RTX) protein, were detected with conventional PCR. The prevalence of A. actinomycetemcomitans was 57%, and 14% of the samples contained the JP2 genotype. F. alocis was detected in 92% of the samples and the ftxA gene in 52%. The levels of these bacterial species were significantly associated with enhanced PPD and progression, with a more pronounced impact in sites positive for the JP2 genotype or the ftxA gene. Taken together, the results indicate that the presence of both A. actinomycetemcomitans and F. alocis with their RTX proteins are linked to increased PPD and progression of disease.
    Type of Medium: Online Resource
    ISSN: 2076-2607
    URL: Article
    DOI: 10.3390/microorganisms10122511
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2720891-6
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  • 5
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    Radiographic and clinical signs of periodontitis and associated bacterial species in a Swedish adolescent population
    Wiley ; 2023
    In:  Journal of Periodontology Vol. 94, No. 5 ( 2023-05), p. 630-640
    Details
    In: Journal of Periodontology, Wiley, Vol. 94, No. 5 ( 2023-05), p. 630-640
    Abstract: Periodontitis in adolescents has historically been rare in the Nordic countries but could be expected to increase due to changing 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, between controls without bone loss and cases with bone loss. Methods Adolescents born in 2001 who had a dental examination in 2016 ( n  = 1656) were screened for proximal bone loss using bitewing radiographs taken during dental examinations (2014–2016). Individuals exhibiting 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 examined by quantitative PCR. The subgingival plaque samples were also analyzed via cultivation technique. Results Proximal bone loss was identified in 24 individuals (1.45%) based on 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 is increasing among adolescents in Sweden because of demographic differences (an increasingly heterogenous population), and emphasize the importance of radiographs for early detection of this disease.
    Type of Medium: Online Resource
    ISSN: 0022-3492 , 1943-3670
    URL: Issue
    URL: Article
    DOI: 10.1002/jper.v94.5
    DOI: 10.1002/JPER.22-0453
    Language: English
    Publisher: Wiley
    Publication Date: 2023
    detail.hit.zdb_id: 2040047-0
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  • 6
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    Online Resource
    Association of Filifactor alocis and its RTX toxin gene ftxA with periodontal attachment loss, and in synergy with Aggregatibacter actinomycetemcomitans
    Frontiers Media SA ; 2024
    In:  Frontiers in Cellular and Infection Microbiology Vol. 14 ( 2024-3-26)
    Details
    In: Frontiers in Cellular and Infection Microbiology, Frontiers Media SA, Vol. 14 ( 2024-3-26)
    Abstract: The Gram-positive bacterium, Filifactor alocis is an oral pathogen, and approximately 50% of known strains encode a recently identified repeat-in-toxin (RTX) protein, FtxA. By assessing a longitudinal Ghanaian study population of adolescents (10-19 years of age; mean age 13.2 years), we recently discovered a possible correlation between deep periodontal pockets measured at the two-year follow-up, presence of the ftxA gene, and a high quantity of F. alocis . To further understand the contribution of F. alocis and FtxA in periodontal disease, we used qPCR in the present study to assess the carriage loads of F. alocis and the prevalence of its ftxA gene in subgingival plaque specimens, sampled at baseline from the Ghanaian cohort (n=500). Comparing these results with the recorded clinical attachment loss (CAL) longitudinal progression data from the two-year follow up, we concluded that carriers of ftxA -positive F. alocis typically exhibited higher loads of the bacterium. Moreover, high carriage loads of F. alocis and concomitant presence of the ftxA gene were two factors that were both associated with an enhanced prevalence of CAL progression. Interestingly, CAL progression appeared to be further promoted upon the simultaneous presence of F. alocis and the non-JP2 genotype of Aggregatibacter actinomycetemcomitans . Taken together, our present findings are consistent with the notion that F. alocis and its ftxA gene promotes CAL during periodontal disease.
    Type of Medium: Online Resource
    ISSN: 2235-2988
    URL: Article
    DOI: 10.3389/fcimb.2024.1376358
    Language: Unknown
    Publisher: Frontiers Media SA
    Publication Date: 2024
    detail.hit.zdb_id: 2619676-1
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