Frequency of 530‐bp deletion in <i>Actinobacillus actinomycetemcomitans</i> leukotoxin promoter region

Contreras, A; Rusitanonta, T.; Chen, C.; Wagner, Wilma; Michalowicz, Bryan S.; Slots, Jørgen

doi:10.1034/j.1399-302x.2000.150513.x

Cited by 46 publications

(50 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…All highly leukotoxic strains were serotype b, but two serotype b reference strains (ATCC 29524 and Y4) contained the minimally leukotoxic promoter. It has been shown that highly leukotoxic strains of A. actinomycetemcomitans are frequently isolated from LJP patients (12,14), Africans and African-Americans (3,12), and younger subjects (12). In our study, highly leukotoxic strains comprised 25% of the isolates from LJP patients (5 of 20) and 25% of the isolates from healthy subjects (1 of 4).…”

Section: Resultsmentioning

confidence: 77%

“…Highly leukotoxic strains also comprise approximately one-half of the strains isolated from Africans and African-Americans but only 0 to 2% of strains isolated from Europeans and Asians (3,12,14,15). These findings led to the hypothesis that LJP may have two different etiologies and epidemiologies: in Caucasians LJP may be associated with diverse A. actinomycetemcomitans clones acting as opportunistic pathogens, whereas in some Africans and African-Americans LJP may be associated with JP2-like strains acting as exogenous pathogens (23).…”

Section: Discussionmentioning

confidence: 99%

“…For example, studies on the distribution of A. actinomycetemcomitans serotype a to e strains showed that serotype a and b strains are frequently isolated from LJP patients, serotype c strains are more common in nonoral infections and in healthy people, and serotype d and e strains are rare in all populations (1,15,28,43). Studies on the leukotoxin gene showed that strains carrying a 530-bp deletion in the leukotoxin gene promoter that results in 10-to 20-fold-higher levels of leukotoxin production are almost exclusively isolated from LJP patients, suggesting that these strains may have an increased virulence potential (3,12,(14)(15)(16). Other studies have shown an association between disease and certain restriction fragment length polymorphism genotypes (6) or arbitrarily primed PCR (AP-PCR) genotypes (1,28).…”

mentioning

confidence: 99%

See 2 more Smart Citations

Population Structure and Genetic Diversity of Actinobacillus actinomycetemcomitans Strains Isolated from Localized Juvenile Periodontitis Patients

et al. 2002

View full text Add to dashboard Cite

The phylogeny of 20 Actinobacillus actinomycetemcomitans strains isolated from patients with localized juvenile periodontitis (LJP) was investigated by using partial sequence analysis of 16S rRNA genes, arbitrarily primed PCR (AP-PCR), and four additional PCR assays that amplified polymorphic regions in the leukotoxin (lkt), cytolethal distending toxin (cdt), major fimbrial subunit (flp-1), and serotype-specific O polysaccharide gene clusters. Our analysis also included four strains isolated from healthy subjects and nine reference strains. We found that A. actinomycetemcomitans strains comprised three major phylogenetic lineages. One lineage consisted of serotype b strains, a second lineage consisted of serotype c strains, and a third lineage consisted of serotype a, d, e, and f strains. 16S rRNA sequences within each lineage were highly conserved (<1% base substitutions), whereas sequences between lineages were exceptionally divergent (1.9 to 5.0% substitutions). Two strains exhibited 16S rRNA sequences that were even more distantly related to those of the three major lineages (2.7 to 6.7% substitutions), indicating that additional minor lineages or variants exist. The distribution of 16S rRNA sequences and lkt, cdt, flp-1, and AP-PCR genotypes was consistent with a clonal population structure, with little evidence of assortative recombination between strains of different serotypes. Strains from all three major lineages were recovered from LJP patients, suggesting that phylogenetically diverse strains of A. actinomycetemcomitans carry pathogenic potential.

show abstract

Section: Resultsmentioning

confidence: 77%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Population Structure and Genetic Diversity of Actinobacillus actinomycetemcomitans Strains Isolated from Localized Juvenile Periodontitis Patients

et al. 2002

View full text Add to dashboard Cite

show abstract

“…Microorganisms produce several virulence factors that could be involved in the destruction of periodontal tissues. The most important one seems to be leukotoxic activity (46,47) . The highly leukotoxic bacterial strains of Aa (strain JP2) can produce 10 to 20 times more toxins than other strains, giving them the potential to interfere with innate immune host defenses (48) .…”

Section: Microbiologymentioning

confidence: 99%

Diagnóstico y tratamiento de la periodontitis agresiva

Benza-Bedoya

Pareja-Vásquez

2017

Odontoestomatología

View full text Add to dashboard Cite

Aggressive periodontitis is a low-prevalence, multifactorial disease, of rapid progression and with no systemic compromise. It presents immunological alterations, a strong genetic influence, familial aggregation and early onset. It can be localized or generalized. It is not clear whether it is an independent periodontal disease, or if it is the phenotypic expression of chronic periodontitis in susceptible patients. Its diagnostic protocol includes a dental medical history, a clinical periodontal examination and a radiological examination. Treatment usually includes improving oral hygiene, dental scaling and root planing, as well as systemic and local antibiotic therapy. Surgical therapy will depend on each individual case. Maintenance therapy is essential to achieve better results. The aim of this paper is to review diagnostic and therapeutic protocols, and to propose a treatment flowchart based on the latest scientific evidence.

show abstract

“…Members of a particular clonal lineage (JP2) of A. actinomycetemcomitans (18) show a unique 530-bp deletion (⌬530) in the promoter region of the ltx operon resulting in enhanced production of leukotoxin, a key virulence factor (1). The JP2 clone shows marked racial tropism as it has been isolated almost exclusively from adolescent periodontitis patients of West and Northwest African descent, including both Africans and Arabs (2,3,4,5,6). Substantial evidence shows that the JP2 clone induces aggressive periodontitis in these populations and constitutes a particularly pathogenic subpopulation of A. actinomycetemcomitans (see reference 6a); reviewed in reference 8).…”

mentioning

confidence: 99%

Novel Loop-Mediated Isothermal Amplification Method for Detection of the JP2 Clone of Aggregatibacter actinomycetemcomitans in Subgingival Plaque

et al. 2008

View full text Add to dashboard Cite

We developed a loop-mediated isothermal amplification method that detects the JP2 clone of Aggregatibacter actinomycetemcomitans, which induces aggressive periodontitis in adolescents of North and West African descents. Being independent of special equipment, this specific and sensitive method offers significant advantages for screening of patients on a population basis and in clinical settings.Aggregatibacter (Actinobacillus) actinomycetemcomitans (11) has long been suspected as an etiological factor in periodontitis in juveniles (17,19). Members of a particular clonal lineage (JP2) of A. actinomycetemcomitans (18) show a unique 530-bp deletion (⌬530) in the promoter region of the ltx operon resulting in enhanced production of leukotoxin, a key virulence factor (1). The JP2 clone shows marked racial tropism as it has been isolated almost exclusively from adolescent periodontitis patients of West and Northwest African descent, including both Africans and Arabs (2,3,4,5,6). Substantial evidence shows that the JP2 clone induces aggressive periodontitis in these populations and constitutes a particularly pathogenic subpopulation of A. actinomycetemcomitans (see reference 6a); reviewed in reference 8).Because the presence of the JP2 clone has significant implications for prevention and treatment of periodontitis in juveniles, it is essential to be able to accurately determine its presence in subgingival plaque samples. Cultivation by itself does not distinguish between the JP2 clone and other genotypes of the species. PCR detection of the ⌬530 deletion has been used to identify the JP2 clone in plaque samples and among isolates and to distinguish it from other A. actinomycetemcomitans strains (13,15,20). However, there is a need for a simple and low-technology method for detection of the JP2 clone. For that purpose, the loop-mediated isothermal amplification (LAMP) method is an attractive alternative to conventional PCR (12).The LAMP reaction runs at a constant temperature, usually around 65°C, and uses four primers that recognize six distinct regions of the target DNA, combined with the Bst DNA polymerase large fragment, which has strand displacement activity and is heat inactivated at 80°C (12). The reaction can be accelerated by inclusion of additional loop primers (10). The resulting amplification products are a complex mixture of stem-loop DNAs with inverted repeats and cauliflower-like structures (12) and induce a white precipitate of magnesium pyrophosphate proportional to the amount of amplified DNA and visible to the naked eye (9). Usually, LAMP primers are designed to specifically recognize a target sequence that is unique to the microorganism in question. A LAMP method targeting the dam gene, which is common to all members of A. actinomycetemcomitans, was reported recently (14). We wanted to develop a method that specifically detects the JP2 clone and took advantage of the specific ⌬530 deletion. The low percentage of GϩC in the sequence around ⌬530 made it impossible to design appropriate LAMP primers in...

show abstract

Frequency of 530‐bp deletion in Actinobacillus actinomycetemcomitans leukotoxin promoter region

Cited by 46 publications

References 19 publications

Population Structure and Genetic Diversity of Actinobacillus actinomycetemcomitans Strains Isolated from Localized Juvenile Periodontitis Patients

Population Structure and Genetic Diversity of Actinobacillus actinomycetemcomitans Strains Isolated from Localized Juvenile Periodontitis Patients

Diagnóstico y tratamiento de la periodontitis agresiva

Novel Loop-Mediated Isothermal Amplification Method for Detection of the JP2 Clone of Aggregatibacter actinomycetemcomitans in Subgingival Plaque

Contact Info

Product

Resources

About