Rapid identification of Actinobacillus actinomycetemcomitans based on analysis of 23S ribosomal RNA

Complete Genome Sequence of Aggregatibacter actinomycetemcomitans Strain CU1000N

Here, we report the complete genome sequence of Aggregatibacter actinomycetemcomitans strain CU1000N. This rough strain is used extensively as a model organism to characterize localized aggressive periodontitis pathogenesis, the basic biology and oral cavity colonization of A. actinomycetemcomitans, and its interactions with other members of the oral microbiome.

Complete Genome Sequence of Aggregatibacter actinomycetemcomitans Strain IDH781

We report here the complete genomic sequence and methylome of Aggregatibacter actinomycetemcomitans strain IDH781. This rough strain is used extensively as a model organism to characterize localized aggressive periodontitis pathogenesis, the basic biology and oral cavity colonization of A. actinomycetemcomitans, and its interactions with other members of the oral microbiome.

Evaluation of two commercial kits and arbitrarily primed PCR for identification and differentiation of Actinobacillus actinomycetemcomitans, Haemophilus aphrophilus, and Haemophilus paraphrophilus

The closely related species Actinobacillus actinomycetemcomitans, Haemophilus aphrophilus, and Haemophilus paraphrophilus are common findings in oral microbiota. The aims of this study were to evaluate the applicability of the Rapid NH and API ZYM kits and arbitrarily primed PCR (AP-PCR) in the identification and differentiation of the three species from each other. The material included 62 clinical isolates and three reference strains of A. actinomycetemcomitans representing the 5 serotypes and 18 AP-PCR genotypes. Haemophilus species included 12 clinical isolates and 11 reference strains of H. aphrophilus, H. paraphrophilus, and 5 other species. For the PCR amplification, the oligonucleotide 5'-CAGCACCCAC-3' was used as a primer. Contrary to the consistent performance of API ZYM, the Rapid NH system was able to identify only 10 of 65 (15%) A. actinomycetemcomitans isolates, whereas all Haemophilus species were correctly identified. The API ZYM test differentiated A. actinomycetemcomitans from H. aphrophilus and H. paraphrophilus by negative beta-galactosidase and alpha-glucosidase reactions and a positive esterase lipase reaction. However, the API ZYM test was unable to differentiate H. aphrophilus from H. paraphrophilus, it also could not differentiate A. actinomycetemcomitans serotypes from each other. Among the H. aphrophilus isolates three AP-PCR genotypes and among H. paraphrophilus isolates only one AP-PCR genotype, distinct from those of A. actinomycetemcomitans, were found. The Rapid NH test showed poor ability to identify clinical isolates of all A. actinomycetemcomitans serotypes. Moreover, AP-PCR genotyping proved to be a rapid method for the species differentiation of A. actinomycetemcomitans, H. aphrophilus, and H. paraphrophilus.

Clinical and microbiological effects of adjunctive antibiotics in treatment of localized juvenile periodontitis. A controlled clinical trial

The aim of this study was to assess the clinical and microbiologic effects of the combination of amoxicillin and metronidazole therapy as an adjunct to mechanical treatment in the management of localized juvenile periodontitis. Twenty-five localized juvenile periodontitis (LJP) patients from a Brazilian population were randomly allocated into an experimental group receiving mechanical treatment and antibiotics, and a control group receiving mechanical treatment and placebo. Clinical and radiographic assessments, as well as microbiologic sampling for Actinobacillus actinomycetemcomitans, were performed at baseline and one year after the end of the treatment. At the termination of the study A. actinomycetemcomitans could be isolated from the oral cavity of all patients in the control group who harbored the bacterium at baseline and in 4 out of 8 patients in the experimental group. Both treatment modalities resulted in significant benefit on an individual basis. The experimental group, however, displayed better results than did the control group regarding gingival index (GI), probing depth (PD), clinical attachment level (CAL), and radiographic analysis of crestal alveolar bone mass, but not with respect to plaque index (PI). No serious adverse effects of the antibiotic treatment were observed in the present study.

The distribution and transmission of Actinobacillus actinomycetemcomitans in families with localized juvenile periodontitis

The prevalence and distribution of A. actinomycetemcomitans in families where at least one family member (proband) suffered from localized juvenile periodontitis was investigated. 25 probands with localized juvenile periodontitis (LJP) and their 78 close family members were screened for the presence of A. actinomycetemcomitans. Among these 25 families, 10 contained at least one additional family member colonized with oral A. actinomycetemcomitans. Genomic DNA from subgingival A. actinomycetemcomitans strains from each of the probands and their family members were amplified and characterized by the polymerase chain reaction (PCR) using a single primer known to distinguish A. actinomycetemcomitans strains. The PCR products from each strain were separated by electrophoresis on a 1% submarine agarose gel containing ethidium bromide and visualized by UV light transillumination. The studies showed that 41.2% of the parents and 58% of the siblings in this LJP-based population harbored the bacterium. Comparison of the PCR generated amplitypes showed that there was a wide distribution of amplitypes among the probands and immediate relatives. No clear transmission paths were observed in this specific population.

Attachment loss and serum antibody levels against autologous and reference strains of Actinobacillus actinomycetemcomitans in untreated localized juvenile periodontitis patients

Immunological data have been suggested to be a potential tool in the diagnosis, classification and monitoring of periodontal diseases. However, the role of circulating antibodies in periodontal patients is poorly understood. Patients suffering from localized juvenile periodontitis (LJP) are often reported to show high titers of serum IgG antibodies against Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans), but several affected patients do not. Most studies use well-known reference strains of the bacterium for testing against the patients' sera. The aim of the present investigation was to study the relationship between serum IgG antibody levels to autologous A. actinomycetemcomitans strains and clinical attachment loss (CAL). In addition, we wanted to assess the patients' serum titers against 4 well-known reference strains of the bacterium as well as their general potential immunoglobulin response. Intravenous blood samples were taken from 23 LJP patients and 10 healthy individuals, and autologous A. actinomycetemcomitans strains were cultured from 18 of the LJP patients. CAL was measured at 4 different sites around all present teeth and assessed as a % of teeth with at least 1 site moderately > or = 2 < 5 mm) or severely (> or = 5 mm) involved. An enzyme-linked immunosorbent assay (ELISA) was performed to evaluate the serum titers of IgG antibodies to A. actinomycetemcomitans antigens. No significant correlation was found between serum IgG antibody titers to autologous strains and CAL. However, there was a trend that low responders had more moderately affected teeth than had high responders and patients with undetectable A. actinomycetemcomitans levels, which is in agreement with a hypothetically protective role of the antibodies. The total counts of immunoglobulin assessed in all participants showed that the predominant class was IgG and the reference group displayed significantly less (p < 0.05) IgG and IgG1 counts than the LJP patients. Both the reaction pattern against reference and autologous strains varied widely. We conclude that the specific antibody response against A. actinomycetemcomitans shows a weak correlation to clinical attachment levels in LJP patients.

Rapid identification of Actinobacillus actinomycetemcomitans, Haemophilus aphrophilus, and Haemophilus paraphrophilus by restriction enzyme analysis of PCR-amplified 16S rRNA genes

Restriction enzyme analysis of PCR-amplified 16S rRNA genes was used to distinguish among clinical isolates of Actinobacillus actinomycetemcomitans, Haemophilus aphrophilus, and Haemophilus paraphrophilus which were originally identified by conventional phenotypic methods. This PCR-based method is a reliable and rapid alternative to conventional methods for identification of these bacterial species.

Localized juvenile periodontitis and Actinobacillus actinomycetemcomitans in a Brazilian population

Localized juvenile periodontitis (LJP) has been used as a model for studying periodontal disease, and its prevalence is considered to be higher in third-world countries (0.3-8%) than in industrialized countries (0.1%). Mostly, the disease has been associated with Actinobacillus actinomycetemcomitans (A.a.) but lack of association has also been reported. The aim of this study was to identify LJP patients in geographically different Brazilian populations and assess the presence of A.a. in their periodontal lesions. 7843 children, 12-19-years of age, from the cities of Rio de Janeiro, Votorantim and Belo Horizonte were screened, and LJP patients were identified by strict clinical and radiographical criteria. A final LJP prevalence of 0.3%, with a 99% confidence interval between 0.16% to 0.47%, was found. The prevalence in the subpopulations varied between 0.1-1.1% in the different areas. Subgingival bacterial samples were obtained from the oral cavity of 25 patients and their family members. 80% of these patients, 39.5% of their family members, 35.3% of their parents, and 43.9% of all siblings were culture positive for A.a. All but one of the families had at least one member in addition to the patient who was culture positive for A.a. In 3 families, > 1 member showed radiographic and clinical signs of LJP. 30% of non-LJP subjects coming from one of the areas with higher LJP prevalence harbored A.a. We conclude that LJP is highly associated with A.a. in this Brazilian population.

Microbiological and immunohistological findings in a patient with Papillon-Lefèvre syndrome

The following communication is a case history of an 11 year-old female patient suffering from Papillon-Lefèvre syndrome. Since a massive occurrence of A. actinomycetemcomitans had been found in the subgingival microflora of the periodontal pockets, the patient was treated with repeated subgingival scaling, with an adjunct Amoxicillin and Metronidazol treatment. A bacteriological examination of the girl's family proved that several brothers and sisters as well as one parent also carried. A. actinomycetemcomitans, showing 3 different strains of this bacterium within the family. An immunohistological examination of the gingival tissue showed a massive inflammatory infiltrate which was dominated by plasma cells. The histological investigation of the first molars did not show morphological abnormalities of the root cementum. Posttreatment clinical and radiographical improvement of the periodontal conditions is reported despite the recurrent finding of A. actinomycetemcomitans.

PCR primers for the amplification of the 16S rRNA gene of oral bacteria and for the specific identification of Actinobacillus actinomycetemcomitans

The aim of this study was to develop a PCR reaction specific to Actinobacillus actinomycetemcomitans, which targets a widely conserved gene of this bacterium. Two sets of primers were designed based on published sequences of the 16S rRNA of several microorganisms. The first set amplifies a major part of the 16S small subunit rRNA gene of several strains of bacteria commonly found in the periodontal pocket. This reaction produced a 1306 bp-long product and served as a positive control. The second set was specific to A. actinomycetemcomitans and produced a 449 bp-long product. H. aphrophilus and E. coli yielded positive results with the control primers and negative results with the A. actinomycetemcomitans-specific primers. DNA-DNA hybridization was used to validate the identify of the amplified sequences. B. cereus, which is a common contaminator in the laboratory, and human DNA did not generate PCR products in either reaction. The developed primers seen useful for the identification of A. actinomycetemcomitans strains.

Prevalence and distribution of bacteriophage phi Aa DNA in strains of Actinobacillus actinomycetemcomitans

phi Aa is a bacteriophage that was originally isolated by induction of a lysogenic strain of the oral bacterium Actinobacillus actinomycetemcomitans. Since the discovery of phage phi Aa, additional phages infecting several other strains of A. actinomycetemcomitans have been identified. To determine the prevalence of phi Aa or phi Aa-related temperate phages in this species, a phi Aa-specific DNA probe was prepared to screen for homologous sequences among 42 strains of A. actinomycetemcomitans. Fourteen (33%) of the 42 strains examined contained DNA sequences that hybridized with the phage phi Aa probe. A bacteriophage designated phi Aa33384 was isolated by induction from one of the strains (ATCC 33384) that contained a sequence that hybridized with the phi Aa probe. The phi Aa probe hybridized with the DNA extracted from bacteriophage phi Aa33384. The distribution of the phage phi Aa sequence among A. actinomycetemcomitans serotypes was 5/13 (38%) of the serotype a strains, 0/16 (0%) of the serotype b strains, and 9/13 (69%) of the serotype c strains. The results of this investigation suggest that the target sequence prepared from the phage phi Aa genome is fairly common in the A. actinomycetemcomitans chromosome, and that the sequence is distributed among the A. actinomycetemcomitans serotypes in a seemingly nonrandom manner.

Use of a nonradioactive genetic probe identified, synthesized, and labeled in the polymerase chain reaction

This study introduces a strategy to identify and produce sequences useful as genetic markers, or native genetic probes for DNA-DNA hybridization in bacterial strains where the genetics is not well described. Actinobacillus actinomy-cetemcomitans (A.a.) was used as an example. Fifty ng genomic DNA from A.a. ATCC 33384 and Haemophilus aphrophilus ATCC 33389 was amplified in a thermocycler using a single 10-mer primer. The PCR products were separated by electrophoresis on a 1% submarine agarose gel containing ethidium bromide and visualized by UV illumination, and the strain-specific amplitypes were compared. DNA from two bands, 0.9 and 4 kb, unique for the A.a. strain, was cut out, amplified under high stringency with the same primer and labeled by replacing 33.3 microM dTTP with digoxigenin-labeled dUTP in the reaction mixture. The labeled probe was then repeatedly used for hybridization to DNA from various A.a., H. aphrophilus, and other bacterial strains of the Pasteurellaceae family. The results showed that the 0.9-kb probe detected all A.a. tested, and distinguished it from other closely related bacterial species. We conclude that the described strategy is useful for identifying and selecting genetic sequences useful as genetic markers in A.a.

The distribution and transmission of Actinobacillus actinomycetemcomitans in families with established adult periodontitis

The prevalence and genotype distribution of Actinobacillus actinomycetemcomitans strains in families where at least one adult family member (proband) suffered from periodontal disease was investigated to better understand how this periodontal organism is acquired or transmitted. Fifteen probands with severe (established) periodontal disease (EPD) and their 46 immediate family members were sampled for A. actinomycetemcomitans. Among the 15 families, 10 contained at least one additional family member colonized with oral A. actinomycetemcomitans. Genomic DNA from 3 subgingival A. actinomycetemcomitans strains from each of the 10 probands and their 17 family members were amplified and characterized by the polymerase chain reaction (PCR) using a single arbitrary primer known to distinguish A. actinomycetemcomitans strains. The PCR products from each strain were separated by electrophoresis on a 1% submarine agarose gel containing ethidium bromide and visualized by UV light transillumination. The amplification products migrated to form readily distinguishable bands and, since the banding patterns were characteristic of strains of A. actinomycetemcomitans, these patterns were called "amplitypes." The culture studies showed that 51% of all patients suffering from EPD carried oral A. actinomycetemcomitans. Moreover, 50% of their spouses and 30% of their children harbored the bacterium. Comparison of the PCR-generated amplitypes showed that 26 out of 27 individuals had strains exhibiting a single amplitype of A. actinomycetemcomitans, the 27th being colonized by 2 different amplitypes. They also showed that in 6 out of 7 families, the husband and wife did not harbor the same A. actinomycetemcomitans amplitype. Furthermore, most often children carried an an amplitype identical to one of the parents.(ABSTRACT TRUNCATED AT 250 WORDS)

Differentiation of strains of Actinobacillus actinomycetemcomitans by arbitrarily primed polymerase chain reaction

The present study describes a method for amplifying DNA in Actinobacillus actinomycetemcomitans by using short, synthetic oligonucleotides of random sequence as primers in the polymerase chain reaction. Genomic DNA from each of 20 human isolates of A. actinomycetemcomitans was successfully amplified in a thermal cycler with a single synthetic primer (GGGTAACGCC) and reproducibly produced 14 different DNA amplification profiles (amplitypes). A. actinomycetemcomitans isolates from the same subject revealed the same amplitype. The arbitrarily primed polymerase chain reaction appears to be useful in characterizing human isolates of A. actinomycetemcomitans for studies of epidemiology and bacterial transmission.