Characterisation and in vitro and in vivo evaluation of supercritical-CO2-foamed β-TCP/PLCL composites for bone applications

Most synthetic bone grafts are either hard and brittle ceramics or paste-like materials that differ in applicability from the gold standard autologous bone graft, which restricts their widespread use. Therefore, the aim of the study was to develop an elastic, highly porous and biodegradable β-tricalciumphosphate/poly(L-lactide-co-ε-caprolactone) (β-TCP/PLCL) composite for bone applications using supercritical CO2 foaming. Ability to support osteogenic differentiation was tested in human adipose stem cell (hASC) culture for 21 d. Biocompatibility was evaluated for 24 weeks in a rabbit femur-defect model. Foamed composites had a high ceramic content (50 wt%) and porosity (65-67 %). After 50 % compression, in an aqueous environment at 37 °C, tested samples returned to 95 % of their original height. Hydrolytic degradation of β-TCP/PLCL composite, during the 24-week follow-up, was very similar to that of porous PLCL scaffold both in vitro and in vivo. Osteogenic differentiation of hASCs was demonstrated by alkaline phosphatase activity analysis, alizarin red staining, soluble collagen analysis, immunocytochemical staining and qRT-PCR. In vitro, hASCs formed a pronounced mineralised collagen matrix. A rabbit femur defect model confirmed biocompatibility of the composite. According to histological Masson-Goldner's trichrome staining and micro-computed tomography, β-TCP/PLCL composite did not elicit infection, formation of fibrous capsule or cysts. Finally, native bone tissue at 4 weeks was already able to grow on and in the β-TCP/PLCL composite. The elastic and highly porous β-TCP/PLCL composite is a promising bone substitute because it is osteoconductive and easy-to-use and mould intraoperatively.

Lack of Serotype Antigen in A. actinomycetemcomitans

Aggregatibacter actinomycetemcomitans is divided into 6 serotypes. Occurrence of non-serotypeable strains is known, but background reasons are unclear. We hypothesized that non-serotypeable strains represent new serotypes or have altered expression of serotype-specific polysaccharide antigen (S-PA). We first characterized 311 strains from 189 individuals using both immunoassay- and PCR-based serotyping. Next, using natural human infection and rabbit immunization approaches, we clarified whether the phenotypically non-serotypeable strains expressed S-PA. Immunoassay identified serotypes a–f among 216 strains from 159 individuals. The remaining 95 strains from 30 individuals were phenotypically non-serotypeable. Yet, all these strains were identified by PCR-typing as serotype a-, b-, c-, or f. Non-serotypeability was confirmed by Western immunoblot with respective rabbit antisera. Patient sera remained non-reactive with autologous non-serotypeable strains at the serotype-specific region. Rabbit immunization with a phenotypically non-serotypeable strain induced no antibody production against S-PA. Thus, phenotypically non-serotypeable strains did not include novel serotypes, but lacked S-PA expression.

apaH polymorphism in Clinical Actinobacillus actinomycetemcomitans isolates

In the present study the apaH polymorphism in clinical A. actinomycetemcomitans isolates were investigated in relation to their serotype and periodontal status of the donor subjects. The material included 122A. actinomycetemcomitans isolates representing serotypes a-e from 103 periodontally healthy and diseased subjects. The apaH polymorphism was investigated by both restriction analysis of the specific PCR amplification product and also by sequencing of PCR amplification products from selected clinical isolates. An apaH specific PCR amplification product was obtained from all isolates but the restriction patterns of the amplification products varied. Serotype c and genogroup 2 within serotype e formed genetically distinct groups, whereas isolates of serotype a, b, d and genogroup 1 within serotype e could not be separated from each other based on the apaH restriction analysis. No relation between the restriction pattern of apaH and the periodontal status of the individuals was detected. These results indicate that serotype c isolates form a uniformly distinct group within A. actinomycetemcomitans and that a subpopulation of serotype e isolates clearly diverge from all other A. actinomycetemcomitans isolates.

Complement and c4 null alleles in severe chronic adult periodontitis

Severe forms of chronic periodontitis affect up to 10% of adults. Tumour necrosis factor and lymphotoxin-alpha genes in the major histocompatibility complex are associated with severe periodontitis. Complement factor C4 is a nearby, polymorphic, functionally relevant gene region. Although associated with chronic mucosal infections, C4 deficiencies have not been assessed in adult periodontitis patients. We tested whether complement levels are systemically altered and C4 deficiencies associated with severe chronic periodontitis. In a case-control study, we analysed levels of plasma C3, and C4, serum classical pathway haemolytic activity, C4 allotypes and C4 gene numbers in 37 patients with severe chronic periodontitis and in 150 voluntary controls. Plasma levels of C3 were higher, and classical pathway haemolytic activity was lower in patients than in controls. Partial C4 gene deficiencies were more frequent in patients than in controls (odds ratio 2.4, 95% confidence interval 1.1-5.5, P = 0.032). Changes in complement levels may reflect chronic, recurring inflammation. C4 gene deficiencies are associated with predisposition to chronic periodontitis.

Clonal distribution of natural competence in Actinobacillus actinomycetemcomitans

The competence for natural transformation was investigated in 67 Actinobacillus actinomycetemcomitans strains. The transformation assays were performed with both cloned DNA fragments and chromosomal markers of A. actinomycetemcomitans. Competence was found in 12 of 18 serotype a strains, 0 of 21 serotype b strains, 0 of 14 serotype c strains, 3 of 6 serotype d strains, 3 of 4 serotype e strains, 0 of 3 serotype f strains, and 0 of 1 nonserotypeable strain. The transformation frequencies varied from 5 x 10(-3) to 4 x 10(-6) (median 1.5 x 10(-4)). The distribution pattern of natural competence is concordant with the major clonal lineages of A. actinomycetemcomitans. Serotype a strains are predominantly competent for transformation, while serotypes b and c strains are apparently non-competent.

Relationship ofActinobacillus actinomycetemcomitansSerotype b to Aggressive Periodontitis: Frequency in Pure Cultured Isolates

BACKGROUND

To our knowledge, the association of the five serotypes of Actinobacillus actinomycetemcomitans (A. actinomycetemcomitans) to the new diagnostic classification scheme defined by the American Academy of Periodontology in 1999 has not yet been described. The goal of this study was to characterize the frequencies of the five serotypes of A. actinomycetemcomitans in A. actinomycetemcomitans isolates from various forms of periodontitis using both old and new diagnostic classifications and to determine the relationships between serotype and age and clinical diagnosis.

METHODS

A total of 345 A. actinomycetemcomitans isolates from 115 A. actinomycetemcomitans culture-positive subjects (mean age 38.0 +/- 18.3 years, 59% female) were collected. Based on the new classifications, 33 subjects had aggressive periodontitis and 82 chronic periodontitis. According to old classifications, there were six prepubertal periodontitis (PPP), 12 localized juvenile periodontitis (LJP), 15 post-localized juvenile periodontitis (PLJP), 28 refractory periodontitis (Ref-P), and 54 adult periodontitis (AP) cases. Serotypes of A. actinomycetemcomitans were determined by an indirect immunofluorescence assay using serotype-specific polyclonal antisera to A. actinomycetemcomitans strains ATCC 29523, ATCC 43728, ATCC 33384, IDH 781 and IDH 1705 (serotype a, b, c, d, and e, respectively). Proportions of serotype b were examined between different diagnostic and age groups with a Z-test for proportions.

RESULTS

Most subjects (n = 100, 86.96%) were infected with a single serotype (22 serotype a, 44 serotype b, 30 serotype c, 1 serotype d, and 3 serotype e). There were 11 subjects (9.57%) with two serotypes and two subjects (1.74%) with 3 serotypes. Two individuals had isolates lacking any detectable serotype antigen. Serotype b was the predominant serotype in children under 18 years of age and young adults between 19 to 35 years, although serotype b status was not significantly associated with age. Serotypes d and e were not found in patients under 35 years old. In 62 adult patients, one subject had serotype d and three had serotype e. Serotype b was the most common serotype in aggressive periodontitis (60.61%). The proportion of cases with serotype b was significantly higher in aggressive periodontitis compared to chronic periodontitis (P = 0.031). Other serotypes were not significantly associated with new diagnostic categories. Serotypes d and e were not detected in aggressive periodontitis.

CONCLUSION

The results of this study show that proportions of serotype b of A. actinomycetemcomitans are significantly greater in culture-positive patients with aggressive periodontitis than those with chronic periodontitis.

Multiserotype enzyme-linked immunosorbent assay as a diagnostic aid for periodontitis in large-scale studies

Periodontitis is a common chronic oral infection caused by gram-negative bacteria, including Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis. Periodontitis evokes inflammatory host response locally in the periodontium but also systemically. The systemic humoral antibody response against oral pathogens can conveniently be measured by an immunoassay. The aim of the study was to measure serum immunoglobulin G class antibodies against A. actinomycetemcomitans and P. gingivalis by an enzyme-linked immunosorbent assay (ELISA) in which mixtures of several serotypes of the pathogens were used as antigens to avoid biasing of the results in favor of a particular strain. For A. actinomycetemcomitans the antigen consisted of six strains representing serotypes a, b, c, d, and e and one nonserotypeable strain. In the P. gingivalis ELISA, antigens representing serotypes a, b, and c were used. Serum samples from 90 subjects, including 35 samples from patients with diagnosed periodontitis, 10 samples from periodontally healthy controls, and 45 samples from randomly selected apparently healthy volunteers (referred to as "healthy subjects"), were tested. For both pathogens the antibody levels (means +/- standard deviations) of the patients--xpressed as area under the dilution curve--were significantly higher than those for healthy controls or healthy subjects, with values for A. actinomycetemcomitans and P. gingivalis, respectively, as follows: patients, 22.60 +/- 9.94 mm(2) and 26.72 +/- 11.13 mm(2); healthy controls, 9.99 +/- 3.92 mm(2) and 6.90 +/- 3.38 mm(2); and healthy subjects, 16.85 +/- 6.67 mm(2) and 8.51 +/- 4.23 mm(2). The serotype mixture ELISA is suitable for measuring antibodies against periodontal pathogens in large epidemiological studies in order to evaluate the role of periodontitis as a risk factor for other diseases.

Neutrophil free oxygen radical production and blood total antioxidant capacity in patients with coronary heart disease using various medications

Despite convincing results of studies in vitro, less is known about the effects of antioxidants on in vivo redox balance in humans. We developed a novel parameter of in vivo redox balance, and studied it and its relation to dental infections in 51 patients on medication for coronary heart disease (CHD) and 39 random controls matched for age group, sex, social class and locality. In vivo redox balance was the ratio of plasma antioxidant capacity, as measured with radical-trapping assay, to neutrophil respiratory burst capacity, as measured with whole blood chemiluminescence assay. Dental infections were quantitated with four rating scales. CHD patients had higher values than controls. Patients on acetosalicylic acid (ASA), diuretics or beta blockers, but not the ones on calcium channel blocker, had significantly higher redox balance than non-users. Combination of calcium channel blockers and ASA was associated with redox balance similar to taking beta blockers or diuretics. Diuretics and ASA were independent determinants of redox balance in multivariate analyses. Redox balance did not correlate with severity of dental infections (Spearman's r 0.06 to 0.11). The results contrast experimental data indicating that calcium channel blockers are as antioxidants superior to other cardiovascular drugs. Total antioxidant capacity in parallel with oxygen species production capacity should be considered in attempts to solve the antioxidant paradox.

Subgingival strains of Candida albicans in relation to geographical origin and occurrence of periodontal pathogenic bacteria

Clonal diversity of subgingival yeast strains was determined in relation to geographical location and coexistence of selected periodontal pathogenic bacteria. A total of 60 dental patients from Finland, the United States and Turkey each contributed five Candida albicans isolates. C. albicans isolates were serotyped using slide agglutination and genotyped using polymerase chain reaction (PCR) amplification and a random sequence primer. In general, each study subject yielded C. albicans isolates belonging to the same serotype and genotype. C. albicans serotype A occurred more frequently in subjects from Finland and Turkey than in subjects from the United States. A total of 27 PCR-based C. albicans genotypes were identified. One C. albicans genotype occurred with particularly high frequency in subjects from Turkey and another genotype in subjects from the United States. Relationships were identified between C. albicans serotypes and genotypes. Further studies are needed to determine environmental factors of importance for subgingival colonization and persistence of C. albicans.

The Prevotella intermedia group organisms in young children and their mothers as related to maternal periodontal status

Currently, the Prevotella intermedia group includes three biochemically and phylogenetically related species: Prevotella intermedia, Prevotella nigrescens, and the newly described Prevotella pallens. The two first-named species are mentioned with varying emphasis in connection with periodontal diseases, while such a connection of P. pallens is not known. Mothers serve as a plausible source of bacteria to their children, and conceivably, a mother with periodontitis as a recurrent reservoir of periodontally infecting organisms. In the present study, 23 mothers and their young children were examined for the presence of the P. intermedia group organisms in relation to maternal periodontal status (I: periodontal health, II: initial periodontitis, and III: advanced periodontitis). Species differentiation was based on established biochemical methods, electrophoretic mobility patterns, SDS-PAGE, and DNA hybridization. P. intermedia was not recovered from children but nearly exclusively from mothers in group III, thus confirming its association with periodontitis. P. nigrescens and P. pallens were frequently found in mothers and children. To determine bacterial transmission between a mother and her child, 72 isolates from 13 mother-child pairs were analyzed by arbitrarily primed PCR (AP-PCR). Similar AP-PCR types of P. nigrescens and/or P. pallens were recovered from 3/4 pairs in group I, 2/5 pairs in group II, and none in group III. Our results indicate that different species within the P. intermedia group have a different colonization pattern in childhood and that the periodontal status reflects qualitatively their presence in maternal saliva. Intra-familial transmission of P. nigrescens and P. pallens can occur in early childhood, however similar AP-PCR types were most obvious within periodontally healthy mother-child pairs.

Comparison of virulence factors of oral Candida dubliniensis and Candida albicans isolates in healthy people and patients with chronic candidosis

We determined differences in the expression of certain virulence factors between oral Candida dubliniensis and Candida albicans species. In addition, clonal differences were sought among C. albicans isolates recovered from patients with and without compromised immune system. The material comprised 93 clinical yeast isolates originated in 40 subjects (1-5 isolates per subject). All 26 C. dubliniensis isolates and 46 C. albicans isolates originated from healthy routine dental clinic patients. Additionally, 21 C. albicans isolates were collected from patients with autoimmune polyendocrinopathy-candidosis-ectodermal dystrophy (APECED), who have chronic candidosis as one manifestation of their immunocompromising disease. Polymerase chain reaction amplification using the random sequence primer OPE-03 enabled grouping of the C. dubliniensis isolates in 2 genotypes (I and II) and C. albicans isolates in 15 genotypes (I-XV). No significant difference was found in the distribution of genotypes between the patients with APECED and the healthy subjects. C. dubliniensis isolates exhibited high-frequency phenotypic switching significantly more frequently than did C. albicans isolates, and vice versa regarding phospholipase and proteinase production. Proteinase production was significantly more frequent among C. albicans genotype V than genotype IX isolates. No significant difference was found in expression of virulence factors of C. albicans isolates between the patients with APECED and the healthy subjects.

Altered antigenicity is seen in the lipopolysaccharide profile of non-serotypeable Actinobacillus actinomycetemcomitans strains

Non-serotypeable Actinobacillus actinomycetemcomitans strains may be derived from the serotypeable ones. In the present study, we compared the outer membrane proteins (OMPs) and lipopolysaccharides (LPSs) of serotypeable and non-serotypeable A. actinomycetemcomitans strains (n=24) of the same genotype in the same subject (n=6) to find out if alterations on the cell-surface contribute to the non-serotypeability. Serotypeable and non-serotypeable A. actinomycetemcomitans strains showed great similarity in the OMP patterns both within and between subjects. Using serotype-specific antisera, clear immunoblotting LPS profiles in the O-antigenic region were seen in serotype b and c strains but not in non-serotypeable strains from the same subjects. The results suggest that changes in LPS lead to the altered antigenicity of non-serotypeable A. actinomycetemcomitans strains.

Age, dental infections, and coronary heart disease

Epidemiological and intervention studies have suggested that infections are risk factors for coronary heart disease (CHD). Dental infections have appeared as cardiovascular risk factors in cross-sectional and in follow-up studies, and the association has been independent of the "classic" coronary risk factors. This case-control study aimed at detailed assessment of the dental pathology found in various CHD categories (including elderly patients). Altogether, 85 patients with proven coronary heart disease and 53 random controls, matched for sex, age, geographic area, and socio-economic status, were compared with regard to dental status, assessed blindly with four separate scores, and to the "classic" coronary risk factors (seven of the controls had CHD, and they were not included in the analyses). The dental indices were higher among CHD patients than in the controls, but, contrary to previous studies, the differences were not significant (between the CHD patients and their matched controls or among the different CHD categories). This result could not be explained by potential confounding factors. The participants in the present study were older and had more often undergone recent dental treatment in comparison with subjects in our earlier studies. Age correlated with the severity of dental infections only in the random controls but not in the coronary patients who, although young, already had high dental scores. We believe that the higher age of the participants in the present study is the most likely reason for the results. Other possible explanations include an age-related selection bias among older CHD patients, and the fact that those participating in studies like this may have better general health and thus also less severe dental infections. Thus, the role of dental infections as a coronary risk factor varies according to the characteristics of the population studied.

Localization of heat shock proteins in clinical Actinobacillus actinomycetemcomitans strains and their effects on epithelial cell proliferation

Actinobacillus actinomycetemcomitans is an important pathogen in periodontitis. In the present study we localized the GroEL- and DnaK-like heat shock proteins (Hsp) in subcellular fractions of 12 A. actinomycetemcomitans strains of various clinical origin and compared their effects on periodontal epithelial cell proliferation and viability. In all strains, GroEL-like protein was found in the membrane, cytoplasm, and periplasm, whereas DnaK-like protein was present in the cytoplasm and periplasm. No correlation was observed between the Hsp expression and the serotype or origin of A. actinomycetemcomitans strains. The bacterial membrane fractions that expressed the GroEL-like protein moderately or strongly induced epithelial cell proliferation more strongly than strains that expressed the protein weakly. The results suggest that GroEL-like Hsp may play a role in the virulence of A. actinomycetemcomitans by increasing epithelial proliferation.

Heterogeneity of Actinobacillus actinomycetemcomitans strains in various human infections and relationships between serotype, genotype, and antimicrobial susceptibility

Actinobacillus actinomycetemcomitans, an oral pathogen, only occasionally causes nonoral infections. In this study 52 A. actinomycetemcomitans strains from 51 subjects with nonoral infections were serotyped and genotyped by arbitrarily primed PCR (AP-PCR) to determine whether a certain clone(s) is specifically associated with nonoral infections or particular in vitro antimicrobial susceptibility patterns. The promoter structure of leukotoxin genes was additionally investigated to find the deletion characteristic of highly leukotoxic A. actinomycetemcomitans strains. The nonoral A. actinomycetemcomitans strains included all five known serotypes and nonserotypeable strains, the most common serotypes being b (40%) and c (31%). AP-PCR distinguished 10 different genotypes. A. actinomycetemcomitans serotype b strains were more frequently found in blood samples of patients with bacteremia or endocarditis than in patients with focal infections. One AP-PCR genotype was significantly more frequently found among strains originating in focal infections than in blood samples. Resistance to benzylpenicillin was significantly more frequent among A. actinomycetemcomitans serotype b strains than among strains of other serotypes. No differences in the leukotoxin gene promoter region or benzylpenicillin resistance between nonoral and oral A. actinomycetemcomitans strains were observed. Nonoral A. actinomycetemcomitans strains showed great similarity to the oral strains, confirming that the oral cavity is the likely source of nonoral A. actinomycetemcomitans infections. The predominance of serotype b strains in endocarditis and bacteremia supports the hypothesis of a relationship between certain A. actinomycetemcomitans clones and some nonoral infections. The mechanisms behind the exceptionally high rate of occurrence of benzylpenicillin resistance among A. actinomycetemcomitans serotype b strains are to be elucidated in further studies.

Genotyping of Actinobacillus actinomycetemcomitans serotype d isolates based on polymerase chain reaction

The aims of the study were to determine the genetic diversity of the rare Actinobacillus actinomycetemcomitans serotype d and to compare the ability of the repetitive extragenic palindromic element (REP)-based polymerase chain reaction (PCR) with that of the arbitrarily primed (AP)-PCR to discriminate between and within A. actinomycetemcomitans serotypes. The material included 26 A. actinomycetemcomitans serotype d isolates, 3 reference strains, and 21 A. actinomycetemcomitans isolates, representing the previously described 17 AP-PCR genotypes from 4 serotypes (a, b, c and e). Among A. actinomycetemcomitans serotype d isolates (n = 26), the AP-PCR primer distinguished 2 genotypes, whereas the REP-primer pair (REP1R-I and REP2-I) and the (GACA)4 primer each produced one genotype. Among the total of 50 A. actinomycetemcomitans isolates, REP-primer pair distinguished 6 genotypes, the primer (GACA)4 7 genotypes, and the AP-PCR 19 genotypes. Among A. actinomycetemcomitans serotype a isolates (n = 6), REP-primer pair yielded 3 genotypes and (GACA)4 and AP-PCR primer 4 genotypes, and among serotype e isolates (n = 6) 3 genotypes. All serotype b isolates (n = 7), representing the AP-PCR genotypes 2, 9, 8, 12, 13, 16 and serotype c isolates (n = 5), AP-PCR genotypes 3, 4, 14, 15, belonged to the (REP1R-I and REP2-I)-PCR genotype 4 and to the (GACA)4-PCR genotype 4. In conclusion, based on both the AP-PCR method and the less discriminative REP-PCR methods, the present genotyping results indicated limited genetic diversity among serotype d isolates of A. actinomycetemcomitans.

Bacterial adhesion of Actinobacillus actinomycetemcomitans serotypes to titanium implants: SEM evaluation. A preliminary report

BACKGROUND

In this study, the adherence ability of Actinobacillus actinomycetemcomitans serotypes to titanium implant surfaces was evaluated to demonstrate if any selective adherence occurs according to the serotypes of the microorganism.

METHODS

The study material included 3 reference strains of A. actinomycetemcomitans serotypes a, b, and c (ATCC 29523, ATCC 43718, ATCC 33384) and 2 clinical isolates of A. actinomycetemcomitans serotypes d and e (IDH 781, IDH 1705), together with commercially available titanium blade implants. For each strain, bacterial suspensions with identical concentrations (5 x 10(7) cells/ml) were prepared and 0.5 ml of each was added on to the implant surfaces, which had been precoated with glycine-bovine serum albumin (BSA). After incubation at 37 degrees C for 60 minutes in 5% CO2 in air, the implants with attached bacteria were prepared for scanning electron microscopic (SEM) observations. Bacterial adhesion was quantified on the textured body surfaces of the implants, and results were statistically analyzed with analysis of variance followed by Duncan's test. The surface ultrastructure of the bacterial cells was also evaluated descriptively.

RESULTS

The tested strains adhered to implant surfaces in different quantities. Serotype a (ATCC 29523) showed the highest adherence affinity (statistically significant, P <0.01). When compared with each other, serotypes b, c, and d (ATCC 43718, ATCC 33384, and IDH 781) attached equally well, whereas serotype e (IDH 1705) had a statistically significant low adherence capability.

CONCLUSIONS

It is suggested that in vitro A. actinomycetemcomitans adhesion to implant surfaces is strain dependent.

Beta-lactamase production in Prevotella intermedia, Prevotella nigrescens, and Prevotella pallens genotypes and in vitro susceptibilities to selected antimicrobial agents

The present study investigated the beta-lactamase production of 73 Prevotella intermedia, 84 Prevotella nigrescens, and 14 Prevotella pallens isolates and their in vitro susceptibilities to six antimicrobial agents. The P. intermedia and P. nigrescens isolates were recovered from oral and extraoral samples obtained from subjects in two geographic locations from 1985 to 1995. The clonality of the beta-lactamase-positive and beta-lactamase-negative isolates and the clustering of the genotypes were studied by arbitrarily primed-PCR fingerprinting. beta-Lactamase production was detected in 29% of P. intermedia isolates, 29% of P. nigrescens isolates, and 57% of P. pallens isolates. No difference in the frequencies of beta-lactamase production by P. intermedia and P. nigrescens between isolates from oral and extraoral sites, between isolates obtained at different time periods, or between P. intermedia isolates from different geographic locations was observed. However, the P. nigrescens isolates from the United States were significantly more frequently (P = 0.015) beta-lactamase positive than those from Finland. No association between the genotypes and beta-lactamase production or between the genotypes and the sources of the isolates was found. The penicillin G MICs at which 90% of the isolates were inhibited were 8 microg/ml for P. intermedia, 8 microg/ml for P. nigrescens, and 16 microg/ml for P. pallens. For the beta-lactamase-negative isolates, the corresponding values were 0.031, 0.031, and 0.125 microg/ml, and for the beta-lactamase-positive isolates, the corresponding values were 16, 8, and 32 microg/ml. All isolates were susceptible to amoxicillin-clavulanate, cefoxitin, metronidazole, azithromycin, and trovafloxacin. The MICs of amoxicillin-clavulanate and cefoxitin were relatively higher for the beta-lactamase-positive population than for the beta-lactamase-negative population.

Establishment of oral anaerobes during the first year of life

Anaerobic species constitute a significant part of the bacterial community of the mouth. Although the time and species involved in the primary colonization of infants are of great importance by forming the basis for further colonization, the development of the oral anaerobic microflora with age is still inadequately understood. In the present study, time and succession of colonization of oral anaerobes were longitudinally examined in 44 healthy Caucasian infants at 2, 6, and 12 months of age. Unstimulated saliva samples were quantitatively cultured on non-selective Brucella blood agar and several selective media for the isolation of anaerobic micro-organisms. The most frequent anaerobic finding in two-month-old infants was Veillonella spp. The Prevotella melaninogenica group also represented early colonizing species, and the frequency increased remarkably during the first year of life, whereas the Prevotella intermedia group organisms seemed to be late colonizers. Fusobacterium nucleatum, non-pigmented Prevotella spp., and Porphyromonas catoniae were occasional findings in subjects at 2 months but frequent findings in those at one year of age. F. nucleatum was the most frequent strictly anaerobic species in one-year-old infants; other fusobacteria were also occasionally found. The frequency of facultative/micro-aerophilic corroding rods and Capnocytophaga spp. started to increase toward the end of the first year. Except for the common presence of facultative/micro-aerophilic Actinomyces spp., other anaerobic gram-positive species were only occasionally present in these infants. Once established, early-colonizing species tended to persist in the mouth. Our longitudinal study demonstrated the establishment of several anaerobic species with steadily increasing frequencies during the first year of life.

Oral ecology and person-to-person transmission of Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis

The ecological characteristics of the oral cavity are dissimilar for A. actinomycetemcomitans and for P. gingivalis, as judged by differences in their colonization preferences and patterns, associations with periodontal disease parameters, relationships with the subgingival microbiota and the type of periodontitis and their clonal persistence in the oral cavity. These features also suggest that as a periodontal pathogen, A. actinomycetemcomitans is different from P. gingivalis. Probably in most infected individuals, low levels of A. actinomycetemcomitans can persist for years in equilibrium with the host and the resident oral microbiota. However, it is well established that A. actinomycetemcomitans can cause disease in some individuals or in some circumstances when the regulatory mechanisms are unable to maintain homeostasis in the ecosystem. Elevated A. actinomycetemcomitans proportions of the biota can be regarded as a sign of ecological imbalance, leading to increased risk of periodontal destruction. There is also evidence showing elevated pathogenic potential of certain A. actinomycetemcomitans clones. Although A. actinomycetemcomitans seems to be relatively rarely transmitted between cohabiting adults, transmission can occur to periodontally healthy children of A. actinomycetemcomitans-positive parents. Parents and children may share factors that promote successful oral colonization of A. actinomycetemcomitans, or the window of opportunity is in childhood. Therefore, to prevent parent-child transmission of A. actinomycetemcomitans, bacterium-positive parents of young children are optimal targets for enhanced information and treatment. In selected populations, screening for specific clones of A. actinomycetemcomitans has been employed in prevention of peridontitis. Future research aiming at finding the reasons which cause the changes in the oral homeostasis to allow the growth of A. actinomycetemcomitans may give insight into novel prevention strategies for A. actinomycetemcomitans-associated periodontitis. Compared with A. actinomycetemcomitans, P. gingivalis shows a different pattern of coexistence with the host. In periodontal health or in children, P. gingivalis is absent or only rarely detected. When present, P. gingivalis is commonly recovered in high numbers from dentitions exhibiting inflamed periodontitis and poor oral hygiene. Contrary to A. actinomycetemcomitans, the data on the vertical transmission of P. gingivalis are limited. The major infection route of P. gingivalis seems to be between adults, indicating that P. gingivalis commonly colonizes in an established oral microbiota. These characteristics suggest that the degree of tolerance between P. gingivalis and the host is inferior to that between A. actinomycetemcomitans and the host. It appears that the association of P. gingivalis with disease is a rule rather than an accidental incident. On these grounds, it seems that the host-P. gingivalis relationship approaches antibiosis. Since P. gingivalis infection is related to a typical periodontal eco-pathology, the susceptibility to person-to-person transmission of this pathogen may be controlled by periodontal treatment and emphasizing the significance of high standard oral hygiene.

Age-related acquisition of oral and nasopharyngeal yeast species and stability of colonization in young children

The occurrence and stability of colonization of oral yeast species and strains was determined from 40 healthy children during a 22-month follow-up at the ages 2, 6, 12, 18 and 24 months. In addition, salivary samples were obtained from the mothers at baseline (2 months) to study the role of the mother as the source of yeasts for the child. Yeasts were recovered at least once from 17/40 (43%) children by the age of 2 years. Of the 40 children, 11 (28%) were yeast-positive at multiple sampling occasions. No significant differences were found in recovery frequency of yeasts at different ages. Candida parapsilosis was isolated in 18/33 (55%) yeast-positive samples, and it predominated (share of positive findings 76%) at ages 12 to 24 months. The same yeast species was rarely detected in successive follow-up samples and thus on species level yeasts were transient colonizers in the developing oral flora of the children. Of the mothers 20/40 (50%) harbored yeasts. Candida albicans was recovered from 19/20 (95%) of the yeast-positive mothers and C. parapsilosis from none. Only 7/20 (35%) of the mothers with a yeast-positive finding had a yeast-positive child. In 5/7 (71%) of these mother-child pairs, both harbored the same yeast species (C. albicans) and in 3/5 (60%) of the pairs the AP-PCR profiles of the yeast isolates were identical suggesting possible transmission. In children, significant relationships (Fisher's exact-test, P < 0.05) were found between recovery of yeasts and use of pacifier at age over 12 months, eruption of first teeth at age over 6 months, mother cooling the child's food by blowing and mother cleaning the child's pacifier in her own mouth. In mothers, a significant relationship existed between recovery of yeasts and use of antibiotics.

Persistence of oral colonization by the same Actinobacillus actinomycetemcomitans strain(s)

BACKGROUND

The Gram-negative facultatively anaerobic coccobacillus Actinobacillus actinomycetemcomitans is the major pathogen in localized juvenile periodontitis (LJP) and some forms of adult periodontitis (AP). A. actinomycetemcomitans can be grouped into 5 serotypes (a through e) based on differences in the carbohydrate moiety of cell surface lipopolysaccharide. The A. actinomycetemcomitans population is genetically heterogeneous. Since the studies on A. actinomycetemcomitans colonization have mostly applied only culture techniques, the clonality of the follow-up isolates has not been established. Thus, it is possible that, although A. actinomycetemcomitans could be repeatedly isolated from an individual, the initial colonizing strain was replaced by another strain. The aim of the study was to determine whether oral A. actinomycetemcomitans strains change spontaneously over time or after periodontal treatment.

METHODS

A total of 922 A. actinomycetemcomitans isolates were recovered from 115 subjects. From each subject A. actinomycetemcomitans isolates were obtained from 2 to 9 follow-up samples 0.5 to 11.5 years apart. After the first sampling occasion, 99 subjects were treated for either LJP or AP, whereas the 16 non-periodontitis subjects received no treatment. All A. actinomycetemcomitans isolates were serotyped and 235 isolates from 52 subjects genotyped with AP-PCR and/or with ribotyping.

RESULTS

Isolates of only one serotype, or non-serotypeable isolates alone, were repeatedly found in 104 subjects; serotype a occurred in 25%, b in 33%, c in 23%, d in 5%, e in 7%, and non-serotypeable isolates in 8% of these subjects. Two serotypes (or serotypeable isolates together with non-serotypeable isolates) occurred simultaneously in 9 subjects and in each of these subjects at least one of the serotypes was detected at each sampling occasion. In one subject the initial serotype reappeared although a different serotype was once seen alone, whereas in another subject the initial serotype could not be recovered later. Identical genotypes of A. actinomycetemcomitans were repeatedly detected in each of 52 subjects with follow-up isolates of the same serotype.

CONCLUSIONS

The results showed that spontaneous or treatment-induced change in the oral A. actinomycetemcomitans strain(s) is extremely rare and that colonization with the same strain(s) seems to be remarkably persistent.

Actinobacillus actinomycetemcomitans serotype e--biotypes, genetic diversity and distribution in relation to periodontal status

Actinobacillus actinomycetemcomitans isolates from 356 individuals were screened for identification of serotype e in order to investigate its distribution in relation to periodontal status. From subjects with serotype e, 1-6 isolates per subject (n = 61) were genotyped using arbitrarily primed-polymerase chain reaction (AP-PCR) and apaH gene polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) analysis to determine the genetic heterogeneity within the serotype. Furthermore, one serotype e strain per subject was tested for fermentation of 8 carbohydrates for biotyping. Among patients with adult periodontitis (n = 219), localized juvenile periodontitis (n = 55) and other forms of early-onset periodontitis (n = 18) serotypes b, a and c, respectively, were the most frequently detected serotypes. Non-periodontitis subjects (n = 64) were predominantly colonized with serotype c. Serotype e was found in 30 (14%) adult periodontitis patients, 2 (11%) early-onset periodontitis patients and in 5 (8%) non-periodontitis individuals, but in none of the 55 localized juvenile periodontitis patients. AP-PCR distinguished 3 and apaH gene PCR-RFLP analysis 2 genotypes among the 61 A. actinomycetemcomitans serotype e isolates, one genotype per subject. The AP-PCR genotypes 1 and 3 represented the apaH genotype 1 and the AP-PCR genotype 2 the apaH genotype 2. On the basis of variable fermentation of galactose and xylose, 3 biotypes among A. actinomycetemcomitans serotype e were established. Contrary to the absence of A. actinomycetemcomitans serotype e in localized juvenile periodontitis patients, its detection frequency was comparable among other forms of periodontitis and periodontal health. Clinical serotype e isolates form at least 2 genetic types and 3 biotypes.

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.

Characterization of serologically nontypeable Actinobacillus actinomycetemcomitans isolates

Our previous studies have shown that Actinobacillus actinomycetemcomitans isolates of a given arbitrarily primed PCR (AP-PCR) genotype belong to the same serotype (of serotypes a through e). In the present study we investigated whether the AP-PCR genotypes of nonserotypeable A. actinomycetemcomitans isolates match those of the serotypeable isolates. The isolates were additionally characterized by restriction analysis of the apaH PCR amplification products. The material included 75 nonserotypeable and 18 serotypeable A. actinomycetemcomitans isolates from 34 epidemiologically unrelated subjects. The serotypeable isolates were obtained from subjects who also harbored nonserotypeable isolates. Eight AP-PCR genotypes were distinguished among the isolates; six genotypes matched those detected in our previous studies, whereas two genotypes were new. Intraindividually, the A. actinomycetemcomitans isolates produced identical AP-PCR banding patterns, regardless of whether they were serotypeable or nonserotypeable, in 22 of 23 subjects participating with multiple isolates. AP-PCR genotype 3, corresponding to serotype c, was by far the most common among the nonserotypeable isolates (62% of subjects). Results obtained with the apaH restriction analysis confirmed the results obtained with AP-PCR for 31 of the 34 subjects. The results suggest that nonserotypeable A. actinomycetemcomitans isolates originate from serotypeable isolates, especially from serotype c isolates, and the likelihood of the existence of additional serotypes is small.

Role of infection as a risk factor for atherosclerosis, myocardial infarction, and stroke

An increasing body of evidence has linked infections to atherosclerosis and thrombosis. Herpesviruses cause atherosclerosis in experimental animals. Herpesviruses can also be detected in atherosclerotic lesions in humans. Cytomegalovirus may play a role in arteriosclerosis in transplanted hearts, and this virus, together with tumor suppressor protein p53, can be found in restenosis lesions following angioplasty. Chlamydia pneumoniae and dental infections are associated with coronary heart disease in cross-sectional and longitudinal studies, and preceding respiratory infections are associated with ischemic stroke. Infections may favor formation of atherosclerosis and thrombosis by elevation of blood levels of fibrinogen, leukocytes, clotting factor, and cytokines and by alteration of the metabolism and functions of endothelial cells and monocyte macrophages. Low-grade infections may also be one of the causes of the inflammatory reaction observed in atherosclerotic lesions and acute ischemic symptoms, reflected in elevated levels of C-reactive protein. These observations warrant further studies in this field.

Detection of Porphyromonas gingivalis from saliva by PCR by using a simple sample-processing method

Simple sample-processing methods for PCR detection of Porphyromonas gingivalis, a major pathogen causing adult periodontitis, from saliva were studied. The ability to detect P. gingivalis from 118 salivary samples by PCR after boiling and Chelex 100 processing was compared with bacterial culture. P. gingivalis was detected three times more often by PCR than by culture. Chelex 100 processing of saliva proved to be effective in preventing PCR inhibition and was applied to determine the occurrence of P. gingivalis in saliva samples from 263 Finnish subjects between 5 and 80 years of age. The occurrence of P. gingivalis increased with age, and it was detected by PCR in the saliva of 5.0% of subjects between 5 and 10 years of age, 13.8% of subjects between 11 and 20 years of age, 13.4% of subjects between 21 and 30 years of age, and 63.3% of subjects between 31 and 80 years of age. The results indicate that P. gingivalis is a rare finding in saliva from periodontally healthy children and young adults but a frequent one in saliva from adult periodontitis patients.

Biochemical and genetic characterization of a Prevotella intermedia/nigrescens-like organism

Thirty-three previously non-typable faintly pigmented Gram-negative anaerobic bacterial isolates, biochemically most closely related to Prevotella intermedia and Prevotella nigrescens, were analysed for enzymic reactions, cellular fatty acid (CFA) composition, electrophoretic mobility of malate and glutamate dehydrogenases, hybridization with P. intermedia and P. nigrescens species-specific oligonucleotide probes and, for genetic heterogeneity, by arbitrarily primed PCR (AP-PCR). P. intermedia ATCC 25611T and P. nigrescens ATCC 33563T were run in parallel for comparison. Twenty-nine isolates originated from the normal oral flora of 18 subjects (including five mother-child pairs), and four isolates from various infections. Except for a negative lipase reaction, enzymic profiles of the test isolates were similar to those of P. intermedia and P. nigrescens. Clustering of CFAs, electrophoretic mobility patterns, hybridization with DNA probes for P. intermedia and P. nigrescens, and AP-PCR band patterns of the test isolates differed from those of the type strains of P. intermedia and P. nigrescens, suggesting the existence, in humans, of a new anaerobic species of pigmented, moderately saccharolytic, indole-positive Gram-negative rods.

Periodontitis patient and the spouse: periodontal bacteria before and after treatment

Suspected periodontal pathogens can be transmitted between spouses. The treatment response may be unsuccessful in periodontitis patients, if the spouse harbors these bacteria. The aim of the present 6-month follow-up study was to clarify whether the microbiological treatment outcome of periodontitis patients is related to the detection of suspected periodontal pathogens in the saliva of the spouse. 10 patients with advanced periodontitis and their spouses were included in the study. The patients received mechanical periodontal treatment and 500 mg metronidazole systemically 2x a day for 7 days. The presence of visible plaque, gingival bleeding after probing, suppuration, supragingival and subgingival calculus and pocket depths were assessed at baseline and 1 and 6 months after treatment. Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia/Prevotella nigrescens, Campylobacter rectus and Peptostreptococcus micros were cultured from pooled subgingival samples from the patients and from salivary samples from the spouses at corresponding occasions. Periodontal conditions in the patients improved after treatment as determined by the significantly lower values of clinical variables 1 and 6 months after treatment compared to those at baseline. However, the re-emergence of periodontal bacteria after treatment of the patients was not related to the concurrent detection of the respective bacteria in the saliva of the spouses. In this study design, it seemed that the salivary bacterial load in the spouse was of minor importance for the microbiological treatment outcome of the patient.

Phenotypic and genotypic characterization of oral yeasts from Finland and the United States

A total of 4-22 isolates of oral yeasts per subjects from 48 yeast-positive Finnish and American subjects (25 females and 23 males) were phenotyped and genotyped to determine the frequency of simultaneous oral carriage of multiple yeast taxa. An oral sample from either periodontal pockets, oral mucosa or saliva was obtained. All subjects yielded Candida albicans and 3 subjects an additional yeast species (Candida krusei, Candida glabrata or Saccharomyces cerevisiae). The API 20C Aux kit distinguished 9 different carbohydrate assimilation profiles among the C. albicans isolates. Thirty-eight of 46 C. albicans biotype I isolates were categorized in a single numerical profile. PCR analysis, using a random primer OPA-03 and a repetitive primer (GACA)4, detected 2 major genotypic groups among the C. albicans isolates; 44 subjects showing isolates with a "typical" PCR-profile and 4 subjects isolates with an "atypical" PCR-profile. The "atypical" PCR-profile was similar to that of Candida dubliniensis. All C. albicans isolates assimilated xylose, except 5, including the 4 with an "atypical" PCR-profile. No difference was found in distribution of oral yeast species, and of C. albicans phenotypes and genotypes between Finnish and American subjects. The present PCR method may offer a rapid and easy means of distinguishing oral Candida species.

Can one acquire periodontal bacteria and periodontitis from a family member?

Recent findings suggest that two major periodontal pathogenes, Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis, are transmitted among family members. The authors discuss the evidence of person-to-person transmission of periodontal bacteria, the significance of saliva as a vehicle of transmission and the methods of verifying clonal similarity of bacterial strains obtained from family members. The authors also discuss the prophylactic and therapeutic implications of the person-to-person spread of periodontal bacteria.

beta-lactamase production by oral pigmented Prevotella species isolated from young children

The frequency of beta-lactamase production by oral pigmented Prevotella species isolated from 23 healthy young children and the minimal inhibitory concentrations (MICs) for 186 available beta-lactamase-positive isolates were examined by using the chromogenic cephalosporin disk test (AB BIODISK, Solna, Sweden) and the Etest (AB BIODISK) and/or the agar dilution method of the National Committee for Clinical Laboratory Standards (Villanova, PA, USA), respectively. beta-Lactamase-positive Prevotella melaninogenica strains were isolated from all children, and more than two-thirds of the Prevotella denticola and Prevotella loescheii strains isolated from the children were beta-lactamase-positive. The beta-lactamase-producing Prevotella intermedia group consisted of Prevotella nigrescens and the P. intermedia/ P. nigrescens-like organism (PINLO); P. intermedia was not found. Only two P. nigrescens isolates but most of the PINLO isolates produced beta-lactamase. The MICs for beta-lactamase-producing strains varied between 0.38 and 64 micrograms/mL. beta-Lactamase production by oral pigmented Prevotella species colonizing young children is already frequent. The phenomenon should be taken into account in the treatment of pediatric anaerobic infections of oral origin.

Role of Porphyromonas gingivalis, Prevotella intermedia, and Prevotella nigrescens in extraoral and some odontogenic infections

Porphyromonas gingivalis, Prevotella intermedia, and Prevotella nigrescens were isolated from 138 subjects with various infections (intraabdominal, skin and soft-tissue, head and neck, pleuropulmonary, and odontogenic infections and bacteremia). The phenotypic identification of 173 isolates was completed by molecular methods. Arbitrarily primed polymerase chain reaction (AP PCR) analysis was used to determine the genetic similarity of intraindividual P. intermedia/P. nigrescens group isolates recovered from 12 subjects. All 19 P. gingivalis isolates (16 intraabdominal isolates and three odontogenic isolates) hybridized with the P. gingivalis-specific DNA probe. Of the 154 P. intermedia/ P. nigrescens group isolates, 74 were identified as P. intermedia; 78, as P. nigrescens; and 2, as P intermedia/P. nigrescens-like isolates. P. intermedia and P. nigrescens were isolated with equal frequency from patients with all other infections except those with bacteremia, from whom only P. nigrescens isolates were recovered. There were 12 cases in which multiple P. intermedia/ P. nigrescens group isolates were recovered; in nine, only one of the species was isolated, whereas in three, two different species were detected. The intraindividual isolates representing the same species always exhibited identical AP PCR genotypes.

Production of glucosyltransferases by clinical mutans streptococcal isolates as determined by semiquantitative cross-dot assay

Forty-four clinical isolates of mutans streptococci were examined by a semiquantitative cross-dot assay for in vitro production of glucosyltransferases GTF-I, GTF-SI and GTF-S of Streptococcus mutans, and GTF-I of Strep. sobrinus, using monospecific antibodies. The isolates were obtained from 12 1.5- to 3-year old children, six caries-active and six caries-free, and from their mothers. The isolates were selected originally from 243 isolates and they represented 35 genetically distinct types as analysed by serotyping and ribotyping. 27 isolates were of serotype c, nine of serotype e and eight of serotype g. Mother child pairs shared nine ribotypes, suggesting vertical transmission. The results showed that, when cultured in Todd-Hewitt broth supplemented with 1% glucose, all Strep. mutans isolates produced GTF-I and GTF-S and all except two produced GTF-SI of Strep. mutans. All Strep. sobrinus isolates produced GTF-I of Strep. sobrinus. The Strep. mutans GTF-I, GTF-SI and GTF-S production of isolates exhibiting a different ribotype showed variability. The variability of GTF-SI and GTF-S production was less pronounced for serotype e isolates. The GTF-I production by Strep. sobrinus isolates did not vary. Transmitted strains produced the same levels of GTFs as strains that were distinct (not transmitted). Strep. mutans isolates of caries-active children produced the same levels of GTF-I and GTF-S, but tended to produce lower levels of GTF-SI than isolates of caries-free children. In conclusion, the results suggested that Strep. mutans isolates exhibiting a different ribotype often had differences in production of GTFs. However, no clear superiority of the high-producer over the low-producer strains was found in regard to their colonization or caries promotion in young children.

Periodontal findings in Cohen syndrome with chronic neutropenia

Radiographic periodontal status and microbiological findings of periodontal pockets in subjects with Cohen syndrome are presented in this report. This hereditary disorder causes mental retardation, and neutropenia is one feature of the syndrome. Fifteen patients with Cohen syndrome and 15 controls matched for age and sex and, as far as possible, according to the degree of mental retardation were examined. Alveolar bone loss was evaluated from the panoramic radiographs. Two subgingival samples were obtained from the most affected anterior and posterior periodontal sites in each dentate subject and examined for the occurrence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia/nigrescens, Peptostreptococcus micros, Bacteroides forsythus, and Campylobacter rectus. Subjects with Cohen syndrome had alveolar bone loss more frequently and the bone loss was more extensive (Mann-Whitney U-test: P < 0.05) than in the controls. They also harbored one or several of the putative periodontal pathogens (Mann-Whitney U-test: P < 0.001) more often than the controls. We conclude that subjects with Cohen syndrome have increased susceptibility to early periodontal breakdown which is likely to be associated with neutropenia.

Occurrence of temperate bacteriophages in different Actinobacillus actinomycetemcomitans serotypes isolated from periodontally healthy individuals

The occurrence of temperate bacteriophages was studied in 34 isolates of Actinobacillus actinomycetemcomitans derived from 27 periodontally healthy Finnish individuals both by lysis/plaque assays and by DNA hybridizations. In addition the serotype, the ribotype and the arbitrarily primed polymerase chain reaction (AP-PCR) profile were determined for each A. actinomycetemcomitans strain. Fourteen isolates showed hybridization patterns very similar to that of a known lysogen when probed with the genome of the previously characterized temperate phage Aa phi 23. Only 6 of these 14 strains had produced lysis or single plaques on suitable indicator strains. Phage Aa phi 247 derived from one of these lysogens was indistinguishable from Aa phi 23 by electron microscopy, and the genomes showed highly related DNA hybridization patterns. The remaining 20 isolates exhibited hybridization patterns very different from that of Aa phi 23 DNA. Seven of these strains also gave lysis or single plaques, suggesting that 21 of the 34 strains were lysogenic. These data indicate that the prophages per se do not represent a virulence factor exclusively associated with periodontal disease. Presence of an Aa phi 23-related prophage correlated with serotype a and AP-PCR type 1 of the bacterial host. This may indicate that Aa phi 23 and related phages have a limited host range.

Likelihood of transmitting Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis in families with periodontitis

This study examined the frequency of spouse-to-spouse and parent-child transmission of the periodontal pathogens Actinobacillus actinomycetemcomitans (124 subjects in 47 families) and Porphyromonas gingivalis (78 subjects in 31 families). The two test organisms were recovered from subgingival and tongue surface specimens using established microbiological techniques. Arbitrarily primed polymerase chain reaction (AP-PCR) was used to genetically characterize isolates of the test species. The probability of isolating identical AP-PCR types of A. actinomycetemcomitans and P. gingivalis in family members by chance was estimated from the AP-PCR genotype distribution of the two species among unrelated individuals. A probability of 5% or less for occurrence by chance alone suggests intra-familial transmission. With a bacterium-positive spouse, A. actinomycetemcomitans revealed inter-spousal transmission in 4/11 (36%) married couples and P. gingivalis in 2/10 (20%) married couples. Parent-child transmission of A. actinomycetemcomitans took place in 6/19 (32%) families. P. gingivalis was not transmitted from parent to child in any of the study families. The intra-familial transmission of A. actinomycetemcomitans and P. gingivalis may in part explain a familial pattern of periodontitis and may have important prophylactic and treatment implications.

Similarity of salivary and subgingival Prevotella intermedia and Prevotella nigrescens isolates by arbitrarily primed polymerase chain reaction

The distribution and the genetic similarity of Prevotella intermedia and Prevotella nigrescens in saliva and in subgingival samples recovered from the same subject were studied in 16 subjects with different periodontal status. The isolates (4 salivary and 4 subgingival P. intermedia/nigrescens group isolates per subject) were identified to species level by hybridization with species-specific oligonucleotide probes, and the clonal analysis was performed using arbitrarily primed polymerase chain reaction (AP-PCR) (all isolates) and ribotyping (isolates from 5 subjects). In addition, the applicability of AP-PCR in differentiating between P. intermedia and P. nigrescens species was tested using 18 P. intermedia and 20 P. nigrescens isolates from 34 subjects. P. intermedia was detected in 7 and P. nigrescens in 14 of the 16 subjects. In all subjects the same species was found both in saliva and in subgingival plaque. In 15 of the 16 subjects, similar AP-PCR types of P. intermedia and/or P. nigrescens between salivary and subgingival samples were found. The salivary and subgingival isolates that were similar by AP-PCR were indistinguishable also by ribotyping. The AP-PCR analysis revealed a P. intermedia or P. nigrescens species-specific AP-PCR product in most isolates. This study indicates that both P. intermedia and P. nigrescens were found both in salivary and in subgingival samples, and both sampling sites within the same individual were usually colonized with identical AP-PCR types of the species. Thus, in addition to a subgingival sample a salivary sample seems to be suitable for detection and clonal analysis of these species. The AP-PCR method proved to be a simple method applicable for differentiation and clonal analysis of P. intermedia and P. nigrescens.

Typing of mutans streptococci by arbitrarily primed polymerase chain reaction

The discriminative power of the arbitrarily primed polymerase chain reaction (AP-PCR) in differentiating between Streptococcus mutans and Strep. sobrinus species, serotypes and clones was investigated. Mutans streptococcal isolates (12(7)) obtained from 65 individuals (1-10 isolates per individual) were AP-PCR typed separately with two random primers, OPA-05 and OPA-13. Bacterial cell lysates were used as a template in PCR reactions, which made AP-PCR easy and fast to perform. Eighty-one isolates from 19 individuals were also ribotyped to compare the discriminative ability of ribotyping and AP-PCR techniques. AP-PCR performed with the two primers differentiated between Strep. mutans and Strep. sobrinus isolates, but neither primer detected serotype-specific amplification products. OPA-05 distinguished two main AP-PCR patterns among Strep. mutans isolates and one main pattern among Strep. sobrinus isolates, whereas OPA-13 found one main AP-PCR pattern among Strep. mutans isolates and two main patterns among Strep. sobrinus isolates. Ribotyping and AP-PCR revealed 40 and 33 different types among 81 selected isolates, respectively. Both techniques detected intra-individual heterogeneity in 16 out of 19 participants. The results indicate that AP-PCR has good discriminative ability in differentiating between mutans streptococcal clones and that the technique is suitable for epidemiological studies on mutans streptococci.

Acute tongue abscess: report of two cases

Tongue abscesses are extremely rare. Two cases caused by periodontal pathogens are presented.

Concentrations of tinidazole in gingival crevicular fluid and plasma in dogs after multiple dose administration

Tinidazole 15 mg/kg was administered to eight Beagle dogs with gingivitis or periodontitis twice daily for 3 days. Tinidazole concentrations in blood and gingival crevicular fluid (GCF) were measured 1, 3, 6 and 9 h after the morning dose each day. The concentration of tinidazole was determined by high performance liquid chromatography (HPLC). The mean concentration of tinidazole in GCF for each dog ranged from 6.05 to 9.32 micrograms/mL at different time points after the first dose, and on the first day the highest concentration was observed 6 h after the drug administration. Tinidazole concentrations were 34 +/- 4%-72 +/- 9% (mean +/- SEM) of simultaneous plasma concentration. At steady-state, on the third treatment day, the mean tinidazole concentrations in GCF ranged from 6.68 to 13.1 micrograms/mL, i.e. 44 +/- 6%-75 +/- 25% of the corresponding concentrations in plasma. Tinidazole concentration in GCF exceeded the MIC values for putative path-ogenic periodontal bacteria and it is concluded that, when indicated, tinidazole could be used for chemotherapy of periodontitis in dogs.

Source of suspected periodontal pathogens re-emerging after periodontal treatment

To clarify the source of re-emerging periodontal pathogens after treatment, we compared the ribotypes of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia/Prevotella nigrescens group and Campylobacter rectus before and after treatment in 7 periodontitis patients and in 6 of the spouses. The patients harbored A. actinomycetemcomitans, P. gingivalis, P. intermedia/P. nigrescens group or C. rectus in their subgingival or salivary samples before treatment. The respective bacterial species were not detected 1 month after treatment, but reappeared by 6 months later. When available, 4 random colonies of each of the 4 species were isolated from both subgingival and salivary samples at each sampling occasion, the isolates were subcultured, identified and typed applying pheno- and genotypic intraspecies characterization methods. Altogether 90 strains of A. actinomycetemcomitans, P. gingivalis, P. intermedia/P. nigrescens group and C. rectus were available from 2, 3, 2 and 4 patients, respectively. The pre- and post-treatment ribotypes of A. actinomycetemcomitans-, P. gingivalis- and P. intermedia/P. nigrescens group-isolates were identical in all respective patients. The pre- and post-treatment ribotypes of C. rectus were identical in 1 of 4 patients, whereas 2 patients harbored a previously not detected post-treatment ribotype and 1 patient harbored the initial and a previously not detected post-treatment ribotype. To study the possibility that periodontitis patients may acquire strains from the spouse after treatment, isolates of A. actinomycetemcomitans, P. gingivalis, P. intermedia/P. nigrescens group and C. rectus (n = 95) from the patients' spouses were ribotyped and compared with those of the patients. The patient exhibited his own post-treatment ribotypes, different from those of the spouse, of A. actinomycetemcomitans and P. gingivalis in 1 couple and of P. intermedia/P. nigrescens group and C. rectus in 1 couple. In the 2 patients who harbored a previously not detected post-treatment ribotype of C. rectus, one patient shared the new ribotype with the spouse, whereas the other one did not. Although an exogenous source cannot be fully ruled out, the patient's own oral flora seems to be the main source of re-emerging periodontal pathogens after treatment.

Value of some laboratory and clinical measurements in the treatment plan for advanced periodontitis

In our previous study, we reported that only 13 of 46 adult patients with advanced periodontitis responded well to initial non-surgical periodontal therapy. In the present follow-up study, the remaining 33 patients were randomly treated further using either modified Widman flap surgery or systemic metronidazole. The patients responding unsatisfactorily to this 2nd treatment phase, received supplementary systemic chemotherapy or surgery, respectively. By using this study design, we determined which baseline clinical variables and/or laboratory findings predicted the treatment outcome in these study patients. Clinical variables included the assessment of bleeding, suppuration, probing pocket depth, furcation lesions, relative attachment level and radiographic infrabony defects. Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis were cultured from subgingival plaque samples. The specific IgG and IgA antibody levels against 5 serotypes of A. actinomycetemcomitans were determined in serum and saliva. Elastase-like, trypsin-like and general protease activities were assessed from saliva. The bivariate statistical analyses showed that the most pronounced difference between the patients responding well to initial non-surgical therapy (group MC, n = 13), to either supplementary surgery or chemotherapy (group FT1, n = 11), or those responding to the complex therapy (group FT2, n = 17), was the prior extent of periodontal destruction expressed as the proportion of > or = 6 mm deep periodontal pockets. When multiple linear regression was used to investigate the influence of clinical and laboratory findings on the variation of treatment response between the 3 groups, the most significant explanatory factor was the simultaneous presence of subgingival A. actinomycetemcomitans and multiple deep periodontal pockets. None of the immunological or biochemical variables used had any further influence in the model. Pretreatment microbiological examination, especially for the detection of A. actinomycetemcomitans, seems to be a valuable laboratory screening method for identifying complex treatment need in adult patients with advanced periodontitis. However, the evaluation of the extent and pattern of periodontal breakdown remains crucial for choosing the treatment strategy including surgery and/or chemotherapy in A. actinomycetemcomitans-infected adult periodontitis patients.

Distribution and genetic analysis of oral Prevotella intermedia and Prevotella nigrescens

A total of 344 Prevotella intermedia and nigrescens group isolates from 59 subjects were identified by hybridization with nonradioactively labeled species-specific oligonucleotide probes. Identification of 20 P. intermedia and 46 P. nigrescens isolates was confirmed by analyzing the electrophoretic mobilities of malate and glutamate dehydrogenase enzymes. A total of 111 isolates (32%) were identified as P. intermedia and 233 isolates (68%) as P. nigrescens. Identification performed with oligonucleotide probes and with malate and glutamate dehydrogenase electrophoresis matched perfectly. The distribution of oral P. intermedia and P. nigrescens in various periodontal status groups was investigated in periodontally healthy or diseased individuals. To reveal intra- and interindividual genetic diversity and possible intrafamilial transmission, P. intermedia and P. nigrescens isolates from 16 to 59 subjects, representing 8 married couples, were ribotyped. The stability of colonization was examined in 12 of the 59 subjects, of whom 6 received periodontal treatment and 6 were untreated. All children and periodontally healthy adults and most subjects with initial periodontitis (13/21) harbored only P. nigrescens. Of the 20 subjects with advanced periodontitis, 7 harbored both P. intermedia and P. nigrescens, 7 only P. intermedia and 6 only P. nigrescens. One or two ribotypes of P. intermedia and/or P. nigrescens were found intraindividually. The spouses in 5 of the 8 married couples shared an identical ribotype of P. intermedia or P. nigrescens, whereas ribotypes from unrelated subjects were mostly unique. Colonization was stable, since the same ribotypes were found 1-6 months apart in both periodontally treated and untreated subjects. In conclusion, the study indicates that P. intermedia and P. nigrescens may occur simultaneously in the oral cavity, the colonization is stable and P. intermedia is associated with periodontal diseases. Ribotyping revealed considerable genetic heterogeneity in unrelated subjects, whereas isolates obtained from spouses could represent the same ribotype, which suggests transmission of these species.

Oral colonization by more than one clonal type of mutans streptococcus in children with nursing-bottle dental caries

By ribotyping the genetic diversity of mutans streptococci in six 1.5-3-yr-old children with nursing-bottle caries and in six caries-free, age-matched children and in their mothers was examined. The proportion of mutans streptococci in the dental plaque of the children and their levels in the saliva of the mothers were also examined. For ribotyping, chromosomal DNA of isolates obtained from the plaque of the children (3-12 isolates per child) and from the saliva of the mothers (4-13 isolates per mother) was digested with restriction endonuclease HindIII. The DNA fragments were hybridized to the plasmid pKK3535 which contains the rRNA operon of the Escherichia coli chromosome. The results showed that children with nursing-bottle caries exposed to frequent consumption of sucrose had a high proportion of mutans streptococci in plaque and four of them were colonized with more than one ribotype, whereas caries-free children had a low proportion of mutans streptococci in plaque and only one of them harboured more than one ribotype. Mothers of children with nursing bottle caries had similar levels and numbers of ribotypes of mutans streptococci in saliva as the mothers of the caries-free children. In both child groups, mothers were probably the main source of infection with mutans streptococci. Thus, children with nursing-bottle caries were not only heavily infected with mutans streptococci but also often colonized with more than one clonal type. In the child's acquisition of such clones, frequent sugar consumption may have an important role.