Suppression of penicillin-resistant oral Actinobacillus actinomycetemcomitans with tetracycline. Considerations in endocarditis prophylaxis

Invasive infections of Aggregatibacter (Actinobacillus) actinomycetemcomitans

BACKGROUND/PURPOSE

Aggregatibacter (Actinobacillus) actinomycetemcomitans, part of the normal flora of the mouth, is frequently found in human periodontal cultures and is an important pathogen causing various invasive infections, particularly infective endocarditis. In this study, we describe the clinical course and outcome of patients with A. actinomycetemcomitans infection.

METHODS

All patients suffering invasive A. actinomycetemcomitans infections at the National Taiwan University Hospital from January 1985 to December 2004 were included in this study. Relevant data regarding clinical presentation, antimicrobial treatment and outcome of these patients were analyzed.

RESULTS

During the study period, there were 11 patients with invasive A. actinomycetemcomitans infections, including eight patients with infective endocarditis, one with osteonecrosis and two with pneumonia and chest wall lesions. Among the patients with infective endocarditis, four had prosthetic valve replacement, four suffered from rheumatic heart disease and one had undergone surgical repair of ventricular septal defect. Lesions in the oral cavity were the probable portals of entry of the microorganism, and included carious teeth, periodontitis or radiotherapy of the ear-nose-throat field, and were noted in nine patients. Transthoracic echocardiography and/or transesophageal echocardiography were performed on the patients with probable infective endocarditis but growth was demonstrated in only four of these patients. Blood culture yielded A. actinomycetemcomitans after prolonged incubation. Three isolates were resistant to penicillin and two of these were also resistant to ampicillin.

CONCLUSION

The diagnosis of invasive A. actinomycetemcomitans infection was delayed due to the indolent clinical course, non-specific presentation and slow growth of the organism. Antibiotic therapy using amoxicillin/clavulanic acid, ampicillin, ampicillin/sulbactam, ceftriaxone, clindamycin, cefotaxime, or levofloxacin was successful in all patients. None of the patients demonstrated recurrence of infection 2-36 months following treatment.

A systematic review on the effect of systemic antimicrobials as an adjunct to scaling and root planing in periodontitis patients

BACKGROUND

Scaling and root planing (SRP) are the bases of non-surgical therapy in the treatment of periodontitis. However, results from this therapy are often unpredictable and dependable from many different factors.

OBJECTIVES

The aim of this systematic review was to evaluate the effectiveness of the adjunctive use of systemic antimicrobials with scaling and root planing (SRP) vs. SRP alone in the treatment of chronic (CP) or aggressive periodontitis (AgP).

SEARCH STRATEGY

Use of computerized databases, namely MEDLINE, the Cochrane Oral Health Group Specialty Trials Register and EMBASE; reference lists from relevant articles were hand-searched; and a hand-search of selected journals until April 2001.

SELECTION CRITERIA

Studies were selected if they were designed as controlled clinical trials in which systemically healthy patients with either AgP or CP were treated with SRP plus systemic antimicrobials in comparison with SRP alone or with placebo, for a minimum of 6 months. Main outcome measures were clinical attachment level (CAL) change and probing pocket depth (PPD) change.

DATA COLLECTION AND ANALYSIS

Two reviewers extracted independently information regarding quality and study characteristics, in duplicate. Kappa scores determined their agreement. Main results were collected and grouped by drug, disease and PPD category. For the quantitative data synthesis, the data was pooled (when mean differences and standard errors were available), and either a Fixed Effects or Random Effects meta-analysis was used for the analysis.

RESULTS

After an initial selection, 158 papers were identified by the manual and electronic searches; 25 papers were eligible for inclusion. Their quality assessment showed that randomization and allocation concealment methods were seldom reported and blindness was usually not defined clearly. In general, selected studies showed high variability and lack of relevant information for an adequate assessment. Overall, SRP plus systemic antimicrobial groups demonstrated better results in CAL and PPD change than SRP alone or with placebo groups. Only limited meta-analyses could be performed, due to the difficulties in pooling the studies and the lack of appropriate data. This analysis showed a statistically significant additional benefit for spiramycin (PPD change) and amoxicillin/metronidazole (CAL change) in deep pockets.

CONCLUSION

Systemic antimicrobials in conjunction with SRP, can offer an additional benefit over SRP alone in the treatment of periodontitis, in terms of CAL and PPD change, and reduced risk of additional CAL loss. However, differences in study methodology and lack of data precluded an adequate and complete pooling of data for a more comprehensive analyses. It was difficult to establish definitive conclusions, although patients with deep pockets, progressive or 'active' disease, or specific microbiological profile, can benefit more from this adjunctive therapy.

Periodontal management of patients with cardiovascular diseases

Periodontists are often called upon to provide periodontal therapy for patients with a variety of cardiovascular diseases. Safe and effective periodontal treatment requires a general understanding of the underlying cardiovascular diseases, their medical management, and necessary modifications to dental/periodontal therapy that may be required. In this informational paper more common cardiovascular disorders will be discussed and dental management considerations briefly described. This paper is intended for the use of periodontists and members of the dental profession.

Resistance profile survey of 50 periodontal strains of Actinobacillus actinomyectomcomitans

BACKGROUND

Antibiotic resistance has been increasingly described among bacterial species colonizing periodontal pockets, particularly in Prevotella and Porphyromonas spp. strains producing beta-lactamases, and frequently associated with resistance to tetracycline and erythromycin. These resistance genes may be carried on motile genetic elements, or transposons, capable of interspecies and intergeneric transmission among bacterial strains colonizing a same ecological niche. The aim of this prospective study was to determine the resistance profile of Actinobacillus actinomycetemcomitans and the prevalence of A. actinomycetemcomitans strains producing beta-lactamases in periodontal pockets.

METHODS

Fifty strains of A. actinomycetemcomitans were isolated from 42 patients with adult periodontitis. No patient had periodontal or antibiotic therapy in the previous 6 months. Bacterial samples were collected from periodontal pockets > or =5 mm, appropriately diluted, inoculated onto selective medium (chocolate blood agar with bacitracin 75 microg/ml and vancomycin 5 microm/ml) and incubated for 5 days at 37 degrees C in air with 5% CO2. After conventional identification, susceptibility testing to 11 antibiotics was performed by the broth dilution method, in trypticase soy broth supplemented with yeast extract, hemin, and 0.1% NaHCO3 to maintain microaerophilic conditions in the microtitration plate wells by CO2 formation.

RESULTS

No strain demonstrated resistance to amoxicillin, amoxicillin-clavulanic acid combination, pristinamycin, or ciprofloxacin at the breakpoint, but 40% of the strains were slightly resistant to penicillin G, and 4% were resistant to erythromycin, 90% to spiramycin, 18% to clarythromycin, 4% to tetracycline, 72% to metronidazole, and 12% to ornidazole. Amoxicillin, followed by tetracycline and erythromycin, was the most effective antibiotic on A. actinomycetemcomitans. The phenotypic research of a beta-lactamase was negative for all the strains tested.

CONCLUSIONS

In this work, most A. actinomycetemcomitans strains were resistant to metronidazole, but the amoxicillin-metronidazole association may be of interest against subgingival anaerobic and capnophilic mixed flora. Pristinamycin and ciprofloxacin appeared as effective alternative monotherapies against A. actinomycetemcomitans. The threat of beta-lactam antibiotic resistance related to beta-lactamase production is currently not a problem with A. actinomycetemcomitans as it has been reported in oral anaerobes.

Local metronidazole application in maintenance patients. Clinical and microbiological evaluation

The purpose of this investigation was to evaluate the clinical and microbiological effect of local antibiotic therapy in comparison with subgingival scaling and root planing in a randomized semi-masked study. Forty-six recall patients who completed systematic periodontal therapy 6 to 24 months prior to the study were enrolled. The inclusion requirements were at least one site with probing depth > or = 5 mm in each quadrant, no scaling, and no antibiotic therapy during the last 6 months. After randomization each patient received 2 different treatments: in 2 quadrants metronidazole 25% dental gel was applied subgingivally to the pockets at day 0 and day 7; scaling and root planing was carried out in the 2 other quadrants, one at day 0 and in the remaining quadrant at day 7. Subgingival microbiological samples were taken from each patient before treatment and on days 21, 91, and 175 after the treatment. The analyses were carried out by indirect immunofluorescence assay. At all treated sites probing depth (PD), clinical attachment level (CAL), and bleeding on probing (BOP) were recorded on days 0, 21, 91, and 175. Both treatments resulted in PD reduction and CAL gain. PD reduction was statistically significant (P < 0.01) for both treatment modalities after 6 months. The CAL gain was not significant for either treatment. There was no statistical significance between scaling and antibiotic therapy. Treponema denticola, Porphyromonas gingivalis, and Prevotella intermedia were significantly reduced after therapy; however, there were no statistically significant differences between treatments. If Actinobacillus actinomycetemcomitans was present before therapy, it was also present after treatment in both groups. The conclusion is that, in recall patients, local application of metronidazole and scaling and root planing showed similar clinical and microbiological effects without statistically significant differences.

In vitro antimicrobial susceptibility of periodontopathic Actinobacillus actinomycetemcomitans to roxithromycin and erythromycin

The in vitro minimal inhibitory concentrations (MIC) and minimal bactericidal concentration (MBC) of roxithromycin and erythromycin against Actinobacillus actinomycetemcomitans were evaluated. Sixty-seven different A. actinomycetemcomitans isolated from periodontal pockets of 101 subjects with different forms of early-onset and adult periodontitis and three reference strains of A. actinomycetemcomitans (ATCC 29522, ATCC 29523, and NCTC 9710) were included in this study. Erythromycin showed poor in vitro activity against A. actinomycetemcomitans; roxithromycin, on the contrary, exhibited good in vitro activity. Moreover, roxithromycin showed the best in vitro antimicrobial activity against 17 serotype a and 12 serotype c subpopulations of A. actinomycetemcomitans; against 38 serotype b subpopulation of A. actinomycetemcomitans, roxithromycin was consistently active. Roxithromycin exhibited MBC values usually equal to, or one-fold higher than MIC values. All the MBC values of erythromycin were three- to four-fold higher than the respective MIC result. Since roxithromycin is characterized by high concentrations in serum and good penetration and diffusion into gingival tissue, it could be expected to pass into the gingival crevicular fluid at levels sufficiently high to inhibit A. actinomycetemcomitans in vivo. These data indicate that roxithromycin might be a potential candidate for therapeutic trials in patients with A. actinomycetemcomitans-associated periodontitis.

Characterization of tetracycline resistance in Actinobacillus actinomycetemcomitans

Comparison of susceptibility data for Actinobacillus actinomycetemcomitans has been difficult because of the lack of standard susceptibility testing conditions. In this study, minimum inhibitory concentration to tetracycline was evaluated by comparing different media, air conditions and incubation times. Ten of 22 (45%) A. actinomycetemcomitans isolated from periodontally diseased sites grew on media supplemented with 4 micrograms per ml of tetracycline, but minimum inhibitory concentrations ranged from 0.125 to 8 micrograms/ml depending on the media and condition used. The best results were obtained with brain heart infusion agar (Difco Laboratories, Detroit MI) incubated in 5% CO2 for 48 h. Eighteen (82%) of the A. actinomycetemcomitans isolates hybridized with the Tet B determinant. The Tet B determinant was transferable between A. actinomycetemcomitans isolates as well as a Haemophilus influenzae recipient and appears to be associated with conjugative plasmids.

Actinobacillus actinomycetemcomitans recovery from extracrevicular locations of the mouth

Associations between recovery of Actinobacillus actinomycetemcomitans from samples of subgingival plaque, and samples of buccal mucosa, tongue and unstimulated saliva were studied in 107 subjects. Ten subjects had gingivitis, 18 localized juvenile periodontitis, 45 rapidly progressive periodontitis and 32 adult periodontitis. Two children suffered from prepubertal periodontitis. Heterogeneity tests for associations in different study populations yielded nonsignificant results. Mantel-Haenszel's common odds ratios were 52.9, 37.2 and 19.8 for respective associations between pooled subgingival samples, and cheek, saliva and tongue samples. Significant McNemar's chi-square of 5.88, 11.25 and 16.96 for respective associations pointed to secondary occurrence of A. actinomycetemcomitans in extracrevicular samples. Multiple linear regression yielded a significant influence of the number of deep periodontal pockets of 7 mm or more and a negative influence of the diagnosis "adult periodontitis" on the log-transformed number of colony-forming units of A. actinomycetemcomitans in samples from cheek mucosa in patients infected with the organism. Extracrevicular occurrence of A. actinomycetemcomitans seems to reflect total subgingival numbers of the organism. Especially sampling cheek mucosa appears to be a promising tool in the diagnosis of a periodontal infection with A. actinomycetemcomitans.

Failure of adjunctive minocycline-HCl to eliminate oral Actinobacillus actinomycetemcomitans

Considerable problems have been reported in the eradication of Actinobacillus actinomycetemcomitans from periodontal sites. The present communication describes the 2-year results of a comprehensive combined mechanical/surgical and adjunctive minocycline (200 mg/day for 3 and another 2 weeks) treatment regimen in 28 patients with A. actinomycetemcomitans-associated periodontitis. Elimination of A. actinomycetemcomitans at periodontal sites was a prerequisite for gain of clinical attachment of > or = 2 mm or decrease of probing depth to < or = 4 mm after subgingival scaling plus minocycline (p < 0.01). Whereas 2 years after active treatment A. actinomycetemcomitans could not be detected at monitored sites in 23 patients, the organism was found on buccal mucosa and in saliva in 17 and 12 cases, respectively. One or 2 years after periodontal surgery, there was a significant association between log10-numbers of A. actinomycetemcomitans in buccal samples and numbers of residual pockets of > or = 7 mm as well as gingival sites with overt gingivitis (R2 = 0.687, p < 0.001). Present results indicate failure of an even prolonged administration of adjunctive minocycline to eliminate oral A. actinomycetemcomitans in most cases of A. actinomycetemcomitans-associated periodontitis.

Antibiotic prescribing practices among Norwegian dentists

There is scarce information on antibiotics prescription habits among dentists in general. The present investigation was undertaken to study some patterns of antibiotics prescription among Norwegian dentists. A total of 459 dentists (approximately 10% of Norwegian dentists) were randomly selected, and to each was mailed a letter describing the survey, accompanied by a questionnaire about age, type of practice, educational background and pattern of prescription of antibiotics. 78% of the dentists responded to these questions. The results indicate that during a typical week, 32% did not prescribe antibiotics, whereas 5% wrote greater than 5 prescriptions. The mean weekly number of prescriptions per dentist was 2.04. Periodontists and oral surgeons prescribed antibiotics significantly more often than did general practitioners and other disciplines. In addition, those with research and/or teaching experience seemed to prescribe significantly more often than those without. More than 1/3 of the sample indicated that they may prescribe antibiotics when treating periodontal diseases. Compared with other disciplines, periodontists prescribed such drugs significantly more often when treating periodontitis, but significantly less often in acute gingivitis, stomatitis and herpes simplex infections. Moreover, 22% of the dentists might prescribe antibiotics when the patient is in pain, 73 and 38% in cases of abscesses with or without generalized malaise, 2.5% in endodontic therapy, 60% to prevent general complications, and 68% for prophylactic use if the patient revealed a history of endocarditis. Norwegian dentists are somewhat restrictive in their prescription of antibiotics, but they mostly prescribe the correct drugs for the different conditions.

E-test: a new technique for antimicrobial susceptibility testing for periodontal microorganisms

The purpose of the study was to validate the Epsilometer test (E-test) method for antimicrobial susceptibility testing of selected periodontopathic microorganisms using the agar dilution method as a standard. The E-test has been developed to provide a direct quantification of antimicrobial susceptibility of microorganisms. The device consists of a predefined, continuous, and exponential gradient of antibiotic concentrations immobilized along a rectangular plastic test strip. After 48 hours incubation a drop-shaped inhibition zone intersects the graded test strip at the inhibitory concentration (IC) of the antibiotic. Twenty-two subgingival plaque samples from periodontitis sites were plated on trypticase soy agar supplemented with 5% rabbit blood or 5% sheep blood and trypticase soy agar supplemented with vancomycin and bacitracin. A total of 60 strains of key periodontal pathogens (Prevotella intermedia, Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Eikenella corrodens, Campylobacter rectus, and Capnocytophaga) isolated from 22 sites of 12 patients were studied. The antibiotics tested were clindamycin, metronidazole, tetracycline, ciprofloxacin, cefoxitin, and ampicillin at concentrations above and below the achieved blood or gingival crevicular fluid levels. As a standard reference the minimal inhibitory concentrations (MICs) were determined using the agar dilution method. MICs were compared with ICs determined using the E-test method. The results showed an agreement ranging from 67% to 100%; sensitivity ranging from 75% to 100%; predictability ranging from 56% to 100% and specificity ranging from 33% to 96%. The E-test ICs for ampicillin, cefoxitin, and metronidazole against the Gram-negative capnophilic and microaerophilic rods and the black-pigmented anaerobic rods ICs for ampicillin, clindamycin, metronidazole, and tetracycline showed a high percentage of agreement with the agar dilution MICS.(ABSTRACT TRUNCATED AT 250 WORDS)

Neutrophil modulation by Actinobacillus actinomycetemcomitans I. Chemotaxis, surface receptor expression and F-actin polymerization

Localized juvenile periodontitis is an early onset periodontitis, usually localized to molars and incisors. Patients usually present with decreased chemotaxis of systemic neutrophils (PMNs) and infection with Actinobacillus actinomycetemcomitans. The pathogenic mechanisms involved have not been clarified. The purpose of this study was to determine if an extract of A. actinomycetemcomitans could induce changes in PMN chemotaxis similar to those reported in LJP patients. It was demonstrated that the bacterial extract was chemotactic for neutrophils. When neutrophils were pre-incubated with the bacterial extract, chemotaxis toward zymosan-activated serum, FMLP and the bacterial extract was inhibited in two different chemotaxis assays (Boyden chamber and under-agarose). Bacterial extract had no effect on random migration in either assay. Pre-incubation with the extract induced increased expression of CD11b/CD18 (Mac-1), Gp110, and FMLP receptors and increased F-actin polymerization following FMLP or PMA stimulation compared to cells not treated with the extract. Treatment of the bacterial extract with proteinase K or phenol extraction reversed the PMN chemotaxis inhibition activity, but increased significantly the random migration of PMNs. Heating the bacterial extract to 56 degrees C had no effect on its activity. The component(s) in the bacterial extract that inhibits chemotaxis is therefore a protein(s), not sensitive to 56 degrees C, and is not endotoxin. This study suggests that A. actinomycetemcomitans may contribute to the pathogenesis of localized juvenile periodontitis by inhibiting chemotaxis. Interference with chemotaxis by A. actinomycetemcomitans, however, occurs through a mechanism other than inhibition of actin assembly, reduction of CD11b/CD18 or Gp110 expression, or blockage/downregulation of FMLP receptors.

Antibiotics in periodontal therapy: advantages and disadvantages

Antibiotic treatment of periodontitis aims at eradicating or controlling specific pathogens. Prime candidates for antibiotic therapy are patients with recently diagnosed active periodontitis or a history of recurrent disease who fail to stabilize following mechanical/surgical therapy. Since a variety of microbes with differing antimicrobial susceptibility profiles may cause periodontitis, selection of antimicrobial agents should be based on proper microbial diagnosis and sensitivity testing, as well as consideration of the patient's medical status. The risk of treating chemotherapeutically solely on the basis of clinical features, radiographic findings or a limited microbiological analysis, is failure to control the pathogens or overgrowth of new pathogens. A review of published papers reveals that appropriate systemic antibiotic therapy may enhance healing in patients with recent or high risk of periodontal breakdown. Systemic antibiotic therapy seems more predictable than topical administration in eradicating periodontal pathogens from deep periodontal pockets. Several promising antimicrobial agents for periodontitis treatment need testing in placebo-controlled, double-blind, randomized clinical trials.

Effect of various graft materials with tetracycline in localized juvenile periodontitis

Ten patients with bilateral, posterior osseous defects associated with localized juvenile periodontitis (LJP) completed the study. Following the initial therapy, osseous defects were surgically debrided and grafted with a 4:1 volume ratio combination of either Synthograft/tetracycline (b-TCP/TTC), Periograf/tetracycline (HA/TTC) or freeze-dried bone allograft/tetracycline (FDBA/TTC). Graft materials were selected randomly for each half mouth following defect debridement, with a different material used on the opposite side for that patient. Immediately following each surgery, patients were placed on doxycycline 100 mg/day for 10 days. Direct re-entry evaluation of 51 osseous defects demonstrated no significant differences among the graft materials regarding hard tissue or soft tissue changes, except for greater percent defect fill for HA/TTC compared to b-TCP/TTC. Significant decreases in defect depth and pocket depth were achieved with each graft material. No adverse reactions to the use of any of the graft materials in combination with local and systemic tetracycline were found. The results indicate all three graft materials used in conjunction with TTC are acceptable and beneficial for the treatment and repair of osseous defects associated with localized juvenile periodontitis.

Tetracycline resistance and TetM in oral anaerobic bacteria and Neisseria perflava-N. sicca

Tetracycline-resistant organisms isolated from six patients with periodontal disease included Bacteroides spp., Eubacterium spp., Fusobacterium nucleatum, Neisseria perflava-N. sicca, Peptostreptococcus anaerobius, Veillonella parvula, and facultative streptococci. All but the Bacteroides spp. and Eubacterium spp. hybridized with the TetM determinant. An additional 417 bacterial strains were screened, and 4% of both the oral streptococci and the Fusobacterium spp. hybridized with the TetM probe.

Chemotherapy in juvenile periodontitis

Juvenile periodontitis has been described as a separate entity among the human periodontal diseases. Several forms of the disease based on the number and types of involved teeth as well as the age of the patient have been reported. The present review deals with the "classical" localized juvenile periodontitis (LJP). The etiology of LJP has been explained according to 3 theories: (1) a genetic (hereditary) defect in the host defense mechanism; (2) a specific infection; (3) a combination of 1 and 2. In all 3 alternatives, bacterial infection is the direct cause of the breakdown of the tissues. This is supported by reports of success following therapy aimed at eliminating the microbial challenge. Arguments favoring the use of chemotherapeutic agents as an adjunct to mechanical debridement, or instead of it, as well as arguments against such use are discussed. The conclusion seems to be dependent on which of the 3 theories of etiology the arguments are related to. If antibiotics are to be used, the choice of drug would depend on the sensitivity of the suspected pathogen(s). At present tetracycline seems to be the one suggested by most authors, but routine use of antibiotics in the treatment of LJP does not seem necessary and is not recommended.

Failure of vancomycin prophylaxis and treatment for Actinobacillus actinomycetemcomitans endocarditis

Reported is a case of Actinobacillus actinomycetemcomitans endocarditis which developed after dental prophylaxis with vancomycin and erythromycin. In vitro results indicated that this isolate and 20 additional isolates were resistant to vancomycin and that potentially useful bactericidal antibiotics for the prophylaxis and treatment of A. actinomycetemcomitans infections included gentamicin, sulfamethoxazole-trimethoprim, cefotaxime, and ciprofloxacin.

Dental bacteremia--a neglected cause of arthroplasty infections? Three hip cases

We report on three patients with late hip replacement infection. The micro-organism was microaerophilic Streptococcus viridans, an oral organism, in all patients. Dental procedures had preceded the onset of the hip infection in all cases, and severe periodontal disease was observed on subsequent admissions.

Microbiological and clinical effects of surgical treatment of localized juvenile periodontitis

Since Actinobacillus actinomycetemcomitans appears to be a key etiologic agent in localized juvenile periodontitis, this study determined the effectiveness of different treatment modalities in suppressing A. actinomycetemcomitans in localized juvenile periodontitis lesions. A total of 25 deep periodontal lesions from 7 patients with localized juvenile periodontitis were included in the study. The test periodontal lesions either received scaling and root planing alone, scaling and root planing together with soft tissue curettage, or modified Widman flap surgery. Subgingival A. actinomycetemcomitans were enumerated using selective culturing. Clinical measurements included changes in probing periodontal attachment level, probing periodontal pocket depth, gingival index, plaque index, and digital subtraction of standardized serial radiographs. The microbiological and clinical effects of treatment were monitored over a period of 16 weeks. All periodontal lesions studied demonstrated high numbers of A. actinomycetemcomitans prior to treatment. Scaling and root planing alone did not markedly change the subgingival A. actinomycetemcomitans counts, nor any of the clinical parameters studied. In contrast, soft tissue curettage as well as modified Widman flap surgery suppressed A. actinomycetemcomitans to undetectable levels immediately after therapy in more than 80% of the lesions studied. A total of 5 periodontal lesions exhibited gain of probing periodontal attachment after subgingival curettage or Widman flap treatment; 3 of these sites revealed no detectable A. actinomycetemcomitans, and the remaining 2 sites harbored only low levels of A. actinomycetemcomitans. 5 periodontal lesions which lost probing attachment after treatment all demonstrated high numbers of subgingival A. actinomycetemcomitans. Changes in alveolar bone, assessed by digital subtraction of serial radiographs, correlated with changes in probing periodontal attachment level, confirming the clinical results. The present study revealed a close relationship between post-treatment A. actinomycetemcomitans levels and the clinical response to treatment, which supports the concept that A. actinomycetemcomitans is an important organism in the etiology of localized juvenile periodontitis. This study also showed that a substantial suppression of subgingival A. actinomycetemcomitans cannot be achieved by periodontal scaling and root planing alone, but can be accomplished by surgical removal of periodontal tissues.(ABSTRACT TRUNCATED AT 400 WORDS)

Actinobacillus actinomycetemcomitans in human periodontal disease

Recent evidence implicates Actinobacillus actinomycetemcomitans in the etiology of localized juvenile periodontitis. This paper reviews the morphological, biochemical and serological charcteristics of A. actinomycetemcomitans, evidence incriminating it as a periodontopathogen, its importance in human nonoral infections, and virulence factors which may be involved in the pathogenesis of A. actinomycetemcomitans infections. A. actinomycetemcomitans is a non-motile, gram-negative, capnophilic, fermentative coccobacillus which closely resembles several Haemophilus species but which does not require X or V growth factors. The organism has been categorized into 10 biotypes based on the variable fermentation of dextrin, maltose, mannitol, and xylose and into 3 serotypes on the basis of heat stable, cell surface antigens. A. actinomycetemcomitans' primary human ecologic niche is the oral cavity. It is found in dental plaque, in periodontal pockets, and buccal mucosa in up to 36% of the normal population. The organism can apparently seed from these sites to cause severe infections throughout the human body such as brain abscesses and endocarditis. There is a large body of evidence which implicates A. actinomycetemcomitans as an important micro-organism in the etiology of localized juvenile periodontitis including: (1) an increased prevalence of the organism in almost all localized juvenile periodontitis patients and their families compared to other patient groups; (2) the observation that localized juvenile periodontitis patients exhibit elevated antibody levels to A. actinomycetemcomitans in serum, saliva and gingival crevicular fluid; (3) the finding that localized juvenile periodontitis can be successfully treated by eliminating A. actinomycetemcomitans from periodontal pockets; (4) histopathologic investigations showing that A. actinomycetemcomitans invades the gingival connective tissue in localized juvenile periodontitis lesions; (5) the demonstration of several pathogenic products from A. actinomycetemcomitans including factors which may: (a) facilitate its adherence to mucosal surfaces such as capsular polysaccharides; (b) inhibit host defense mechanisms including leukotoxin, a polymorphonuclear leukocyte chemotaxis inhibiting factor, and a lymphocyte suppressing factor (c) cause tissue destruction such as lipopolysaccharide endotoxin, a bone resorption-inducing toxin, acid and alkaline phosphatases, collagenase, a fibroblast inhibiting factor and an epitheliotoxin.(ABSTRACT TRUNCATED AT 400 WORDS)

Suppression of the periodontopathic microflora in localized juvenile periodontitis by systemic tetracycline

Since recent studies have implicated Actinobacillus actinomycetemcomitans in the etiology of localized juvenile periodontitis, this investigation determined the effectiveness of subgingival debridement, topical Betadine Solution, and systemic tetracycline in suppressing subgingival A. actinomycetemcomitans and other microorganisms. A total of 20 deep periodontal pockets and 10 normal periodontal sites of 6 localized juvenile periodontitis patients was included in the study. Each patient was treated in 3 stages over a period of 22 weeks, and the result of treatment was monitored for an additional 38 weeks. The first stage of treatment included plaque control, as well as thorough scaling and root planing, composed of at least 6 h of debridement. No concomitant periodontal surgery was performed. In the second stage, Betadine saturated cotton gauze was inserted into the periodontal pockets for 10 min. Stage 3 involved systemic tetracycline therapy (1 g/day) for 14 days. The subgingival microflora was determined at frequent intervals by selective culturing of A. actinomycetemcomitans and Capnocytophaga and by direct microscopic examination. The clinical effect was assessed by measuring changes in probing periodontal attachment level, probing periodontal pocket depth, radiographic alveolar bone mass, and other relevant clinical parameters. Scaling and root planing reduced the total subgingival bacterial counts and the proportions of certain Gram-negative bacteria, but no periodontal pocket became free of A. actinomycetemcomitans. Betadine application had little or no effect on the subgingival microflora. In contrast, tetracycline administered via the systemic route suppressed A. actinomycetemcomitans, Capnocytophaga, and spirochetes to low or undetectable levels in all test periodontal pockets. A. actinomycetemcomitans reappeared in 9 of the deep periodontal pockets after the administration of tetracycline. Most of these 9 pockets became free of detectable A. actinomycetemcomitans during the second week of tetracycline administration, whereas pockets which yielded no A. actinomycetemcomitans after tetracycline therapy became free of the organisms during the first week of tetracycline treatment. This data suggests that systemic tetracycline therapy of localized juvenile periodontitis should, as a practical rule, be continued for 3 weeks. Periodontal destruction continued in 4 deep pockets which all showed high posttetracycline A. actinomycetemcomitans counts. All 6 pockets which demonstrated a marked gain in periodontal attachment yielded no cultivable A. actinomycetemcomitans. No association was found between periodontal disease status and subgingival Capnocytophaga, spirochetes or motile rods. The present study indicates that A. actinomycetemcomitans is an important etiologic agent in localized juvenile periodontitis.(ABSTRACT TRUNCATED AT 400 WORDS)