Bacterial antibody titers in ligature-induced periodontitis in beagle dogs

Evaluation of Subgingival Bacteria in the Dog and Susceptibility to Commonly Used Antibiotics

The aim of the present investigation was to evaluate the subgingival aerobic and anaerobic flora of 13 dogs with periodontal disease and the susceptibility of these bacteria to antibiotics currently approved in Italy for treatment of canine infections. Of the anaerobic bacteria, Bacteroides fragilis was most frequently isolated, followed by Peptostreptococcus + Porphyromonas gingivalis and Prevotella intermedia. Of the aerobic bacteria, α-hemolytic Streptococcus was most frequently isolated, often associated with Escherichia coli or Pasteurella multocida. Resistance of anaerobic and aerobic bacteria to various antibiotics was generally high. Anaerobic bacteria appeared to be susceptible to amoxicillin + clavulanic acid, doxycycline, and erythromycin; aerobic bacteria appeared to be susceptible to amoxicillin + clavulanic acid, erythromycin, gentamycin, and sulfa-trimethoprim. Bacteroides fragilis was resistant to all of the antibiotics tested. The emerging worldwide problem of bacterial resistance to antibiotics resulting from overuse and misuse of antibiotics is discussed.

A Model of Spontaneous Periodontitis in the Miniature Goat

BACKGROUND

The pathogenesis and progression of periodontal disease have been extensively studied through the use of animal models. However, no animal model has yet been established that is precisely similar to periodontitis in humans. In the present study, we examined the use of Shiba goats as a model for spontaneous periodontitis.

METHODS

Thirty-four Shiba goats (seven males and 27 females, aged 10 to 98 months) were used. We examined periodontitis in Shiba goats clinically, histopathologically, and microbiologically.

RESULTS

The mean probing depth (PD) of the 68 teeth examined was 2.7 +/- 0.8 mm. The incidences of PD > or =3 and 4 mm were 46.4% and 22.1%, respectively. The incidence of bleeding on probing in 68 sites and in 34 animals was 60.7% and 73.5%, respectively. The formation of vertical alveolar bone defects and downgrowth of gingival epithelial cells were found in the areas of periodontitis. The prevalence of Tannerella forsythensis, Campylobacter rectus, Fusobacterium necrophorum, Fusobacterium nucleatum, and Actinobacillus actinomycetemcomitans in subgingival plaque by polymerase chain reaction was 46.4%, 28.5%, 28.5%, 17.8%, and 3.5%, respectively. These percentages were increased in subgingival plaque from PD > or =3 mm.

CONCLUSIONS

The clinical, histopathological, and microbiological features of spontaneous periodontitis in Shiba goats were somewhat similar to those in human periodontitis. Moreover, there are some advantages of using the Shiba goat; the size of the oral cavity is suitable for periodontal treatment, and handling and housing are relatively easy. Therefore, these results suggest that the Shiba goat is a useful animal model for human periodontitis.

Ovine periodontitis as a potential model for periodontal studies. Cross-sectional analysis of clinical, microbiological, and serum immunological parameters

OBJECTIVES

: To investigate infection and host immunity patterns in sheep with naturally occurring "broken-mouth" periodontitis.

MATERIALS AND METHODS

: Eight periodontally healthy (HS) and eight periodontally diseased ewes (PDS) were selected. Subgingival plaque and sera were collected and examined for evidence of human periodontitis-associated pathogens. Serum IgG titers were measured by ELISA to multiple strains of Porphyromonas gingivalis, Bacteroides forsythus, Dichelobacter nodosus, Actinobacillus actinomycetemcomitans, Prevotella intermedia, and Fusobacterium nucleatum as well as several purified antigens (cysteine proteases, LPS, K, and fimbriae).

RESULTS

: Neither the organism Aa nor antigens to Aa were found in any animal. Most animals were positive for Pg, Bf, and Pi, but DNA probes detected no difference between HS and PDS relative to amounts of pathogens in subgingival plaque. PDS had significantly higher serum IgG titers to all Pg strains, to 50% of Bf strains, to the Pi and Fn strains, and to fimbriae and the two cysteine proteases (p-values ranging from 0.05 to 0.001). Regression analysis demonstrated a significant association between number of teeth lost and serum IgG antibody titers to whole-cell sonicate antigens of P. gingivalis strains (p<0.01) and body weight (p<0.01).

CONCLUSIONS

: The presence of pathogens associated with periodontitis was reflected in differences in serum IgG titers between healthy and diseased sheep. This may have influenced animal body weight and might have systemic health and economic consequences. The data suggest that susceptible and non-susceptible sheep can be identified for periodontal research.

Oral immunization with recombinant Salmonella typhimurium expressing a cloned Porphyromonas gingivalis hemagglutinin: effect of boosting on mucosal, systemic and immunoglobulin G subclass response

Live avirulent Salmonella typhimurium are convenient vaccine vectors for the delivery of recombinant antigens for the induction of mucosal and systemic immunity. The hagB gene encodes a hemagglutinin of Porphyromonas gingivalis, a suspected causal agent in human adult periodontal disease. In previous studies, we have shown that hagB can be expressed in avirulent S. typhimurium and is immunogenic when given orally to mice. In this study, we evaluated recall responses in both serum and mucosal secretions after boosting. In addition, we have examined the immunoglobulin G (IgG) subclass response in serum to both HagB and the Salmonella carrier. Mice were orally immunized with S. typhimurium expressing the hagB gene and then boosted 14 weeks later. Responses were measured through 27 weeks. Both primary and recall IgG and IgA responses were seen in serum to the purified HagB as well as to the Salmonella carrier. Likewise, mucosal primary and recall responses were seen in saliva, fecal extracts and vaginal washes although the kinetics of the responses differed. The anti-HagB response in serum was dominated by IgG2a during the peak of primary response, prior to boosting and during the peak of the recall response. The anti-S. typhimurium response shifted from predominantly IgG3 following primary immunization to IgG2a after boosting. The IgG1 response was minimal against each antigen. This pattern of IgG subclass distribution is consistent with a Th1-type response. These data indicate that avirulent S. typhimurium is capable of delivering a putative virulence factor from P. gingivalis and inducing a primary and recall response in both serum and secretions and provides a means of studying P. gingivalis virulence factors and for the development of a potential vaccine.

Oral microflora of the ferret at the gingival sulcus and mucosa membrane in relation to ligature-induced periodontitis

The aim of this study was to describe, in the domestic ferret, the composition of the normal gingival sulcus and the near related mucosa microflora and the shift in the composition during an acute periodontal breakdown induced by the placement of ligatures. Five animals were used. At the start of the experiment (day 0) and before the placement of the ligatures, 2 microbiological samples were obtained from the gingival sulcus and the related mucosa at the mid-buccal surface of the right upper P4. The same sites were sampled on the left side, serving as control sites. On day 28, new microbiological samples were taken from the same 4 sites. The samples were analyzed with darkfield microscopy and with viable counts. In the darkfield analysis, on day 0, the predominant bacterial morphotype was cocci, ranging from 88-92%. The viable counts showed that nearly 100% of the total cultivable flora was composed of facultative anaerobic gram-negative and gram-positive rods. Pasteurella spp., Corynebacterium spp. and Rothia spp. were the major components of these bacterial groups. No anaerobic bacteria were detected. On day 28, cocci decreased to approximately 75% in the experimental gingival sulcus sample, and filaments and rods increased significantly. Spirochetes remained largely unchanged during the experiment. The composition of the experimental site samples changed. There was a decrease in the mean numbers of facultative anaerobic gram-positive rods, and approximately one third of the microflora comprised anaerobic gram-negative rods, mainly Porphyromonas gingivalis and Fusobacterium spp. Although the composition of the microflora of the ferret presented few similarities to that described in dogs and monkeys, the anaerobic portion of the gingival sulcus and oral mucosa microflora related to ligature-induced periodontitis presented microorganisms observed in experimental periodontitis both in dogs and monkeys as well as in human periodontal diseases.

Black-pigmented gram-negative anaerobes in periodontitis

Black-pigmented Gram-negative anaerobes have been associated with periodontal disease and tooth loss since they were first isolated by Burdon in 1928. Porphyromonas gingivalis, which is usually not isolated from children, adolescents or adults with no periodontal breakdown, has been recognized as one of the most important periodontopathogens. Its presence is strongly correlated with deep periodontal pockets, which are assumed to be its main habitat. Correlations have been shown also with attachment loss, clinical inflammation and serum antibody levels, indicating an aetiological role in the periodontal disease. Their pathogenicity in animal models resembling periodontal disease is documented. They are frequently isolated from periodontal abscesses. The relationship between Prevotella intermedia and periodontal disease is not clear. It is frequently isolated from advanced periodontitis, often as the only black-pigmented Gram-negative anaerobic species; however, the prevalence in adults with no periodontal breakdown is high. It is found frequently in periodontal abscesses and in acute necrotizing and ulcerative gingivitis. Serogroup I is found predominantly in deep periodontal pockets, whereas all serogroups (I-III) are found in shallow pockets and gingivitis. No conclusive difference in pathogenicity between serogroups has been found. Pr. melaninogenica, Pr. denticola and Pr. loescheii are frequently found in the gingival crevice in preschool children and other age groups with gingivitis, but are seldom found in deep periodontal pockets.

Detection of high-risk groups and individuals for periodontal diseases: laboratory markers based on the microbiological analysis of subgingival plaque

Periodontal microbiology is reviewed with regard to the potential of certain characteristics to serve as markers of high risk groups or individuals for periodontal diseases. The generally accepted associations between particular organisms and the various periodontal diseases are discussed. The usefulness of various clinical study designs is reviewed. The ecology of the subgingival plaque microflora is discussed and a number of suggestions for future research are made. We have concluded that there is no monospecific aetiology to any of the various periodontal conditions. Nevertheless, we give particular attention to the role of the black-pigmented bacteroides based upon our belief that they, and Bacteroides gingivalis in particular, are fundamental to our understanding of the biology of periodontal diseases in humans and other animals. Consequently, the contribution of its various virulence factors and their potential as markers of disease susceptibility and activity is addressed.

Experimental infections by Bacteroides gingivalis in non-immunized and immunized rabbits

The interactions between Bacteroides gingivalis and systemic antibodies were studied in tissue cages implanted in the backs of New Zealand white rabbits. Infectivity was evaluated according to clinical signs and to leukocyte and bacterial counts in material aspirated from the tissue cages. Pre- and post-inoculation antibody levels to sonicated whole bacterial cells were determined by enzyme-linked immunosorbent and agar immunodiffusion assays. Rabbits immunized against B. gingivalis and then challenged with pure cultures of B. gingivalis revealed complete elimination or markedly lower postinoculation bacterial counts and considerably weaker tissue reactions than non-immunized animals. B. gingivalis co-inoculated with Actinobacillus actinomycetemcomitans caused significantly more severe infections than observed in monoinfected animals. The present results suggest that the immune system acting through systemic antibodies and/or cellular mechanisms may modulate the pathogenic potential of infecting periodontal pathogens.

Indicators of periodontal disease activity: an evaluation

It is becoming increasingly apparent that the traditional clinical criteria are inadequate for: determining active disease sites in periodontitis, monitoring quantitatively the response to therapy or measuring the degree of susceptibility to future breakdown. In an attempt to develop objective measures, a wide variety of studies have been undertaken using saliva, blood, plaque and gingival crevicular fluid (GCF) as the specimen source. Examination has included: specific bacteria and their products; host cells and their products (enzymatic and antibacterial, both immunologic and non-immunologic); products of tissue injury derived from local epithelial and connective tissues and bone. Although most of the work to date has failed to provide reliable aids to the clinician, refinements in techniques for sampling and the availability of more sophisticated analytic techniques give cause for optimism. Methods proposed for detection of disease-associated bacteria in subgingival plaque vary in their sensitivity and specificity. Dark field microscopy shows some correlation with existing disease; however, the limited specificity of this method imposes severe restrictions on its usefulness. Highly specific polyclonal and monoclonal antisera to suspected pathogens Bacteroides gingivalis and Actinobacillus actinomycetemcomitans have been developed and improved methods of identification of these microbes in plaque by ELISA immunofluorescence and flow cytometry are under development. With respect to the host response, a strong correlation between antibody patterns to specific bacteria and periodontal disease categories appears to be emerging. Although most studies have focused on serum antibody derived from peripheral blood, a shift to detection of local antibody response appears to be likely. Techniques of measurement that are exquisitely sensitive have been developed for detection of major immune recognition proteins such as antibody and complement in crevicular fluid. Research efforts attempting to correlate local antibody response to local disease activity are underway. Measurement of GCF flow rate, endotoxin, H2S, butyrate and a variety of enzymes (e.g., collagenase, arylsulfatase, B-glucuronidase) show good correlation with levels of gingivitis. In periodontitis, the most promising markers of tissue breakdown are prostaglandins of the E series, the enzymes collagenase and aspartate aminotransferase, sulfated glycosaminoglycans, osteoclastic activating factor and bone resorptive capacity of crevicular cells. Assay of the migration of crevicular leucocytes in vivo can serve as an indicator of a defect in host resistance.(ABSTRACT TRUNCATED AT 400 WORDS)