Porphyromonas-like gram-negative rods in naturally occurring periodontitis in dogs

A total of 259 Gram-negative Porphyromonas-like rods isolated from subgingival plaque samples of 16 family-owned dogs with naturally occurring periodontitis were characterized phenotypically by biochemical reactions, metabolic end products and enzymatic activities (API-ZYMTM, RoscoTM). Four distinct groups were found. Group A isolates (63) were asaccharolytic, lipase negative, trypsin positive and produced phenylacetic acid (PAA) from peptone-yeast extract glucose broth. Unlike P. gingivalis strains they were catalase positive. Group B isolates (42) differed from those of group A by a positive lipase reaction and from those of group D by failing to ferment sugars. Group C isolates (88) were asaccharolytic and did not produce PAA. They were alpha-fucosidase, N-acetyl-beta-glucosaminidase (beta-NAG) and trypsin negative, resembling P. endodontalis, but unlike human isolates, they were catalase positive. Subgroup C.1 isolates (6) differed from those of parent group C by producing minor amounts of PAA, and subgroup C.2 isolates (12) were beta-NAG positive. Group D isolates (46) were weakly fermentative, lipase, catalase and trypsin positive, and produced PAA. They resembled the B (P.) salivosus type strain which, in our hands, fermented weakly glucose, lactose and mannose. Two isolates could not be assigned to any of the previous groups.

Non-radioactively labelled DNA probes for the detection of periodontopathogenic Prevotella and Porphyromonas species

Digoxigenin-labelled synthetic DNA probes directed against the 16S rRNA were used for the direct detection of the periodontopathogenic bacteria Prevotella intermedia and Porphyromonas gingivalis in subgingival plaque by applying a DNA-RNA dot-blot hybridization procedure. The test was evaluated with 134 plaque samples from 26 patients with adult periodontitis or rapidly progressive periodontitis. The lower limit of detection was 10(4)-10(5) bacteria/specimen. A semiquantitative assessment of the two species in each sample and in the corresponding periodontal site was achieved by this technique. It is possible to examine 80-90 samples within two days with low material costs.

Fluorescence in situ hybridization for direct visualization of gram-negative anaerobes in subgingival plaque samples

Fluorescent oligonucleotide probes complementary to variable regions of Porphyromonas gingivalis and Bacteroides forsythus 16S ribosomal RNA were used to identify these organisms in smears of formaldehyde-fixed subgingival plaque samples from patients suffering from periodontitis. Fluorescence in situ hybridization represents a useful method for assessing the microbial ecology of the periodontal flora.

Occurrence of Porphyromonas gingivalis with Prevotella intermedia in periodontal samples

To further examine the previously suggested inverse relationship between Porphyromonas gingivalis and Prevotella intermedia in periodontal disease, 1016 samples taken from single or multiple (pooled) subgingival sites were cultured anaerobically and examined for the simultaneous occurrence of the microorganisms. P. gingivalis was isolated from 297 (29%) and Pr. intermedia from 501 (49%) samples. P. gingivalis was found as frequently with (14%) as without (15%) Pr. intermedia. The type of sampling had no effect on the occurrence of P. gingivalis with Pr. intermedia. However, female subjects harboured them in combination more frequently than male subjects. The mean proportions of P. gingivalis in the cultivable flora appeared to be lower when found with than without Pr. intermedia. Whether the detection of the combination, or P. gingivalis alone, has clinical relevance needs further clarification.

Occurrence of plasmids in black-pigmented gram-negative anaerobes

Black-pigmented Gram-negative anaerobes are causative agents of pyogenic infections and are closely linked to various forms of periodontal diseases. Whereas many studies have shown a high incidence of plasmids in intestinal Bacteroides spp., there have been only a few reports of plasmid analyses in pigmented Gram-negative anaerobes. According to previous reports and confirmed in this study, plasmids can be present in Porphyromonas asaccharolytica, Prevotella intermedia, Pr. melaninogenica, and B. levii but have not been detected in P. gingivalis or other black-pigmented species. There were no correlations between plasmids and phenotypes such as resistance to antibiotics or bacteriocinogenicity. The highest carriage rate was found in isolates from cases of chronic otitis media, but the relationship between this site of infection and a high incidence of plasmids could be incidental. The size of plasmids ranged from 1.5 to 29 MDa. Plasmids with molecular weight > 10 MDa were described for the first time in these organisms. Repeated plasmid analyses showed that the plasmid patterns were generally stable.

Pigmented Prevotella species in the periodontally healthy oral cavity

Pigmented Prevotella spp. have been connected with oral infections as well as being part of the healthy gingival flora. The aim of this study was to determine the presence of pigmented Prevotella spp. in saliva and gingival crevice samples from periodontally healthy adults. Twelve Caucasian female subjects (mean age 28 years, range 21-36 years) with no pockets > or = 4 mm, nor bleeding after probing were selected for this study. Paraffin-stimulated saliva was collected first; then, a pooled subgingival bacterial sample was taken with a sterile curette from mesiobuccal surfaces of all first molars. The samples were inoculated on to non-selective and selective media and incubated anaerobically. The most frequent species isolated were Pr. melaninogenica, Pr. intermedia and Pr. loescheü, found in 11, ten and nine subjects, respectively. The mean percentage of the total cultivable anaerobic microflora in salivary/subgingival samples were 14.7/0.6 for Pr. melaninogenica, 3.1/5.3 for Pr. intermedia and 2.6/1.2 for Pr. loescheii. Pr. denticola was found in one saliva sample and Pr. corporis, in two subgingival samples only. The number of different pigmented Prevotella spp. in the same mouth was 2-4 (mean 2.75). In conclusion, Pr. melaninogenica, Pr. intermedia and Pr. loescheii seem to be common microorganisms in the periodontally healthy oral cavity.

Black-pigmented gram-negative anaerobes in endodontic infections

Necrotic dental root canal infections are polymicrobial infections dominated by anaerobic bacteria. The number of different species in one canal is usually low, approx. 4-7 species. The species isolated most frequently belong to the genera Prevotella, Porphyromonas, Fusobacterium, Peptostreptococcus, Eubacterium and Streptococcus. The frequency of isolation of black-pigmented Gram-negative anaerobes in endodontic infections varies from 25% to > 50%. Pr. intermedia is the most commonly found pigmented species, followed by Pr. denticola and two Porphyromonas species, P. gingivalis and P. endodontalis. Several studies have shown that P. gingivalis and P. endodontalis are closely related to the presence of acute symptoms in endodontic infections, whereas other black-pigmented Gram-negative anaerobes are not. However, several other species may also be involved in acute infections. Moreover, Porphyromonas species have occasionally been isolated from cases with no symptoms. Although Porphyromonas spp. are clearly related to symptoms at the beginning of therapy, they are not important for the prognosis of the treatment.

The presence of black-pigmented gram-negative anaerobes in the oral cavity of edentulous subjects

The aim of this study was to investigate whether black-pigmented Gram-negative anaerobes are part of the indigenous oral flora of edentulous subjects with or without dentures. Group I consisted of 11 subjects with dentures (mean age 63.6 years, range 52-75) and Group II consisted of 39 subjects with complete dentures in both jaws (mean age 59.3 years, range 37-80). Two microbial samples for microbiological examination were taken from each subject. One of them was from the dorsum of the tongue and the other was from saliva. Black-pigmented Gram-negative anaerobes > 10(7) cfu/ml were found in both samples. In 50 edentulous subjects, they were found more commonly from tongue (40%) than from saliva (26%). None of the subjects had Porphyromonas gingivalis. There was no statistically significant difference (P > 0.05) between the presence of black-pigmented Gram-negative anaerobes on tongue and in saliva in the two groups. Our results suggested that high levels of black-pigmented Gram-negative anaerobes may belong to the indigenous oral flora in edentulous mouths with or without dentures.

Relationship between oral gram-negative anaerobic bacteria in saliva of the mother and the colonization of her edentulous infant

Various gram-negative anaerobic bacterial species can be detected in the oral flora of edentulous infants. However, knowledge of the initial infection source is still scarce. Thirty Caucasian mothers (mean age 30 years) and their edentulous infants (mean age 3 months) were examined for the possible similarity of the oral gram-negative anaerobic flora. Paraffin-stimulated saliva was collected from the mothers. A pooled swab sample from mucosal surfaces and unstimulated saliva were collected from the infants. The samples were inoculated on nonselective and selective media and cultured aerobically and anaerobically. All of the 30 mothers harbored Fusobacterium nucleatum and 29 mothers Prevotella melaninogenica in their saliva. The salivary levels of P. melaninogenica, F. nucleatum, nonpigmented Prevotella spp., Prevotella intermedia and Prevotella loescheii exceeded 10(4) CFU/ml in about half of the 30 mothers. At this maternal salivary level, the infants' colonization frequency of P. melaninogenica and F. nucleatum was doubled. A positive correlation between maternal salivary concentration and infant's colonization was found for P. melaninogenica. No positive association was found with nonpigmented Prevotella spp., P. intermedia and P. loescheii. It can be speculated that maternal saliva may act as a source of some gram-negative anaerobes in the oral microflora of edentulous infants as early as before tooth eruption.

Detection and identification of Mobiluncus species by direct filter hybridization with an oligonucleotide probe complementary to rRNA

A hybridization assay for direct detection and identification of Mobiluncus species has been developed and tested. A [32P]-labelled synthetic oligonucleotide probe, complementary to a nucleotide sequence in the variable region V8 of Mobiluncus 16S ribosomal RNA, was utilized. One of the advantages of using rRNA as target molecule for the hybridization assays is the copy number of rRNA, which can be as high as 10(4), and that additionally three to six sites on the minus strand of the DNA gene can be utilized. This probe was found to be sensitive and to react with 62 of 68 tested typical or atypical Mobiluncus isolates. It was also specific, and was shown not to react with 96 tested unrelated bacterial species and isolates, including taxonomically closely related species like Actinomyces or Bifidobacterium spp., or with bacteria isolated from the vagina of both healthy persons with an undisturbed flora, as well as from patients suffering from the bacterial vaginosis syndrome (BV).

Enumeration of subgingival species on primary isolation plates using colony lifts

This study evaluated the feasibility of using a colony lift method and DNA probes to enumerate bacterial species cultured on primary isolation plates. Fourteen digoxigenin-labeled whole chromosomal DNA probes representing 12 subgingival species were validated by hybridization with colony lifts prepared from 249 reference strains of 51 species grown on Trypticase soy agar plates supplemented with 5% sheep blood. Colonies of reference strains were lifted onto Nytran filters from plates and treated to lyse cells, remove cellular proteins, denature and fix microbial DNA to the filters. Positive reactions were detected with an anti-digoxigenin antibody conjugated to alkaline phosphatase and revealed by bromo-chloro-indolyl phosphate and nitroblue tetrazolium. Cross-reactions were not observed for 13/14 probes, but 2 strains of Streptococcus mitis reacted with the probe to Streptococcus sanguis II. Subgingival plaque samples were taken by means of a sterile curette from mesiobuccal surfaces of teeth present in each of 26 subjects with differing periodontal disease states. Samples were dispersed, diluted, plated and incubated anaerobically for 7 d at 35 degrees C. Colonies were lifted as described above. Filters were cut into sections and hybridized with the 14 digoxigenin-labeled DNA probes. The probes were used to enumerate the test species and the total number of isolates was determined in 711 plaque samples. The colony lift method and DNA probes provided a sensitive, economical and quantitative method for enumerating cultivable microbial species in subgingival plaque samples. In addition, the amplification provided by growing the organisms on agar plates facilitated determination of numbers of organisms in small plaque samples, such as those from healthy sites.

DNA base composition, aerotolerance and enzyme patterns of Leptotrichia buccalis

The guanine plus cytosine content of the DNA of Leptotrichia buccalis varied from 28.4 to 29.5 mol% (three strains). Eleven strains examined grew well under anaerobic and microaerobic conditions, but slowly in air in the presence of CO2. When examined for preformed enzymes in the APIZYM Complete Research Kit, positive reactions were obtained for several glucosidases and carboxylic ester hydrolases, and for a few peptidases.

Identification of Selenomonas species by whole-genomic DNA probes, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, biochemical tests and cellular fatty acid analysis

Nonisotopic, whole-genomic DNA probes, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), biochemical tests in microtiter trays and cellular fatty acid (CFA) analysis were compared for the identification of 5 oral Selenomonas species. DNA probes were prepared by biotin-labeling DNA extracted from the type strains of Selenomonas noxia, Selenomonas flueggei, Selenomonas artemidis, Selenomonas infelix and Selenomonas sputigena. The probes were hybridized with DNA from 21 reference strains, 18 fresh isolates of Selenomonas species, and 21 strains of other oral gram-negative species. Target DNAs were obtained by in situ extraction of colonies blotted onto filter paper. Streptavidin-linked alkaline phosphatase was used to detect homologous reactions of probe and target DNA. Each Selenomonas species DNA probe reacted with reference strains of only that species. All Selenomonas strains that reacted with the DNA probe for a particular species gave similar biochemical test results, SDS-PAGE protein profiles, and CFA profiles to those of the type strain of the corresponding species. All the methods tested were useful for identifying the species, and all yielded similar identifications of the fresh isolates. The DNA probes, however, had the potential for identifying Selenomonas species directly from primary isolation plates or plaque samples.

Metronidazole in periodontitis: reduced need for surgery

A considerable amount of circumstantial evidence indicates that most forms of periodontitis are due to the presence or dominance of a finite number of bacterial species in the subgingival plaque. Almost all of the putative pathogens are anaerobic species, indicating that most forms of periodontitis could be diagnosed as anaerobic infections. In this double-blind investigation, patients with elevated proportions or levels of spirochetes in 2 or more plaque samples, i.e., 60% spirochetes, were randomly assigned to receive either metronidazole, 250 mg 3 x a day for 1 week, or placebo (positive-control) after the completion of all debridement procedures. When the patients were re-examined 4 to 6 weeks later, the patients in the metronidazole group (n = 15) exhibited a highly significant (p less than 0.01) reduction in probing depth and apparent gain in attachment levels relative to the patients (n = 18) in the positive-control group about those teeth that initially had probing depths of 4 to 6 mm. This pattern was also observed about teeth that initially had probing depths greater than or equal to 7 mm. This reduction in probing depths and apparent gain in attachment was associated with a significant reduction in the need for periodontal surgery in the metronidazole-treated patients (difference 8.4 teeth per patient) compared to the positive-control patients (2.6 teeth per patient). These clinical improvements in the metronidazole group were associated with significantly lower proportions of spirochetes, selenomonads, motile rods, and P. intermedius, and a significantly higher proportion of cocci in the plaques. These findings indicate that systemic metronidazole, when given after all the root surface debridement is completed, leads to additional treatment benefits, including a reduced need for surgery, beyond that which can be achieved by debridement alone.

Putative periodontopathogens in “diseased” and “non-diseased” persons exhibiting poor oral hygiene

The aim of the study was to assess the occurrence of some putative periodonto-pathogens in "test" and "control" sites in "diseased" and "non-diseased" persons, respectively, from an adult rural Kenyan population exhibiting poor oral hygiene and widespread loss of attachment (LA). 14 persons (less than 35 years) were assigned to a "diseased" category on the basis of at least 4 sites with LA greater than or equal to 4 mm; at least 5 mm LA and a pocket greater than or equal to 4 mm interproximally in a lower incisor ("test" site): and less than 2 mm LA and no pocket greater than or equal to 4 mm distal to a lower canine or mesial to a lower first premolar ("control" site). Age-matched "non-diseased" persons were identified on the basis of no sites with LA greater than 2 mm and no pockets greater than or equal to 4 mm associated with LA. Paperpoint samples from test and control sites as well as a scraping sample from the dorsum of tongue were examined for presence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Bacteroides intermedius, B. melaninogenicus group, Capnocytophaga, Selenomonas spp., and Wolinella recta. P. gingivalis was found in 79% of test sites and 36% of control sites in "diseased" persons, and in 18% and 35% of test and control sites, respectively, in "non-diseased" persons. "No other bacterial group discriminated significantly between test and control sites or between diseased and non-diseased subjects. The surprisingly high occurrence of P. gingivalis in non-diseased subjects, both subgingivally and on tongue, indicates that deep periodontal pockets are not prerequisite ecological environments for P. gingivalis establishment.

Toothbrushing and transient bacteremia in patients undergoing orthodontic treatment

This study was made to determine whether and to what extent bacteremia occurred after toothbrushing in patients undergoing orthodontic treatment with fixed appliances. Twenty patients were selected, all with negative history of heart or hematologic disorders. These patients had not taken antibiotics or had a history of a cold in the previous 30 days. Blood samples of 20 ml were drawn before and 5 minutes after brushing. The immune status of the patients was tested by measurement of isohemagglutins and immunoglobulin levels. Blood samples were incubated in paired culture bottles containing trypticase soy broth (TSB) with an agar paddle and Columbia broth. All samples taken before brushing were negative for bacteria. Five of the 20 patients (25% of the sample) had positive blood tests after brushing. Both anaerobic and aerobic bacteria were identified from the blood samples. Those patients who were found to have a bacteremia did not display poor oral hygiene.

Leptotrichia buccalis bacteremia in patients with cancer: report of four cases and review

Leptotrichia buccalis, an anaerobic gram-negative rod, is part of the normal oral flora and has rarely been isolated from clinical material. We describe four patients with neutropenia and progressive malignancy who had symptomatic L. buccalis bacteremia, and we review an additional four cases from the literature. The mean age of the patients was 31 years (range, 7-73 years), with an equal number of males and females. The number of positive blood cultures in each case ranged from one to four (mean, two); these cultures became positive after 48-120 hours (median, 54 hours). All tested isolates were sensitive to the beta-lactam agents, clindamycin, tetracycline, and metronidazole; five of seven were sensitive to chloramphenicol; and not one was sensitive to the aminoglycosides, vancomycin, ciprofloxacin, or erythromycin. Seven patients had one or more possible portals of entry for bacteremia, including mucositis (four patients), mucositis plus esophageal lesions (two), and possible mucositis plus diverticulitis (one). L. buccalis should be considered a potential pathogen in neutropenic patients, especially when breaks in the mucosal breaks in the mucosal barriers are present.

Associations between six DNA probe-detected periodontal bacteria and alveolar bone loss and other clinical signs of periodontitis

The purpose of the present study was to assess the associations between the presence and amounts of Actinobacillus actinomycetemcomitans, Bacteroides gingivalis, B. intermedius, Eikenella corrodens, Wolinella recta, and Fusobacterium nucleatum in the periodontal pocket and the degree of alveolar bone loss and other clinical signs of periodonitis, such as probing pocket depth, attachment level, and presence of bleeding on probing at the same site. The study material comprised 16 subjects with or without approximal sites showing longitudinal alveolar bone loss who were selected from a group of 142 subjects monitored radiographically over the past 4 years. In this group 105 sites were examined, of which 58 showed recent alveolar bone loss greater than or equal to 1 mm. Subgingival plaque was collected with absorbent paper points and hybridized with 32P-labeled DNA probes specific for the above-mentioned bacteria. The amount of each bacterial species was correlated with the degree of bone loss over time and the three clinical measurements by means of Spearman rank correlation. A. actinomycetemcomitans showed poor correlations with all three clinical signs of periodontal inflammation, whereas B. gingivalis and W. recta demonstrated significant positive correlations with the three clinical measurements and with attachment level and pocket depth, respectively. In addition, the amount of A. actinomycetemcomitans, B. gingivalis and W. recta showed significant positive correlation with the extent of alveolar bone loss at the site. In contrast, the amounts of B. intermedius, E. corrodens, and F. nucleatum showed negative correlations with all four measurements.(ABSTRACT TRUNCATED AT 250 WORDS)

Surface characteristics of Wolinella recta ATCC 33238 and human clinical isolates: correlation of structure with function

Selected characteristics of the surface of Wolinella recta ATCC 33238 and three W. recta clinical isolates (CI) were studied as well as the adherence of these strains to human gingival fibroblasts (HGF). W. recta ATCC 33238 and the CI were examined by electron microscopy, electrophoresis, isoelectric focusing, and adherence to HGF. Electron microscopic examination of CI revealed the presence of a periodic paracrystalline layer external to and associated with the outer membrane. This surface layer (S layer) was not observed on ATCC 33238. Whole cells and outer envelope protein profiles of the CI revealed major bands of 159- to 138-kilodalton proteins which were barely detectable in ATCC 33238. Repeated in vitro subculturing of the CI on solid or liquid medium resulted in both the physical loss of this layer and the loss of the high-molecular-weight proteins. Low-passage-number CI demonstrated 40 to 60% less adherence to HGF than ATCC 33238. These observations suggest that short term in vitro-subcultured W. recta strains possess surface characteristics which are significantly different from those of their long-term in vitro-subcultured counterparts. These differences may have significant effects on host cell interactions.

Monoclonal antibodies for the detection of 'periodontopathic' bacteria

The development of indirect immunofluorescence assays using MAbs as specific probes has made it possible to detect a variety of suspected periodontal pathogens in subgingival plaque, with exquisite sensitivity. The studies demonstrate high reproducibility of the results if different MAbs are used to assess the same bacterial species. Bacteroides forsythus, Bact. gingivalis, Bact. intermedius and Wolinella recta, but not Actinobacillus actinomycetemcomitans were found in sites of adult periodontitis with high prevalence but quite distinct degrees of colonization. The colonization levels of Bact. forsythus and Bact. gingivalis were significantly associated with the probing depth of the lesions. The investigations demonstrate the usefulness of serological analysis of plaque and indicate that several of the organisms implicated in the aetiology of periodontal diseases may be tolerated in high numbers in subgingival lesions, without periodontal destruction.

Capnophilic and anaerobic bacteremia in neutropenic patients: an oral source

The currently accepted empiric antibiotic therapy for bacterial infections in neutropenic patients may not cover the possibility of capnophilic and anaerobic bacteremia. Many of these infections develop in patients with severe mucositis or periodontitis, and the type of organisms recovered also suggests an oral source of infection. We present two cases of bacteremia in neutropenic patients who had been empirically treated with ceftazidime and piperacillin plus amikacin. In the first case a beta-lactamase-producing strain of Capnocytophaga ochracea was isolated; in the second case bacteremia was due to a mixture of Leptotrichia buccalis and Fusobacterium nucleatum. These observations emphasize the necessity for a reevaluation of the possible use of antimicrobial agents active against beta-lactamase-producing capnophilic organisms and anaerobic bacteria during empiric therapy in neutropenic patients with an oral source of infection.

Effect of 0.12% chlorhexidine on bacterial recolonization following periodontal surgery

Bacterial plaque accumulation following periodontal surgery has been directly associated with delayed and altered surgical wound healing. Successful antimicrobial treatment following periodontal surgery depends upon the elimination and suppression of wound associated microorganisms. Highly effective antimicrobials should also prevent recolonization of periodontopathogens. In this investigation, the antimicrobial effect of a 0.12% chlorhexidine gluconate mouthrinse (Peridex) on bacterial recolonization after periodontal surgery was determined. A double-blind, randomized, placebo-controlled study was carried out on 40 patients for 6 weeks. Patients with moderate periodontitis (AAP Class III) underwent osseous periodontal flap surgery in one quadrant. Subgingival and marginal plaque samples from the surgery area were taken prior to surgery and 2 and 6 weeks postoperatively. General descriptive bacteriological cultural analysis and assays for specific microbial populations were carried out. During the 6 weeks of mouthrinse use, patients using chlorhexidine had significant reductions over placebo (P less than 0.05) in the number of total Gram-positive facultative cocci, streptococci (85.8%); Gram-positive facultative rods, primarily Actinomyces (91.7%); Capnocytophaga (97.6%) and Gram-negative anaerobic rods (94.5%). Few black pigmented Bacteroides or Actinobacillus actinomycetemcomitans were found prior to surgery or any time postoperatively. In the chlorhexidine group, 6 weeks post surgery, streptococci were the predominant bacterial group in the sampled plaque. Quantitatively, the distribution of bacteria, after 2 and 6 weeks of mouthrinse use, was consistent with a young, less mature plaque. A previous study demonstrated that this plaque was associated with clinical health.