bluuebunny/crossref_metadata_2025 huggingface dataset:
Prevalence of mutans streptococci in one‐year‐old children
Authors: Grindefjord Margaret , Dahllöf Göran , Wikner Sune , Höjer Bengt , Modéer Thomas
Published: December 2007

Colonization with mutans streptococci was studied in 1095 1‐year‐old children living in suburban Stockholm. During a scheduled vaccination appointment at a child health centre, a bacterial sample was obtained from the child's tongue and a structured questionnaire was completed by the accompanying parent. Six percent of the subjects were colonized with mutans streptococci. The variables most strongly correlated with presence of mutans streptococci were: non‐Swedish background, consumption of sugar‐containing beverages at night and total consumption of sugar‐containing beverages. The results indicate that, by the age of 1 year, maternally influenced behaviour patterns such as dietary habits that may predispose to early colonization of mutans streptococci are already established. Such early colonization with mutans streptococci may predict high caries risk in the primary dentition.
Effect of delmopinol on in vitro dental plaque formation, bacterial acid production and the number of microorganisms in human saliva
Authors: Simonsson T. , Hvid E. B. , Rundegren J. , Edwardsson S.
Published: December 2007

This study investigated the effect of surface active compound, delmopinol, on plaque formation and established plaque in vitro, on the bacterial acid production from glucose and on the total viable bacterial counts in saliva. The antimicrobial effect was compared with that of chlorhexidine. The plaque‐inhibiting effect was evaluated in an artifical mouth system, and the effect on bacterial acid production was registered as decrease of pH in bacterial suspensions with various concentrations of delmopinol. It was shown that delmopinol is able to prevent plaque formation, to dissolve established plaque in vitro, and that it has 5–125 times higher minimum inhibitory concentrations than chlorhexidine. Saliva samples collected 1 min after rinsing with delmopinol showed on differences in the total number of bacteria in saliva as compared with controls. It was also shown that the bacterial acid production from glucose was reduced successively with increasing concentrations of delmopinol. The results indicate that delmopinol might be as effective as chlorhexidine against plaque formation and that delmopinol is capable of penetrating established plaque, thus promoting more effective mechanical cleansing.
Predominant cultivable flora in pericoronitis
Authors: Wade W. G. , Gray A. R. , Absi E. G. , Barker G. R.
Published: December 2007

The predominant cultivable flora in pericoronitis was investigated by culturing pus from affected sites in 20 patients. Twenty colonies were picked at random from non‐selective plates and identified using conventional biochemical and physiological tests, analysis of metabolic end‐products by gas chromatography and protein profile analysis. The most frequently isolated organisms were Prevotella (Bacleroides) intermedia, Peptosireptococcus micros, Veillonella species, Fusobacterium mucleatum and Streptococcus mitis. Porphyromonas (Bacleroides) gingivalis was not isolated and asaccharolytic Eubacterium species were virtually absent. The predominant cultivable microflora in pericoronitis was found to be highly anaerobic in nature and superficially similar to that found in chronic periodontitis, although proposed marker orgnisms of severe periodontitis were absent.
Enumeration of subgingival species on primary isolation plates using colony lifts
Authors: Gunaratnam M. , Smith G. L. F. , Socransky S. S. , Smith C. M. , Haffajee A. D.
Published: December 2007

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°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.
Mechanisms of aggregation accompanying morphogenesis in Candida albicans
Authors: Holmes Ann R. , Cannon Richard D. , Shepherd Maxwell G.
Published: December 2007

Cultures of Candida albicans yeast cells do not normally aggregate, but extensive aggregation accompanies the induction of mycelial growth, indicating the occurrence of cell surface changes during the yeast to mycelial transition. Aggregation correlated with the formation of germ tubes as did changes in surface charge determined by attachment to ion exchange sepharose beads. Yeast cells of all strains examined were negatively charged and attachment to positively charged (DEAE) sepharose beads increased following germ tube formation. If Mg2+ was present during germ tube formation, a high degree of clumping occurred that could only be dispersed by treatment with protein‐disrupting agents. Trypsin, chymotrypsin, SDS, urea, guanidine HC1 and dithiothreitol but not EDTA or EGTA caused irreversible dispersal of aggregates, although germ tube aggregates dispersed by treatment with buffers at high pH reaggregated if neutralized or if calcium ions were added. Germ tube cultures produced in divalent cation‐deprived medium formed aggregates that were readily dispersed by washing. However, the addition of Mg2+ or other divalent cations (Ca2+, Zn2+, Cu2+, Fe2+) caused immediate aggregation of these cultures. These results suggest that divalent cation crossbridging between opposing anionic sites and protein interactions act synergistically to promote aggregation of C. albicans germ tube cells.
Inhibition of Actinomyces viscosus – Porphyromonas gingivalis coadhesion by trypsin and other proteins
Authors: Ellen R. P. , Song M. , Buivids I. A.
Published: December 2007

Protease activity is associated with the coadhesion of Actinomyces viscosus and Porphyromonas gingivalis. To try to distinguish whether the recognition/adhesion or degradative functions of proteases are more crucial for coadhesion, we determined the effect of trypsin and other purchased proteases and proteins on coadhesion when they were incorporated in the coadhesion assay buffer or when A. viscosus cells were pretreated with trypsin. Coadhesion was measured by the decrease in turbidity caused by the absorption of A. viscosus cells from aqueous suspension by P. gingivalis‐coated hexadecane droplets. Pretreatment of A. viscosus with trypsin had no obvious effect on the kinetics of coadhesion. Likewise, trypsinization of A. viscosus failed to aid or enhance coaggregation by chemically induced, trypsin activity‐deficient mutants of B. gingivalis. In contrast, incorporating trypsin in the buffer during the coadhesion assay yielded a concentration‐dependent inhibition of coadhesion greater than the inhibition found with the same concentration of other proteases. Coadhesion was also impaired to a greater extent by similar wt/vol concentrations of nonproleolytic proteins (bovine serum albumin (BSA), defatted BSA, gelatin, and casein), by antisera against whole P. gingivalis cells and fimbriae, by preimmune serum, and by the amino acid arginine but not lysine. These findings suggest that the role of proteases in coadhesion is not solely to enzymatically “prime” A. viscosus for more avid coadhesion and that their role as potential protein or peptide seeking adhesins should be considered.
Comparative mitogenicity and polyclonal B cell activation capacity of eight oral or nonoral bacterial lipopolysaccharides in cultures of spleen cells from athymic (nu/nu‐BALB/c) and thymic (BALB/c) mice
Authors: Sveen K. , Skaug N.
Published: December 2007

Optimal stimulatory doses of purified phenol‐water extracted lipopolysaccharides (LPS) from 5 selected strains of 3 putative periodontopathogens (Fusobacterium nucleatum, Prevotella intermedia, and Veillonella), 3 strains of 2 nonoral bacterial species (Bacteroides fragilis and Salmonella enteritidis), and pokeweed mitogen (PWM)induced significantly higher maximum mitogenic responses and polyclonal Ig production in cultures of unfractionated spleen cells from nu/nu/‐BALB/c (nude) than from BALB/c (normal) mice. Compared with PWM, the LPS were stronger mitogens showing relative mitogenic capacities: B. fragilis LPS> F. nucleatum LPS> S. enteritidis LPS, Veillonella LPS, and P. intermedia LPS. B. fragilis LPS was the most and S. enteritidis LPS the least effective polyclonal B cell activator of total Ig, IgG2a, IgG2b, IgG3, IgA, and IgM secretion. IgGl was not detected. P. intermedia LPS was the strongest IgA inducer. Kinetic observations indicated mitogenic responses and polyclonal B cell activation in a close sequential order in nude and normal cells. The LPS were potent Ag‐ and T cell‐independent polyclonal B cell activators and LPS of subgingival plaque bacteria may therefore play a nonspecific role in the pathogenesis of periodontal diseases.
The differential effects of polymorphonuclear leukocyte secretion on human natural killer cell activity
Authors: Lala A. , Lindemann R. A. , Miyasaki K. T.
Published: December 2007

We studied the differential effects of polymorphonuclear leukocyte (PMN) secretion on human natural killer cell (NK) and lymphokine‐activated killer cell (LAK) activity. Supernatant fluids from PMN stimulated by serum‐opsonized zymosan (SOZ), n‐formylmethionylleucylphenylalanine (FMLP) and interleukin‐8 (1L‐8) were incubated with peripheral blood lymphocytes (PBL) for 1 d and 4 d. Supernates from unstimulated PMN and PMN induced by FMLP and IL‐8 decreased NK and LAK cytotoxicity in a dose‐dependent fashion against K562 and M14 targets, respectively. Only the suppression caused by supernates from unstimulaled PMN was ablated by incubation of PMN with indomethacin. Secretions from PMN stimulated by SOZ increased both NK and LAK cytotoxicity and induced PBL proliferation synergistically with IL‐2. This enhancing factor was heat‐labile, nondialyzable (MWCO 3500), and not blocked by anti‐inter‐feron‐y. Anaerobic conditions did not influence the modulatory activity of PMN supernates, indicating that oxygen metabolites were not involved. We conclude that PMN release factors that modulate in vitro NK and LAK activities.
Microbiological evaluation of periapical infections in Egypt
Authors: Wasfy M. O. , McMahon K. T. , Minah G. E. , Falkler W. A.
Published: December 2007

This study identifies and correlates proportions of bacteria in periapically involved anterior teeth of 85 adult Egyptian patients. Affected sites were free from caries and periodontal disease but had a history of trauma. The mean number of component bacterial species per specimen was 3.1. Anaerobic bacteria were the dominant flora present in specimen cultures, comprising 73% (190/259) of cultivable bacteria. The most frequently isolated organisms were Eubacterium species (68%), black‐pigmented Bacteroides (56%), Streptococcus morbillorum (47%) and non‐pigmented Bacteroides (37%). These organisms also showed the highest proportional values relative to total cultivable bacteria. The mean percentages of total viable counts of these isolates were 19.0%, 14.1%, 18.0% and 15.5%, respectively. Statistical analysis of data revealed a significant negative correlation between S. morbillorum and Bacteroides species.
Pathogenicity of Actinomyces israelii and Arachnid propionica: experimental infection in guinea pigs and phagocytosis and intracellular killing by human polymorphonuclear leukocytes in vitro
Authors: Figdor D. , Sjögren U. , Sörlin S. , Sundqvist G. , Nair P. N. R.
Published: December 2007

Strains of Actinomyces israelii and Arachnia propionica, isolated from clinical cases of failed endodontic therapy, were examined for: (i) their ability to survive and establish themselves in the soft connective tissue that grew into subcutaneously implanted tissue cages in guinea pigs; (ii) cell‐surface hydrophobicity; and (iii) phagocytosis and killing by human polymorphonuclear leukocytes (PMNs) under aerobic and anaerobic conditions. Bacteria were inoculated into the tissue cages in guinea pigs and the cage contents were retrieved after 1, 7, 14 and 21 d for culturing and light and electron microscopy. Both bacterial species showed substantial decline in the number of bacteria by day 7 after the inoculation. Thereafter, the A. israelii strain recovered and, by day 21, had started to increase in number. Light and electron microscopy revealed the formation of typical actinomycotic colonies. A. propionica, on the other hand, continued to decline in number during the entire period of experimental infection and did not form colonies. Both strains were hydrophobic, readily phagocytosed and were efficiently killed by human PMNs under aerobic and anaerobic conditions in vitro. These results suggest that the pathogenicity of A. israelii is due to its ability to establish characteristic cohesive colonies consisting of branching filamentous organisms that are enmeshed in an extracellular matrix. It seems that the organisms existing in such colonies can collectively evade destruction and elimination by host phagocytic cells, whereas in vitro suspensions of the bacteria are easily phagocytosed and efficiently killed by PMNs. With respect to A. propionica, further investigations are necessary to understand its pathogenicity.
Chronic peroral immunization of conventional laboratory rats with mutans streptococci leads to stable acquired suppression of salivary antibodies
Authors: Riviere G. R. , Wagoner M. A. , Freeman I. L.
Published: December 2007

Prior investigations have demonstrated that salivary antibody responses to mutans streptococci are dose‐dependent and temporary. The purpose of this study was to evaluate the stability of antibody suppression established by mutans streptococci. Streptococcus mutans 6715‐15 was provided in food to conventional rats for 18 weeks. Antigen was withdrawn for 10 weeks and then resumed for an additional 6 weeks. Saliva and serum from nonimmunized controls and from experimental rats were tested with a quantitative enzyme‐linked immunosorbent assay for IgA and IgG antibodies to whole bacterial cells and to soluble antigen. Results show that salivary antibodies were stimulated by primary peroral immunization, that IgA was the dominant isotype and that IgA antibodies were primarily directed against soluble antigen. This study also shows that immunity is not maintained, even while challenge continues, and that once suppression is established, immunized animals do not recover their ability to respond, even if exposure is stopped for 10 weeks before re‐exposure.
Mechanism of water‐insoluble glucan synthesis in Streptococcus sobrinus
Authors: Takehara T. , Ansai T. , Yamashita Y. , Itoh‐Andoh M. , Hanada N. , Kunimori A.
Published: December 2007

Synthesis of water‐insoluble glucan (IG) by 1,3‐α‐D‐glucan synthase from Streptococcus sobrinus was examined using methylalion analysis. The purified enzyme was incubated with sucrose and dextran T2000 (DT2000) for a given time and only IG was harvested by centrifugation. The remaining supernatant was incubated again, and IG was obtained. By repeating the above method using the residual supernatant, we obtained 5 varieties of IG precipitated in different periods. These IGs were methylated and examined using gas chromatograph mass spectrometry. The DT2000 water‐insolubilized in the early reaction stage tended to have a highly ramified structure, with 1,3‐α‐D‐glucan on a 1,6‐α‐D‐glucan chain as the main chain. On the contrary, the DT2000 water‐insolubilized in the late stage tended to have sparse side chains of 1,3‐α‐D‐glucan which elongated with incubation. Specifically, the greater the number of side chains, the sooner the DT2000 was insolubilized. These results suggest that water‐insolubilization of the water‐soluble glucan not only depends on the increase of the ratio of 1,3‐α‐glucoside linkages to 1,6‐α‐glucoside linkages but also on the degree of branching of the 1,3,6‐α‐branched glucoside linkages.
Stimulatory effect of bicarbonate on the glycolysis of Actinomyces viscosus and its biochemical mechanism
Authors: Takahashi N. , Yamada T.
Published: December 2007

The effects of bicarbonate on acid production by 4 human strains of Actinomyces viscosus were estimated under anaerobic conditions. The rate of acid production was accelerated by bicarbonate 3‐4‐times as much as that without bicarbonate. The analyses of intracellular glycolytic intermediates, NAD and NADH revealed a decrease in NADH:NAD ratio and an increase in the level of 3‐phosphoglycerate in the cells when bicarbonate was present. Furthermore, when bicarbonate was available, malate dehydrogenase and fumarate reductase in the succinate pathway were expected to function as NADH‐oxidizing enzymes in addition to lactate dehydrogenase. These observations indicate the efficient regeneration of NAD in the presence of bicarbonate. Thus, the stimulation of A. viscosus glycolysis by bicarbonate was thought to stem from the activation of glyceraldehyde 3‐phosphate dehydrogenase (G3PDH) by the decrease in the level of NADH, because NADH was a strong inhibitor of G3PDH in this microorganism.
A comparison of three methods for estimating dental plaque removal from individual teeth
Authors: Rubright W. C. , Johnson W. , Spivey J. D. , Jakobsen J.
Published: December 2007

The purpose of this study was to determine the efficiency of dental plaque removal, in vitro, by physical force. Of the 3 methods used, turbidity was the most sensitive for measuring microgram amounts of plaque. Air‐dried weight and dental plaque imprint assays (DP1A) complemented turbidity measurements by providing a weight standard and a new method for visualizing plaque bacterial structure before the stained imprint was transformed into numerical data. The amount of dental plaque removed from a tooth by physical force can be measured and described as a percentage of the total removable plaque on that tooth.
Associations between microbial species in dental root canal infections
Authors: Sundqvist G.
Published: December 2007

The existence of commensal or antagonistic relationships between microorganisms in the root canals of teeth with apical periodontitis was investigated. Samples were taken from 65 infected human root canals and were analysed according to species, frequency of occurrence and proportion of the total isolated flora. The most frequent species were Fusobacterium nucleatum. Prevotella intermedia, Peptostreptococcus micros, Peptostreptococcus anaerobius, Eubacterium alactolyticum, Eubacterium lentum and Wolinella recta. An odds ratio system was used to calculate positive or negative associations between the isolated bacteria. Strong positive associations were found between F. nucleatum and P. micros, Porphyromonas endodontalis, Selenomonas sputigena and W. recta. There was also a positive association between P. intermedia and P. micros, P. anaerobius and the eubacteria. In general, species of streptococci, Propionibacterium propionica, Capnocytophaga ochracea and Veillonella parvula showed no or negative associations with the other bacteria. The results are consistent with the concept of a special and selective environment occurring in the root canal that is due, in part, to the cooperative as well as antagonistic nature of the relationships between bacteria in the root canal.
Periodontal pathogens in the shallow pockets of immigrants from developing countries
Authors: McNabb H. , Mombelli A. , Gmür R. , Mathey‐Dinc S. , Lang N. P.
Published: December 2007

The aim of this study was to examine the distribution of typical periodontitis‐associated microorganisms in refugees arriving from non‐industrialized countries, and to relate the presence of these organisms to the periodontal condition of the subjects. Thirty males between 35‐44 years of age were surveyed. Dental plaque, calculus, gingivitis, loss of attachment, and probing depths were recorded for all surfaces. A total of 90 microbiological samples were taken with paper points from mesial sites of teeth 16, 36 and 41. Microbiological test sites were grouped by probing depths and loss of attachment. Only 16.8% of all surfaces had probing depths > 3 mm, although 90.7% of surfaces had loss of attachment > 1 mm. Twenty‐one sites with obvious periodontal destruction (PD > 3 mm, LA > 2 mm) showed the greatest recovery of Porphyromonas gingivalis (66.7%). However, 51 sites with minimal periodontal disease (PD > 3 mm, LA < 2 mm) and with no gingival recession also showed a relatively high detection frequency of P. gingivalis (34.1%). Twenty‐four of these samples came from 12 patients with no pockets > 5 mm and with less than 10% of all sites yielding pockets > 3 mm. The detection frequencies of Prevotella intermedia (91.6%), Bacteroides forsythus (25.0%), Wolinella spp. (33.3%) and Actinobacilluss actinomycetemcomitans (50.0%) were similar in these sites compared with periodontitis sites. Morphologically distinct isolates, from 19 individuals positive for A. actinomycetemcomitans, were serotyped by indirect immunofluorescence. Five isolates were identified as serotype a, 3 as serotype b and 9 as serotype c. Four isolates reacted only with monoclonal antibodies, specific for a common A. actinomycetemcomitans antigen. In the absence of oral hygiene, periodontal pathogens appear to be more widely distributed in shallow pockets. The results of this study suggest that differences in the microbiological composition of subgingival plaque may exist for this population group as compared with North American and European populations.
Demonstration of a bimodal coaggregation reaction between Porphyromonas gingivalis and Treponema denticola
Authors: Grenier D.
Published: December 2007

This study demonstrates a strong coaggregation reaction between 2 suspected periodontopathogens: Porphyromonas gingivalis and Treponema denticola. Other black‐pigmented oral bacterial species tested did not coaggregate with T. denticola. This specific interbacterial aggregation was bimodal, since heating of both cell types was required to completely eliminate the reaction. The coaggregation reaction occurred between pH 4 and 9. Under some conditions, arginine and D‐galactosamine were effective in preventing the coaggregation. The heat‐sensitive receptor on P. gingivalis was found to be loosely bound and could be released by a light ultrasonic treatment of the cells. It is suggested that the bacterial interaction described may participate in the establishment of a potentially pathogenic subgingival plaque.
The breakdown and utilization of peptides by strains of Fusobacterium nucleatum
Authors: Rogers A. H. , Gully N. J. , Pfennig A. L. , Zilm P. S.
Published: December 2007

It has been claimed that most strains of Fusobacterium nucleatum require peptides rather than free amino acids for growth. In contrast, we have shown that, under continuous culture conditions, all strains tested grow in a chemically defined medium (COM). The purposes of this study were to determine whether resting cells of F. nucleatum could attack unsubstituted peptides and whether growing cells could utilize a peptide fraction prepared from a commercial peptone. Resting cells cleaved all 19 peptides, containing 3‐6 residues, and the 4 key energy‐yielding amino acids ‐ Glu, His, Ser and Lys ‐ were rapidly taken up. A hydrophilic Casitone fraction, rich in Glu, promoted growth and peptides <1 kDa were rapidly utilized. The cleaved residues metabolized were those previously shown to limit growth in COM: Glu, Ser, His and Lys. The endopeptidase activities of Porphyromonas gingivalis would provide the necessary peptides for the growth of F. nucleatum, which may partly explain why these two organisms frequently coexist in periodontally diseased sites.
Comparison of the distribution of Actinomyces in dental plaque on inserted enamel and natural tooth surfaces in periodontal health and disease
Authors: Liljemark W. F. , Bloomquist C. G. , Bandt C. L. , Pihlstrom B. L. , Hinrichs J. E. , Wolff L. F.
Published: December 2007

The distribution of Actinomyces naeslundii, Actinomyces viscosus and Actinomyces odontolyticus in healthy and diseased adult populations was studied in 3 different ways. First, supragingival plaque formation at 2 through 72 h was examined in 12 periodontally healthy adults using a removable pre‐measured surface of enamel bonded to molars and premolars. Second, a cross‐sectional examination of the composition of both supragingival and subgingival plaque of unknown age was conducted in 205 adults exhibiting periodontal health to moderate disease. Third, the effects of oral hygiene instruction and root planing on the subgingival micro‐flora of a subset of 19 subjects with moderate periodontitis were examined. The evaluation of 12 adults revealed that the predominant species in early plaque formation (2, 4 and 8 h) was A. odontolyticus, A. viscosus and A. naeslundii were present in developing plaques in almost all subjects in 2‐h plaque, but absent in half the subjects when 4‐, 8‐ or 24‐h plaque was examined. These two species significantly increased in numbers per mm2 enamel surface area in 48‐ and 72‐h plaques. A. odontolyticus was not related to clinical signs of periodontal disease in 205 adults, and its subgingival proportions in plaque did not change following periodontal treatment of 19 individuals. A. naeslundii was found in significantly higher numbers in supragingival than subgingival plaques in the 205 adults examined. The mean proportion of A. naeslundii significantly decreased as the magnitude of probing depth and attachment loss increased. The proportions of A. naeslundii and A. viscosus were found to be significantly increased in subgingival plaques following periodontal treatment.
Dental plaque development on defined streptococcal surfaces
Authors: Skopek R. J. , Liljemark W. F. , Bloomquist C. G. , Rudney J. D.
Published: December 2007

Coaggregations between bacterial species have been widely studied in vitro but not in the mouth. A new in vivo assay was used to measure the rate and composition of indigenous plaque formation onto bovine enamel chips covered with a continuous layer of bacteria. Chips were covered with Streptococcus oralis ATCC 10557, which coaggregated with many oral species, or Streptococcus gordonii S7, which did not coaggregate with these oral species, and placed in the mouth for 4 and 24 h. There were no differences in the number of most indigenous bacterial species isolated from the two streptococcal surfaces. However, the number of Actinomyces viscosus as a proportion of total Actinomyces spp. was significantly different on the two surfaces at 24 h. With the exception of Actinomyces naeslundii and A. viscosus removed from the S7 surface, all indigenous species increased significantly in number from 4 to 24 h, irrespective of the streptococcal surface. This study demonstrated that interbacterial coaggregation had only a limited effect on in vivo plaque development. Thus suggesting that environmental factors, growth or other adherence phenomena are dominant in in vivo plaque formation.
Peptostreptococcus micros has a uniquely high capacity to form hydrogen sulfide from glutathione
Authors: Carlsson J. , Larsen J. T. , Edlund M.‐B.
Published: December 2007

There are high amounts of hydrogen sulfide in deep periodontal pockets. This volatile sulfur compound may be formed from L‐cysteine, but only low levels of this amino acid can be expected to be present in periodontal pockets. Glutathione, L‐γ‐glutamyl‐L‐cysteinylglycine, is in high concentration in most tissue cells, and this tripeptide may be more readily available as a source of hydrogen sulfide formation in the pockets. The ability of 37 different species of oral bacteria to utilize glutathione in hydrogen sulfide formation was studied. Of these species, only 2 species of Peptostreptococcus and 5 species of Fusobacterium formed high amounts of hydrogen sulfide from glutathione within 24 h. Since the initial rate of hydrogen sulfide formation was more than 5 times higher in Peptostreptococcus micros than in any of the other bacterial species, the kinetics of sulfide formation from glulathione by P. micros was further elucidated. The formation of sulfide followed quite closely hyperbolic Michaelis‐Menten kinetics. The maximal initial rate of sulfide formation (Vmax) was 163 ±2 nmol sulfide per minute per milligram of cellular protein. Half maximal initial rate (Km) was obtained at 7.4±0.8 μM glutathione. The initial rate of sulfide formation from L‐cysteine was much slower and was almost proportional to L‐cysteine concentration. This difference in kinetics of sulfide formation between glutathione and L‐cysteine strongly suggested that glutathione was actively transported into the cell, whereas the transport of L‐cysteine was more or less controlled by diffusion. The sulfide formation from the dipeptide L‐cysteinylglycine also followed quite closely hyperbolic Michaelis‐Menten kinetics. The maximal initial rate of sulfide formation (Kmax) from L‐cysteinylglycine was 75 ± 2 nmol sulfide per minute per milligram of cellular protein. Half maximal initial rate (Km) was obtained at 26 ± 4 μM L‐cysteinylglycine. Hydrogen sulfide may readily be formed from glutathione by P. micros in periodontal pockets. This is the first time that experimental data indicates active transport of di‐and tripeptides in anaerobic bacteria.
The effect of incubation temperature on the specificity of the BANA (N‐benzoyl‐DL‐arginine‐naphthylamide) test
Authors: Feitosa A. C. R. , Amalfitano J. , Loesche W. J.
Published: December 2007

The hydrolysis of BANA by subgingival plaque samples is associated with the presence of either Treponema denticola, Porphyromonas gingivalis, and/or Bacteroides farsythus. A protocol in which pure cultures were incubated for 15 min at 55°C detected about 5 × 105 CPU of P. gingivalis and 1 × 106 CPU of T. denticola. Clinical studies indicated that the BANA test in this configuration will detect about 104 organisms in vivo as compared with the 105 to 106 organisms found with in vitro grown cells. The BANA test can be made less sensitive by decreasing the time and/or temperature of incubation, which could improve the specificity of the test. In the present study we determined the incubation parameters that would give optimal specificity when the plaque samples were removed from sites of gingival health. Twenty‐six approximal plaque samples were taken from each of 90 clinically healthy subjects and incubated with the BANA substrate on PerioScan cards (Oral‐B Laboratories) for 5 and 15 min at 35°, 45°, and 55°C. Subjects were randomly assigned to the various temperatures. Wooden toothpicks were inserted interproximally in all sites anterior to distal of the first molars and then each side of the toothpick was wiped onto the PerioScan card. The specificity of the BANA test relative to clinical health was 96% when the cards were incubated for 5 min at 35°C, but decreased to 50–70% when the cards were incubated for 15 min at 35°C or for 5 and 15 min at 45°C and 55°C. These findings indicate that the specificity of the BANA test can be improved by shortening the incubation period to 5 min and by reducing the incubation temperature to 35°C.
Changes in the prevalence of subgingival enteric rods, staphylococci and yeasts after treatment with penicillin and erythromycin
Authors: Helovuo H. , Hakkarainen K. , Paunio K.
Published: December 2007

The changes in the balance of microbial flora in the periodontium after antibiotic treatment were investigated in a blind study. The prevalence of gram‐negative enteric rods, staphylococci and yeasts was followed before and during penicillin or erythromycin treatment of 72 periodontitis patients without periodontal cleaning. The prevalence of subgingival coagulase‐positive staphylococci increased significantly following systemic penicillin therapy. After systemic erythromycin therapy, the prevalence of subgingival gram‐negative enteric rods increased. Ten of 24 (42%) patients receiving systemic penicillin therapy developed clinical evidence of periodontal abscesses. In the absence of conventional mechanical cleaning, systemic administration of penicillin and erythromycin antibiotic to patients with preexisting periodontitis may lead to periodontal superinfection with opportunistic organisms.
A successful method for quantifying viable oral anaerobic spirochetes
Authors: Chan E. C. S. , Siboo R. , Touyz L. Z. G. , Qiu Y.‐S. , Klitorinos A.
Published: December 2007

Spirochetes are markedly prevalent in periodontal disease but are not included as predominant cultivable organisms because of the inability to quantify them by viable count. A successful method was developed for enumerating viable oral spirochetes as colony‐forming units (CPU) in an agarose‐based medium. Treponema denticola, Treponema vincentii and Treponema socranskii in log‐phase growth in new oral spirochete (NOS) broth were used for evaluation of the method. Critical components of the method include enzyme‐free low temperature‐gelling (37°C) agarose in NOS medium in small tissue‐culture flasks into which the spirochetes were seeded and diluted. The flasks were anaerobically incubated in a glove‐box. Reliable, consistent and reproducible viable counts of pure spirochete cultures were obtained. The injurious effects of spirochete temperature‐sensitivity were averted by using molten agarose at 37°C. Distinctive colony morphologies of spirochete species could be compared from pure cultures. Addition of rifampin into the medium showed no decrease in spirochete CFU count. The method as described allows for selection of mutants and detection of biochemical activity and is potentially useful for enumeration of spirochetes from periodontal pockets as members of the predominant cultivable flora.
Identification of Actinobacillus actinomycetemcomitans: polymerase chain reaction amplification of IktA–specific sequences
Authors: Goncharoff P. , Figurski D. H. , Stevens R. H. , Fine D. H.
Published: December 2007

Actinobacillus actinomycetemcomitans has been strongly implicated in the etiology of localized juvenile periodontitis. Techniques used in the identification of this periodontal pathogen include cultural, biochemical, immunological and DNA hybridization analysis. In this study, we report the use of polymerase chain reaction (PCR) to amplify unique sequences of A. actinomycetemcomitans. Specific oligo‐nucleotide primers LKT2 and LKT3 were designed to hybridize to the A. actinomycetemcomitans lktA gene, which encodes leukotoxin, a putative A. actinomycetemcomitans virulence factor. The LKT2 and LKT3 primers amplified lktA‐specific sequences from all 12 A. actinomycetemcomitans strains tested. In another set of experiments, 13 other bacterial species, most of which are normal residents of the oral cavity, were tested with these primers. These PCR amplifications also contained 2 additional primers, RRN4 and RRN5, which served as positive controls; RRN4 and RRN5 were designed to amplify specific sequences of eubac‐terial 16S ribosomal DNA (rDNA). PCR amplifications of all bacterial species tested, including A. actinomycetemcomitans, yielded 16S rDNA‐specific DNA fragments. Furthermore, each bacterial species tested, with the exception of A. actinomycetemcomitans, failed to amplify lktA sequences. The LKT and RRN primers were used in further PCR experiments to detect A. actinomycetemcomitans directly from gingival fluid samples. The results clearly demonstrate the simplicity, rapidity, specificity and accuracy of the LKT primers in the identification of A. actinomycetemcomitans.
Seroclassification of hitherto nontypeable Actinobacillus actinomycetemcomitans strains: evidence for a new serotype e
Authors: Gmür R. , McNabb H. , van Steenbergen T. J. M. , Baehni P. , Mombelli A. , van Winkelhoff A. J. , Guggenheim B.
Published: December 2007

Serotyping of 89 Actinobacillus actinomycetemcomitans isolates by indirect immunofluorescence with serotype‐specific monoclonal antibodies yielded 10 nontypeable strains. The aim of the present study was to re‐evaluate the seroclassification of these strains with a different assay. Electroblotted antigens of nontypeable isolates and selected reference strains were immunostained with 37 human sera containing high antibody titers to A. actinomycetemcomitans. Such immunoblots typically showed an immunodominant, serotype‐specific antigen smear. Twelve human sera were found to recognize specifically serotype a, 10 serotype b and 9 serotype c. Three sera contained antibodies to 2 or all 3 serotype antigens; 3 sera had no activity to any reference strain smear antigen. There was complete agreement between the seroclassification of the reference strains with the monoclonal and the polyclonal reagents. Seven of the 10 strains, nontypeable with monoclonal antibodies, could also not be typed by the human sera. Of the remaining 3 strains, one belonged to a previously unrecognized serovar of serotype a, and 2 isolates expressed a novel smear antigen detected by the 3 human sera containing no antibodies to the serotype a, b, or c antigens. We propose that these 2 strains be assigned to a new A. actinomycetemcomitans serotype, designated serotype e.
Microbial associations in periodontitis sites before and after treatment
Authors: Wikström M. , Renvert S. , Johnsson T. , Dahlén G.
Published: December 2007

Duplicate samples from 110 periodontal sites of 6 mm or more pocket depth in 16 patients were analyzed for the presence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Capnocytophaga spp., Campylobacter rectus, Eikenella corrodens and Fusobacterium nucleatum. The sites were sampled before and after nonsurgical periodontal treatment. No statistically significant associations were found before treatment between any of the analyzed species. After treatment, statistically significant associations were found between E. corrodens and all the other species, F. nucleatum and P. intermedia; Capnocytophaga spp. and C. rectus; P. intermedia vs Capnocytophaga spp. and P. gingivalis; and C. rectus vs Capnocytophaga spp. and A. actinomycetemcomitans. Some of these associations could be explained either by patient‐related factors or site‐related characteristics such as the pocket depth. The proportion of P. gingivalis seemed to be unrelated to the proportion of P. intermedia in the samples. If one of the analyzed microbes was found in one of the sampled pockets in a patient, the probability of finding that microbe in all the sampled sites in the same patient before treatment was more than 50%. This probability was reduced after treatment for many species, especially P. gingivalis, which showed a probability of zero. The probability of detecting a bacterial species on at least one additional site if it was present on one in the same individual was nearly 100%, both before and after treatment, for all species studied. This study has shown several potential microbial associations in the subgingival plaque flora of deep periodontal pockets. Local factors of the periodontal pocket and factors related to the individual may mask the biological significance of these microbial interactions.
Salivary collagenase, elastase‐and trypsin‐like proteases as biochemical markers of periodontal tissue destruction in adult and localized juvenile periodontitis
Authors: Ingman T. , Sorsa T. , Konttinen Y. T. , Liede K. , Saari H. , Lindy O. , Suomalainen K.
Published: December 2007

The profile of salivary proteases and their cellular origin, with special to polymorphonuclear leukocytes and bacteria, was studied in localized juvenile periodontitis and compared with adult periodontitis and healthy controls. General proteolytic activity in saliva as well as collagenase, elastase‐like and trypsin‐like activity was measured. In addition, the sensitivity of salivary collagenase of patients with localized juvenile periodontitis to doxycycline inhibition was studied. The saliva of localized juvenile periodontitis patients contained low amounts of collagenase compared with adult periodontitis saliva, and almost all salivary collagenase was found to exist in endogenously active form, as was found to be the case also in adult periodontitis patients and healthy controls. The salivary collagenase of localized juvenile periodontitis patients was relatively insensitive to 100 μmol/1 doxycycline but was completely inhibited by 600 μmol/1 doxycycline, reflecting rather matrix metalloproteinase‐1(fibroblast‐type) than matrix metalloproteinase‐8 (polymorphonuclear leukocyte) enzyme. The saliva of localized juvenile periodontitis patients also contained low amounts of elastase‐like activity compared with the saliva of untreated adult periodontitis patients. Scaling and root planing caused a significant decrease in elastase‐like activity in the saliva of adult periodontitis patients. General proteolylic and trypsin‐like activities were also low in the saliva of localized juvenile periodontitis patients. Furthermore, the reducing agent β‐mercaptoethanol did not activate or inhibit the salivary trypsin‐like activity of localized juvenile periodontitis or adult periodontitis patients, although the reduclant readily activated partially purified Porphyromonas gingivalis trypsin‐like protease in a characteristic manner. Our results show low levels of polymorphonuclear leukocytes and microbe‐derived proteases in the saliva of localized juvenile periodontitis patients compared with the saliva of adult periodontitis patients. It thus appears that tissue destruction localized to incisors and first molars, characteristic of localized juvenile periodontitis, is not clearly reflected in saliva. However, in particular, elastase‐like activity (SAAVNA assay) of saliva would seem to be a good and simple indicator of adult (but not localized juvenile) periodontitis. The present results reflect differences in tissue destruction mediators or mechanisms in localized juvenile periodontitis and adult periodontitis. In addition, care should be taken in interpreting the results of salivary or mouthrinse biochemical markers revealing tissue destruction events in different forms of periodontal disease.
Microbiology of the pericoronal pouch in mandibular third molar pericoronitis
Authors: Leung W. K. , Theilade E. , Comfort M. B. , Lim P. L.
Published: December 2007

The microorganisms associated with mandibular third molar pericoronitis were investigated using direct microscopy and anaerobic culture method. The pericoronal pouch was sampled with paper points in A) 8 patients without mandibular third molar pericoronitis and B) 6 patients with mandibular third molar pericoronilis. Under the microscope, the microflora was found to be a complex mixture comprising gram‐positive and gram‐negative cocci, rods and filaments (including fusiform and curved rods), motile rods and spirochetes. Significantly higher proportions of motile, gram‐negative rods were found in group B than in group A. The predominant cultivable microflora of 9 samples: A (4) and B (5) comprised several species of facultative and obligate anaerobic bacteria, namely Peptostreptococcus. Streptococcus, Actinomyces, Eubacterium, Propionibacterium, Veillonella, Porphyromonas, Prevotella, Bacteroides, Fusobacterium, Campylobacter, Staphylococcus, Stomatococcus, Lactobacillus, Neisseria, Capnocytophaga, Haemophilia, Selenomonas and Centipeda species. The microflora in pericoronitis appeared similar to that of diseased periodontal pockets.
Recent approaches to the chemotaxonomy of the Actinobacillus‐Haemophilus–Pasteurella group(family Paseurellaceae)
Authors: Olsen I.
Published: December 2007

Many members of the Actinnobacillus‐Haemophilus‐pasturella group (family Pasteurellaceae) have been misclassified. This article reviews the chemotaxonomic characters that recently have been provided to improve the taxonomy of Pasteurellaceae. These include fatty acids of whole cells, of lipopolysaceharides and of single colonies, together with sugar contents of whole cells, of whole defaatted cells, of lipopolysaccharides and of single colonies. This article also review taxonomy aided by distribution of proteins in whose cells and outer membranes, distribution of enzymes in outer membrane vesicles and in whole cells, bacteriolysis induced by ethylenediaminetetraacetic acid and hen eggwhite lysozyme and the distribution of respiratory quinines. Furthermore, an overview of characters obtained through studies on genetic transformation, restriction enzyme analysis, restriction fragment length polymorphism, DNA‐DNA hybridization, DNA‐rRNA hybridization, and 16S rRNA sequencing is given.
Actinobacillus actinomycetemcomitans recovery from extracrevicular locations of the mouth
Authors: Müller H.‐P. , Lange D. E. , Müller R. F.
Published: December 2007

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 extra‐crevicular 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 check mucosa appears to be a promising tool in the diagnosis of a periodontal infection with A. actinomycetemcomitans.
Electron microscopy of phages in serotypes of Actinobacillus actinomycetemcomitans
Authors: Olsen I. , Namork E. , Myhrvold V.
Published: December 2007

Actinobacillus actinomyc̀etemcomitans, Actinobacillus ureae, Haemophilus aphrophilus, Haemophilus paraphrophilus, Haemophilus influenzas, Haemophilus parainfluenzae, Pasteurella haemolytica and Pasteurella multocida strains were examined by transmission electron microscopy for the presence of bacteriophages. Phages were detected in serotype a (SUNY 75) and e (UOH 1705) and in the fresh clinical isolates UOH Q1243 and UOH Q1247 of A. actinomycetemcomitans. Phages were not found in serotype b, c and d strains of A. actinomycetemcomitans, in the fresh clinical isolate UOH Q1244 of this species or in old strains (including reference strains) of related species from the Actinobacillus‐Haemophilus‐Pasteurella group.